',n_n_n-_ 


I 


REESE   LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 


XT* 


J£» 


e 


..   \ 

•,.-... 


:"/ 


S3 


1 


A  TEXT-BOOK 


OF 


ORE  AND  STONE  MINING. 


Morfes 

FOE   THE   USE    OV 

MANAGERS  OF  MINES  &  COLLIERIES,  MINING  ENGINEERS, 
SURVEYORS,  AND  METALLURGISTS. 


PRACTICAL  GEOLOGY  (AIDS  IN).    By  G.  A.  J.  COLE,  F.G.S.,  Prof, 

of  Geology,  Royal   College  of  Science,  Dublin.     With  numerous  Illustrations.. 
SECOND  EDITION.    10s.  6d. 

COAL  MINING.  By  H.  W.  HUGHES,  F.G.S.,  Assoc.  R.S.M.  With  490 
Illustrations.  SECOND  EDITION.  18s. 

MINE  SURVEYING.  By  B.  H.  BROUGH,  F.G.S.,  formerly  Instructor  of 
Mine  Surveying,  Royal  School  of  Mines.  FOURTH  EDITION,  Illustrated,  7s.  6d. 

TRAVERSE  TABLES  ;  computed  to  Four  Places  Decimals  for  every 
Minute  of  Angle  up  to  100  of  Distance.  By  RICHARD  LLOYD  GUEDEN,  Author- 
ised Surveyor  for  the  Government  of  New  South  Wales  and  Victoria.  THIRD- 
EDITION.  21s. 

BLASTING  AND  THE  USE  OF  EXPLOSIVES.     By  0.  GUTTMANN, 

A.M.lnst.  C.E.    With  Folding  Plates  and  Illustrations.    10s.  6d. 

ASSAYING.  By  J.  J.  BERINGER,  F.C.S.,  F.I.C.,  and  C.  BERINGER,. 
F.C.S.  SECOND  EDITION.  10s.  6d. 

ELEMENTS  OF  METALLURGY ;  The  Art  of  Extracting  Metals  from 

their  Ores.     By  J.  ARTHUR  PHILLIPS,  C.E.,  F.C.S.,  F.G.S.,  and  H.  BAUEBMAN,. 
F.G.S.    With  numerous  illustrations.    THIRD  EDITION.    36s. 


NEW    METALLURGICAL    SERIES 

RDITED    BY 

W.  C.  ROBERTS-AUSTEN,  C.B.,  F.R.S., 

Chemist  and  Assay  er  of  the  Royal  Mint ;  Prof,  of Metallurgy ,  Royal  College  of  Science. 


1.  INTRODUCTION  TO  THE  STUDY  OF  METALLURGY.   By  the 

EDITOR.     THIRD  EDITION.    12s.  6d. 

2.  GOLD.     By  T.  K.  ROSE,  Assoc.  R.S.M.,  B.Sc.,  Assistant-Assayer  of 

the  Royal  Mint.     21s. 

3.  COPPER.     By  THOS.  GIBB,  Assoc.  R.S.M.,  F.I.C. 

4.  IRON  AND  STEEL.     By  THOS.  TURNER,  Assoc.  R.S.M.,  F.I.C. 

5.  METALLURGICAL  MACHINERY.   By  H.  JENKINS,  Wh.Sc.,  Assoc.. 

E.S.M.,  Assoc.M.lnst.C.E.,  of  the  Koyal  Mint. 

6.  ALLOYS.     By  the  EDITOR. 

\*  Other  Volumes  in  Preparation. 


LONDON  :  CHARLES  GRIFFIN  &  CO.,  LTD.,  EXETER  STREET,  STRAND.. 


€      OF  THE         *     >t 
CVERSITT) 


A    TEXT-BOOK 


OF 


OEE   AND    STONE 

MINING. 


BY 

C.  LE   NEVE   FOSTER,  B.A.,  D.Sc.,  F.B.S., 

/'  - 

ASSOCIATE   OF   THE   ROYAL   SCHOOL   OF    MINES,    ONE   OF    HER    MAJESTY'S    INSPECTORS 

OF    MINES,    AND    PROFESSOR   OF    MINING    AT     THE    ROYAL   COLLEGE   OF 

SCIENCE,    LONDON,    WITH   WHICH    IS    INCORPORATED 

THE   ROYAL   SCHOOL   OF    MINES. 


WITH    FRONTISPIECE   AND   716   ILLUSTRATIONS. 


A??\ 

OF  THE  '        \ 

UNIVERSITY)  - 

°f  •£?• 


LONDON: 

CHAELES   GRIFFIN  &  COMPANY,  LIMITED, 
EXETER    STREET,   STRAND. 

1894. 

\_All  rights  resewed.] 


wr    j nt  ~ 

tJNIVERsiTT 


PEEFACE. 


THE  object  of  my  text-book  is  to  assist  students  in  acquiring 
a  knowledge  of  the  art  of  mining.  Books  and  lectures  are 
not  intended  to  take  the  place  of  practical  teaching  at  mines  ; 
but  they  render  the  training  more  thorough  and  complete 
in  many  ways :  they  serve  to  explain  the  principles  of  the 
art,  to  solve  difficulties  which  ^perplex  the  beginner,  to 
suggest  matters  which  he  should  observe,  to  tell  him  of 
things  beyond  his  ken,  and  to  supply  him  with  a  system  for 
arranging  his  ideas  methodically. 

It  will  be  seen  by  my  numerous  references  that  I  have  not 
hesitated  to  avail  myself  of  very  varied  sources  of  informa- 
tion, and  that  I  have  taken  care  to  avoid  dwelling  too  much 
upon  English  examples. 

As  far  as  possible  I  have  set  my  face  against  the  indis- 
criminate use  of  the  local  slang  of  any  particular  district. 
Mining  is  quite  difficult  enough  without  introducing  unneces- 
sary technical  terms,  and  if  words  which  are  generally  under- 
stood by  English-speaking  nations  will  express  our  ideas 
clearly,  it  is  far  better  to  employ  them  than  to  fall  back  upon 
provincialisms  which  vary  from  one  district  to  another ;  on 
the  other  hand,  certain  expressions  may  sometimes  recommend 
themselves  by  reason  of  their  pithiness,  for  adoption  into  our 
tongue. 

Within  the  limits  of  this  preface  it  is  impossible  to  name 


vi  PREFACE. 

all  the  persons  to  whom  I  am  indebted  for  matter  contained 
in  this  volume.  Many  useful  facts  have  been  picked  up 
while  visiting  mines  at  home  and  abroad,  and  in  the  course 
of  conversation  with  my  colleagues.  I  therefore  gladly 
record  my  obligations  to  mining  men  generally,  whom  I 
have  invariably  found  ready  to  give  me  the  benefit  of  their 
experience. 

I  have  to  thank  the  Council  of  the  Institution  of  Civil 
Engineers,  the  Council  of  the  Institution  of  Mechanical 
Engineers,  the  Editors  of  Engineering  and  of  the  Engineering 
and  Mining  Journal,  M.  Paulin  Arrault,  Mr.  Augustus  Bowie, 
Mr.  William  Galloway,  Messrs.  Letcher  and  Michell,  and 
others,  for  permission  to  reproduce  some  of  their  figures.  A 
few  of  the  blocks  have  been  borrowed  from  Mr.  Hughes' 
"  Text-book  of  Coal  Mining." 

Mr.  J.  G.  Lawn  and  Mr.  L.  H.  Cooke  have  given  me 
valuable  assistance  in  correcting  proofs,  and  the  former  espe- 
cially has  saved  me  from  some  of  the  pitfalls  which  beset  the 
path  of  an  author  who  is  passing  a  book  through  the  press. 
The  very  full  index  prepared  for  me  by  Mr.  S.  W.  Price  will 
facilitate  reference  to  my  pages. 


LLANDUDNO,  NORTH  WALES, 
May,  1894. 


UNIVERSITT 


GENERAL    CONTENTS. 


INTRODUCTION. 


CHAPTER  I.  —  MODE  OF  OCCURRENCE  OF  MINERALS. 


Classification    . 

PAGE 

3 

Gold  ore    . 

PAGE 
41 

Tabular  Deposits 

5 

Graphite    . 

50 

i.  Beds 

5 

Gypsum 

5° 

2.  Veins  or  Lod 

es 

Ice     . 

51 

Masses  . 

18 

Iron  ore 

51 

Examples 

20 

Lead  ore    . 

55 

Alum  . 

20 

Manganese  ore 

57 

Amber 

21 

Mica  . 

58 

Antimony  . 

21 

Natural  Gas 

59 

Arsenic 

21 

Nitrate  of  Soda 

62 

Asbestos     . 

21 

Ozokerite  . 

63 

Asphalt      . 

22 

Petroleum  . 

65 

Barytes 

23 

Phosphate  of  Li 

me 

67 

Borax 

23 

Potassium  Salts 

69 

Boric  Acid 

25 

Quicksilver  ore 

7i 

Carbonic  Acid 

25 

Salt    . 

75 

Clay  . 

26 

Silver  ore 

77 

Cobalt  ore  . 

27 

Slate  . 

79 

Copper  ore 

28 

Sulphur 

81 

Diamonds  . 

37 

Tin  ore 

83 

Flint  . 

39 

Zinc  ore 

85 

Freestone  . 

41  j  Faults 

87 

CHAPTER  II. — PROSPECTING. 


Chance  Discoveries  .        .         -93 
Adventitious  Finds  .         .         -95 
Geology  as  a  Guide  to  Minerals    97 
Associated  Minerals  .        .         -97 
Surface  Indications  .         .         -97 
Form  of  the  ground      .         .     98 

Sheading 
Hushing 
Piercing 
Lode  Lights  . 
Altered  Vegetatior 
Old  Workings 
Names  of  Places 
Divining  Rod 
Dipping  Needle 

i 

Gozzan  .... 
Indicative  Plants  . 
Animals  as  Indicators  . 

.     99 
.   103 
.   105 

106 
107 
107 
108 
no 
III 
III 


Vlll 


CONTENTS. 


CHAPTER  III. — BORING. 


Uses  of  Bore-holes    . 
Methods  of  Boring  Holes 
I.  Boring  by  Rotation 

Auger     . 

Diamond  Drills 


II.  Boring     by 
with  Rods 


Percussion 


PAGE 

113 

"3 
"3 

"3 
118 

124 


Iron  Rods  . 
Wooden  Rods     . 
III.  Boring    by    Percussion 

with  Rope       . 
American  System 


PAGE 
I24 


Mather    and 

System 


Platt's 


137 
137 

142 


CHAPTER  IY. — BREAKING  GROUND. 


Hand  tools        .         .       %.         .151 

Shovel 151 

Crowbar        .         .         .         .151 

Pick 152 

Wedge  .         .  .         .154 

Saws 154 

Tools  for  Boring  and   Blast- 
ing      154 

Machinery  for  Breaking  Ground  162 
Transmission  of  Power     .         .163 

By  Air 164 

Water      .  .         -171 

Electricity        .         .         .172 

Excavating  Machinery      .         .173 

I.  Steam  Diggers       .         .   173 

II.  Dredges         .         .         .175 

III.  Rock  Drills    .         .         .177 

i.  Rotary  Drills          .  177 


2.  Percussive  Drills    .   180 
IV.  Machines    for    Cutting 

Grooves .         .         -199 
i.  Mechanical  Picks 


2. 


Rock 


199 


Travelling 
Drills  . 

3.  Circular  Saws 

4.  Endless        Chains 

with  Cutters 

5.  Wire  Saw 

6.  Revolving  Bar  with 

Cutters 

V.  Machines  for  tunnelling  206 
Modes     of    using    Holes    for 

Breaking  Ground  .  .  .  207 
Driving  and  Sinking  .  .221 
Fire-setting  ....  225 
Excavating  by  Water  .  .  226 


20 1 
202 

204 
204 

206 


CHAPTER  V. — SUPPORTING  EXCAVATIONS. 


Timbering  ....  227 
Kinds  of  Timber  used  .  .  227 
Preservation  of  Timber  .  229 

Levels 232 

Shafts 236 

Working-places  .  .  .  244 

Masonry  .....  249 

Levels 250 

Shafts  .....  252 
Working  Places  .  .  .  254 


Metallic  Supports     .         .         .  255 
Levels  .        .         .         .  -         255 

Shafts 263 

Working  Places     .         .         .  265 

Watertight  Linings  for  Shafts  266 

Special  Processes      .        .        .271 

Boring  Method      .         .         .271 

Compressed  Air  Method        .  277 

Freezing  Method  .         .         .279 

Haase  Process       .        .         .  283 


CHAPTER  VI. — EXPLOITATION. 


Open  Works  .  .  .  .285 
Hydraulic  Mining .  .  .  292 
Excavation  of  Minerals  under 

Water  ....  302 
Extraction  of  Minerals  by  Wells 

and  Bore-holes  .         .        .  304 


Underground  Workings    . 
Beds 

A.  Pillar  Workings 

B.  Longwall  Workings . 
Veins         .... 


308 
309 
309 

322 

325 

340 


CONTENTS. 


IX 


CHAPTER  VII. — HAULAGE  OR  TRANSPORT. 


PAGE 

Underground    .                 .         .  348 

PAGE 

Machinery.         .        .  363 

By  Shoots      .                  .         .  348 

a.  Locomotives 

363 

Pipes        .                          .  349 

&.  Stationary     En- 

Persons    .                 .         .  349 

gines 

364 

Sledges     .                 .        .  350 

Conveyance  by  Boats    . 

372 

Vehicles   .                 .    .    .  350 

Above  Ground  .... 

373 

Wheelbarrow         .        .  350 

Shoots  

373 

Carts  and  Waggons       .  350 

Pipes     

373 

Railways        .         .         .351 

Persons  ..... 

375 

Power  Used       .         .  361 

Sledges  

375 

Human  Labour  .         .361 

Vehicles         .... 

JJ  J 

375 

Animal  Labour  .         .361 

380 

Gravity      .         .         .  362 

Aerial  Ropeways    . 

O 

380 

CHAPTER  VIII.  —  HOISTING  OR  WINDING. 

Motors,     Drums      and     Pulley 

Keps 

419 

Frames       ....  387 

Signals  . 

420 

Ropes,    Chains,    and    Attach- 

Safety Appliances 

422 

ments         ....  398 

Overwinding. 

422 

Receptacles       ....  404 

Stopping  Gear 

424 

(a)  Buckets        .         .         .  404 

Safety  Catches 

426 

(b)  Guided  Buckets   .         .  408 
(c)  Cage     .         .         .         .417 

Springs  . 
Testing  Ropes 

427 
427 

Other  Appliances      .         .         .418     Pneumatic  Hoisting 

427 

CHAPTER  IX.  —  DRAINAGE. 

Surface  Water  ....  429 

Accessories 

457 

Dams         430 

Pumping  Engines  below  ground 

466 

Drainage  Tunnels      .         .         .  433 

Worked  by  Steam      . 

466 

Siphons    .                 .         .         .  437 

Water      . 

469 

Winding  Machinery.         .         .  437 

Compressed 

Pumping  Engines  above  ground  441 

Air 

470 

Motors        ....  442 

Electricity 

470 

Rods  .         .                  .         .445 

Co-operative  Pumping 

473 

Pumps        ....  447 

CHAPTER  X.  —  VENTILATION. 

Atmosphere  of  Mines        .        .  475 

Fire  Damp  .... 

498 

Causes  of  Pollution  of  Air  in 

Carbonic  Acid    . 

Mines          .        .         .         .480 

Oxygen       .... 

505 

Natural  Ventilation  .        .        .  482 

Measuring    the    Quantity  and 

Artificial  Ventilation        .         .  490 

Pressure  of  the  Air    . 

506 

I.  Furnace  Ventilation        .  490 

Anemometers 

507 

II.  Mechanical  Ventilation  .  491 

Water  Gauge  . 

508 

Water  Blast         .         .491 

Efficiency  of  Ventilating  Appli- 

Steam Jet   .        .         .  492 

ances  

509 

Air  Pumps  (Fans)         .  492 

Resistance  caused  by  Friction  . 

510 

Testing  the  Quality  of  Air        .  498 

CONTENTS. 


CHAPTER  XI. — LIGHTING. 


Keflected  Daylight 
Candles     . 
Torches     . 
Lamps 


513 
513 
515 
515 


Wells  Light 
Safety  Lamps 
Gas  . 
Electric  Light 


516 

518 
523 
523 


CHAPTER  XII. — DESCENT  AND  ASCENT. 


Steps  and  Slides 
Ladders    . 


.   526  I  Backets  and  Cages   . 
.   527  |  Man  Engine 


534 


CHAPTER  XIII. — DRESSING. 


I.  Mechanical  Processes        .  538 
Washing         .         .         .538 
Hand  Picking        .         .541 
Breaking  Up          .         -542 
Agglomeration  of   Con- 
solidation .         .         .   565 
Screening      .         .         .  566 
II.  Processes  depending  upon 

Physical  Properties    .   568 
Motion  in  Water  .         .  568 
Simple  Fall  in  Water  .  570 
Upward  Current  Sepa- 
rators     .        .         .  574 
Separation  by  Water 
Flowing  down 

Planes  .  .  .579 
Plane  Tables  .  579 
Percussion  Tables  584 
Travelling  Belts  .  585 


Buddies  .  .  587 
Motion  in  Air  .  .  589 
Desiccation  ....  592 
Liquefaction  and  Distillation  .  597 
Magnetic  Attraction  .  .  600 
III.  Processes  depending  upon 

Chemical  Properties  .  607 
Solution,     Evaporation, 

and  Crystallisation    .   607 
Atmospheric    Weather- 
ing     ....  610 
Calcination  or  Roasting  611 


Cementation . 
Amalgamation 
Application  of  Processes 
Loss  in  Dressing 
Sampling 

Hand  Sampling 
Machine  Sampling 


616 
616 
620 
630 
632 
632 
634 


CHAPTER  XIV. — PRINCIPLES  OF  EMPLOYMENT  OF  MINING 
LABOUR. 


Payment  by  Time     .         .         .  637 
Measure  or  Weight  638 


Payment  by  Combination  of  these  64 1 
Value  of  Product   .  641 


CHAPTER  XV. — LEGISLATION  AFFECTING  MINES  AND  QUARRIES. 


Ownership        ....  653 

Taxation 655 

Working  Regulations        .         .  655 
Metalliferous  Mines  Regula- 
tion Acts   ....  656 
Coal  Mines  Regulation  Act   .  662 
Other  Statutes  affecting  Mines  662 
Alkali  Acts    .        .         .        .665 
Boiler  Explosions  Acts  .         .  666 
Brine  Pumping  Act       .         .  666 


Elementary  Education  Acts  .  666 
Employers'  Liability  Act  .  666 
Explosives  Act  .  .  .666 
Factory  and  Workshop  Acts  667 
Quarry  Fencing  Act  .  .  667 
Rivers  Pollution  Prevention 

Act  .....  667 
Stannaries  Act  .  .  .  668 
Truck  Acts  .  .  .  .668 


CONTENTS. 


XI 


CHAPTER  XYI. — CONDITION  OF  THE  MINER. 


Clothing  . 

Hat 

Boots    . 

Jacket  . 
Housing    . 

Barracks 


PAGE 
669 
67I 
672 

673 
673 
674 


Cottages 
Education 
Sickness   . 
Thrift 
Recreation 


PAGE 

677 
682 
683 
690 
696 


CHAPTER  XVII. — ACCIDENTS. 


Death  Rate  of  Miners  from  Ac- 
cidents         ....  698 
Relative  Accident  Mortality  Un- 
derground and  Aboveground   699 
Classification  of  Accidents       .  702 
Underground        .         .         .   704 
Explosions  of  Fire  Damp 
or  Coal  Dust  .        .         .  704 


Falls  of  Ground  .  704 

Shaft  Accidents  .  705 

Miscellaneous    .  .  706 

On  the  Surface      .  .  711 

By  Machinery  .  711 

Boiler  Explosions  .  711 

Miscellaneous  .  711 

Ambulance  Training  .  712 


EEEATA  ET   CORRIGENDA. 

Page  36,  line  10  from  bottom,  for  "  Kearsage  "          read   "  Kearsarge." 

»    36,    „   18          „          „        "33,359,ooo"  „  "33,350,000." 

„  124,    „    17  ,,          „        "Healey"  „  "BeaL" 

„  182,     „  10  „          „        "Githen"  „  "Githens." 

„  209,    „    17  „          „         "Nobel"  „  "Noble." 

„  311,    „     4  from  top  "detachod"  „  "detached." 

,,607,    „    16  „         „         "Buttengenbach"   „  "  Biittgenbach.'' 

„    675,  owing  to  an  error  in  the  original,  the  scale  is  incorrect,  and  the 
readings  should  be  multiplied  by  i^. 


LIST  OF  ILLUSTRATIONS. 


Frontispiece :  Overhand  Stoping,  Carn  Brea  Tin  Mine,  Cornwall. 
OCCURRENCE. 

FIG.  PAGE 

1.  Stratified  deposits,  section  ........        5 

2.  Lead  lode  in  slate,  Wheal  Mary  Ann,  Menheniot,  Cornwall        .        6 

3.  Tin  lode  in  granite,  West  Wheal  Basset,  Cornwall       ...         7 

4.  Section  of  lode,  Canton  mine,  Otago,  New  Zealand     ...        8 

5.  Diagram  to  show  underlie    .         .         .         .         .         .         .         .10 

6.  Measurement  of  underlie     .         .        .         .         .        .        .         .10 

7.  General  section  of  a  lode 10 

8.  Longitudinal  section  of  a  lode  showing  ore-bodies       .         .        .11 

9.  Intersection  of  veins     .         .         . 12 

10.  Section  of  vein  with  feeders 12 

11.  Plan  showing  fahlbands,  Kongsberg  silver  mines,  Norway   .         .  12 

12.  Change  of  strike  affecting  richness  of  a  lode        .         .         .         -13 

13.  Richness  or  poverty  of  parallel  parts  of  lodes  :  "  Ore  against  ore  "  17 

14.  Haematite  deposit,  Ulverston        .......  19 

15.  Calamine  deposit,  Altenberg,  Moresnet 19 

16.  Stockwork,  Mulberry  mine,  near  Bodmin,  Cornwall     ...  19 

17.  Borax  Lake,  California,  plan 24 

1 8.  Cobalt  ore,  Skutterud,  Norway    .......  27 

19.  ,,        „      New  Caledonia 28 

20.  Section  across  Mansfeld  district .        .         .         .        .  .28 

21.  „      of  Eduard  II.  Shaft,  Mansfeld          .         .         .         .         .30 

22.  Geological  map  of  Rio  Tinto,  Huelva,  Spain         .        .        .        .31 
23 


3 

27) 
28} 
29. 
30. 
3i- 
32. 

33- 

-34 

Cross-sections  of  San  Dionisio  Lode,  Rio  Tinto   .        . 

Map  of  Lake  Superior  copper  district  .... 
De  Beers  mine,  Kimberley,  vertical  section 
Plan  of  diamond-bearing  deposits,  Kimberley 
Section  of  strata  at  the  flint  mines,  Brandon,  Suffolk 
„            „         Salisbury  mine,  Johannesburg 

•         •       33 

:  H 

-     38 
.     40 
.      42 

|: 

„          auriferous  alluvium,  Caratal  District,  Venezuela 
„          showing  auriferous  "  rainwash,"  Caratal 

Saddle-reefs,  Bendigo  ........ 

•       44 
.       45 

46,47 

xiv 


LIST  OF  ILLUSTRATIONS. 


39.  Mount  Morgan  mine,  Queensland,   section  to  illustrate  geyser 

theory          .... 

40.  „  „  „       view  of  deposit        ... 

41.  „  „         sections  based  on  late  developments  . 

42.  Gypsum  mine,  Nottinghamshire  ..... 

43.  Sections  of  ironstone  bed,  Cleveland    .... 

44.  Chapin  Iron  mine,  Lake  Superior,  section    ... 

45.  Lead-bearing  sandstone,  Mechernich,  general  section 

46.  Evening  Star  mine,  Leadville,  Colorado,  section  .         . 

47.  Manganese  ore  bed,  near  Barmouth,  North  Wales        . 

48.  Natural  gas  ;  section  through  Findlay,  Ohio        .         . 

49.  Nickel  deposit,  New  Caledonia    ..... 

°        „      bearing  veins,  New  Caledonia 


48 
49 
50 
51 
52 
54 
55 
56 
58 
60 
60 

61 


„      deposit,  Sudbury,  Canada          .....         61,62 

Nitrate  of  soda,  Chili  .....  .  .62 

Ozokerite  at  Boryslaw,  Galicia,  plan    .         .  .  -63 

„  ,,  ,,         section        .  .  .64 

„        filling  fissures,  Boryslaw      .  .  .64 

Baku  oil  region,  section        ....  .  -65 

Spouting  oil  well,  Baku         ....  .  .66 

Deposit  of  phosphate  of  lime,  Beauval,  France  .  .       68 

Bed  of  phosphatic  nodules,  South  Carolina.  .  .       68 

Potassium  salts  and  rock  salt,  Stassfurt       .  .  70 

Quicksilver-bearing  sandstone,  section,  Ekaterinoslav,  Southern 
Eussia      ...........       72 

Cross  section  of  quicksilver  deposit,  Great  Western  mine,  California    73 
Longitudinal  section  ,,  „  „  -74 

Cross  section  of  Eureka  mine,  Nevada          .....       77 

...   80 


slate  beds,  Festiniog,  N.  Wales 
„          „  the  Oakeley  Quarries,  Festiniog 

Sulphur  bank,  Iceland 

„        seam,  near  Caltagirone,  Sicily 

Cross  sections  of  tin  veins,  St.  Agnes,  Cornwall 


81 
82 
82 

84 


Map  of  part  of  Vegetable  Creek,  New  South  Wales      ...  85 

Cross  section  showing  "deep-leads"  of  tin  ore,  Vegetable  Creek  86 

Wash-out  fault     ........        .        .  87 

Ordinary  fault      ........  88 

Step  fault     ...........  88 

Fault  with  zone  of  broken  rock    .         ......  88 

Measurement  of  throw  of  a  fault          .         .....  89 

Section  of  fault  indicating  amount  of  throw        ....  89 


Variation  of  throw  along  the  strike  of  a  fault 
Reversed  fault  showing  bending  of  strata 


Plan  showing  heave  of  vein  sideways   ...... 

Illustration  of  heave  sideways  produced  by  a  sliding  along  dip  of 
fault          ........... 

Schmidt  and  Zirnmermann's  rule         .....         - 


90 
90 

90 
91 

91 
92 


Succession  of  faults,  Penhalls  mine     ......       92 


PROSPECTING. 

89.  Section  of  mineral  vein  showing  projecting  outcrop  of  a  hard 
vein 


98 


LIST  OF  ILLUSTRATIONS.  xv 

FIG.  PAGE 

90.  Cross-section  of  lode  with  gozzan         .....         .     101 

91.  Longitudinal  section  showing  relation  of  the  gozzan  to  natural 

drainage  level  .         .         .         .  .         .         .         .         .      101 

92.  Use  of  the  divining  rod         .         .         .         .         .         .         .  1  1  1 

93.  Dipping  needle  used  in  searching  for  iron  ore      .         .         .         .112 

BORING. 

94.  Earth  auger  or  gouge  .         .         .         .         .         .         .        .         .114 

95.  Derrick  for  lifting  rods         .         .         .         .        .  .         .114 

96.  ,,        &c.,  for  boring  by  rotation      ......     115 

97.  Screwed  coupling  for  hollow  boring  rods     .         .         .         .         .116 

98.  Rotating  and  guiding  arrangements  and  loose  connection   .         .     117 

99.  Boring  bit  with  two  sets  of  cutters       .         .         .         .         .         .     1  1  7 

100.  Cutting  out  a  core  with  diamond  drill          .  .         .         .118 

101.  Plan  of  large  crown  for  diamond  drill          .         .         .         .         .118 

102.  Arrangement  of  core  tube  and  sediment  tube      .         .         .         .119 

103.  Core-extractor      .         .         .         .         .         .         .         .         .         .119 

104.  Dauntless  diamond  drill       ........     120 

105.  Little  Champion  diamond  drill    .         .         .         .         .         .         .123 

106.  Small  diamond  drill  for  prospecting    ......     123 

107.  Chisel  bit     ...........     125 

108.  Screw-joint  for  boring-rods  .......     125 

109.  „  ,,  .     ,,  with  connecting  socket     .         .         .     125 
no.  Lifting  hook  or  dog     .  .         .         .         .         .        .         .     125 

in.  Retaining  key       ..........     125 

112.  Cap,  or  lifting  ring  and  socket     .         .         .         .         .         .         .125 

113.  Portable  plant  for  boring  with  rods      ......     126 

114.  Set  of  tools  for  use  with  above     .......     127 

115.  Shell-pump  or  sludger  .        .         .         .         .         .         .        .         .128 

11    I  Oeynhausen's  sliding  joint  ........     129 


Free-falling  tool  ..........     129 

1  20.  Arrault's  free-falling  tool  used  with  bumping  piece     .         .         .130 

121.  Enlarged  view  of  catch  for  free-falling  tool         .        .        .        .130 

122.  Kind's  free-falling  tool         .         .         .         .         .         .         .         .130 

123.  Crow's-foot  ...........     131 

124.  Bell-screw    ...........     131 

125.  Riveted  lining  tube  with  screwed  joints      .         .         .        .         -131 

126.  Lining  tube  with  flush  screwed  joint  .        .        .         .         -131 

12  A  I  Rotating  tool  for  cutting  out  a  core    .        .        .         .        .         .132 

129.  Core  extractor     ..........     132 

1  3°    j-  Compass-case  for  marking  core          ......     133 

131.  Wooden  boring  rod  used  in  Galicia      .         .         .        .        .  134 

132.  Rig  for  boring  by  the  Canadian  system        .         .         .         .  135 

133.  American  rig  for  boring  a  well     .......  138 

134.  Rope-socket         ..........  139 

135.  Sinker-bar    ...........  139 

136.  Jars  ...........  139 

137.  Auger-stem  ...........  139 


*       ...........  '39 

140.  Temper  screw       ...         .......  140 

141.  Sand-pump  ...........  140 

142.  Method  of  working  maul  for  drive-pipe         .....  140 


cr  THE 
XTNIVERSITY 


xvi  LIST  OF  ILLUSTKATIONS. 

FIG.  PAGE 

143.  Boring  plant,  Mather  and  Platt's  system 143 

144.  Enlarged  view  of  Mather  and  Platt's  cylinder  and  pulley  .  -144 

145.  Mather  and  Platt,  boring  head  and  turning  device      .  .  .146 

146.  Recording  phial  for  Macgeorge's  clinograph         .         .  .  .147 

g  L  Survey  of  bore-hole,  Scotchman's  United  mine,  Victoria  .  149 


BREAKING  GROUND. 

149.  Poll-pick 152 

150.  Double-pointed  pick .         -152 

151.  Pick  used  for  cutting  jad,  Bath  stone  quarries     .         .         .         -152 

152.  ,,     with  movable  blade,  Mansfeld     .         .         .         .         .         -152 

153.  Acme  pick   .        .         .        .        .         .        .         .         .         .  153 

154.  Universal  pick     ..........  153 

155.  Cornish  gad          ..........  154 

156.  Saw  for  cutting  freestone    .         .         .         .         .         .         .  154 

157.  Elliott  drill 155 

158.  Ratchet  drill 155 

1 59.  Jumper  used  at  Mechernich 156 

160.  „          „     in  Northamptonshire       .         .         .         .         .         .156 

161.  „          »      in  Festiniog  slate  mines 156 

162.  „         „      in  Cleveland  iron  mines  .         .....     156 

163.  Borer  or  drill 156 

Jg4 1  Cutting  edge  of  drill,  Minera,  North  Wales          .        .        .        .158 

1 66.  Bore-hole  with  triangular  section         .         .         .         .  .  159 

167.  Hammer  for  single-handed  boring,  Festiniog      .         .  .  159 

168.  Cornish  mallet,  or  double-handed  boring  hammer        .         .         .  160 

169.  Tamping  bar 160 

170.  Needle,  or  pricker        .        . 161 

171.  Charging  spoon  and  scraper         .......  161 

172.  Claying  bar 161 

1 73  JKnox  system  of  boring  rending  holes 162 

175.  Reamer,  or  broach  for  enlarging  holes  by  the  Knox  system          .     162 

176.  Hanarte  air- compressor        ........     165 

177.  Dubois  and  Frangois  air-compressor 166 

178.  Ingersoll- Sergeant  air-compressor        ......     167 

179.  Valve  of  Ingersoll-Sergeant  air-compressor          .         .'       .         .     168 

180.  Arrangement  of  steam  and  air  cylinders      .         .         ...     168 

181.  Underground  reservoir  for  compressed  air,  Mansfeld  .         .169 

182.  Joint  for  compressed  air  main,  Blanzy         .         .  .         .170 

1  3  I  Mode  of  fixing  air  main  in  shaft .     170 


184, 

185.  Eadie  and  Sons' joint  for  lap- welded  pipe   .        ...  .170 

1 86.  Dunbar  and  Ruston's  steam  navvy       .         .       ~.         .         .  .     174 

187.  Kincaid  and  McQueen's  bucket  dredge        .         ...  .     176 

1 88.  Priestman's  grab  dredger    .         .         .         .         .         .  177 

189.  Steavenson's  twist  drill  on  carriage,  worked  by  electric  motor  .     179 

190.  ,,  ,,  „  „  petroleum  engine  ib'o 
I9O 

J92L  Bits  used  with  machine  drills      .        .        .        y        .        .  .181 

194) 

195.  Shaped  bars  of  steel  for  cross-bits       .         .         .         .         ;  .182 

196.  Barrow  drill .  .     183 

197.  Drill  mounted  on  stretcher  bar 184 


LIST  OF  ILLUSTRATIONS.  xvii 

FIG.  PAGE 

198.  Climax  drill 185 

1 9" -Bosseyeuse,  or  boring  ram  of  Dabois  and  Francois       .         .         .  186 
201.  Ingersoll-Sergeant  Eclipse  drill    .        .        .        .         .         .        .188 

2°^  j  Socket  for  holding  the  tool 189 

204.  Franke  drill 190 

205.  Use  of  Franke  drill  and  undercutting  chisel,  Mansfeld  copper 

mines 191 

206.  Hirnant  drill 192 


207.  Sergeant  drill 

208.  „  turning  mechanism 

209.  Adelaide  drill 

210.  Darlington  drill,  longitudinal  section  . 

211.  „  „      side  elevation 

212.  „  ,,      mounted  on  stretcher-bar 

213.  Marvin  electric  drill,  working  parts     . 

214.  Franke's  mechanical  chisel  .... 

215.  Gillott  and  Copley's  undercutting  machine  . 

216.  Walker's  circular  saw  . 


193 
194 

'95 
196 
196 
197 
198 

200 
203 
204 


217-  Wire  saw      ...........  205 

218.  Stanley's  tunnelling  machine,  side  elevation        ....  207 

219.  Elliott  multiple  wedge,  longitudinal  and  cross  sections      .         .  208 

220^ 

221  , 

-Strength  of  explosives  as  shown  by  Trauzl's  lead  block  test        .  216 

224' 
225^ 

226.  Detonator,  Nobel's,  treble  strength 218 

227.  „  „         quintuple  strength 218 

228.  Firing  a  charged  hole 219 

229.  Kifting  hole  with  air-space  above  charge,  Knox  system      .         .219 

230.  Simultaneous  fuse  of  Bickford,  Smith  &  Co 219 

231.  Brain's  high-tension  electric  fuse 220 

232.  Nobel's    „        „  „  „ 221 

233.  „         low-tension     „  „ 221 

234.  Planning  holes  for  driving  a  level  by  hand  .....  222 

235.  Section  of  lode  with  youge  or  selvaye 222 

236.  Arrangement  of  holes  for  driving  a  level  with  a  machine  drill 

(elevation) 223 

237.  Arrangement  of  holes  for  driving  a  level  with  a  machine  drill 

(longitudinal  section)         ........  223 

238.  Halkyn  drainage  tunnel,  arrangement  of  holes  for  driving  .  223 

239.  Driving  level  with  Ferroux  drill  and  bosseyeuse,  Bex,  Switzerland  224 

240.  Arrangement  of  holes  for  sinking  a  shaft,  Foxdale,  plan    .         .  225 
241-           »                   „                 ,,               „           ,,        section        .  225 

SUPPORTING  EXCAVATIONS. 

242.  Level  with  cap  or  bar  supporting  roof 232 

243-       »        »       »    and  leg 232 

44  [  Joints  between  cap  and  leg 232 

246.  Timber  frame  and  lagging  for  level 232 

247.  Horned  set  for  level  in  loose  ground   ......  233 

248.  Timber  frame  and  lagging  for  heavy  ground,  Comstock  lode      .  233 

249.  Timbering  for  level,  Rio  Tinto  mines 233 

b 


xviii  LIST  OF  ILLUSTRATIONS. 

FIG.  PAGE 

250.  Pigsty  timbering  for  wide  level,  cross-section       ....  234 

251.  „  „              ,,            „       section  along  line  of  strike        .  235 

252.  Spilling  in  loose  ground,  longitudinal  section      ....  236 

253.  „  ,,         ,,        cross  section          .....  236 

254.  Plank  lining  for  shaft,  plan 237 

255.  Shaft  frame  or  set 237 

256.  „         ,,     enlarged  view  of  joint 237 

257.  Plan  of  timbering  for  shaft,  Comstock  lode         ....  238 

258.  Section  through  dividing  „            „            ....  238 

259.  End  view  of  timbering  for  shaft  ,,  ,,            ....  238 

260.  Plan  of  timbering  for  shaft,  Calumet  and  Hecla  mine          .         .  239 

261.  Shaft  timbering,  Clausthal,  plan 240 

262.  „            „                ,,            end  view 241 

263.  Timbering  chamber  for  water-wheel,  Clausthal   .         .         .         .241 

264.  Plan  of  shaft  frame  for  spilling 242 

265.  Sinking  shaft  by  spilling,  vertical  section    .....  243 

266.  Prop  supporting  roof  of  bed         .......  244 

267.  Chocks  supporting  roof 245 

268.  Large  chocks,  Wieliczka  salt  mines 245 

269.  Pigsty  timbering  in  stopes,  Day  Dawn  mine,  Queensland    .         .  245 

270.  Square  set,  Comstock  lode,  Nevada,  elevation     ....  246 

271.  „            „               „            „        plan 246 

272.  „  „              „            „    application  in  overhand  stopes  246 

273.  „         Kichmond  mine,  Nevada  ......  247 

274.  „        timbering   in  overhand  stopes,  Broken  Hill  mines, 

sectional  elevation 248 

275.  „        timbering  in  overhand  stopes,  Broken  Hill  mines, 

horizontal  section          .                           ...  248 


276.  Joint  for  square  set,  Broken  Hill  mines 

277.  Square  sets  supporting  hanging  wall    . 

278.  Strengthening  square  sets    . 

279.  Dry  walling  for  level,  Forest  of  Dean  . 

280.  Level  lined  with  masonry,  Clausthal     . 

281.  Level  with  arch  of  masonry 

282.  ,,        „        „     at  side 

283.  Lining  shaft  with  brickwork 

284.  Shaft  lined  with  concrete,  Foxdale  mine 

285.  Stone  pillar  supporting  roof 


249 
249 
249 
250 
250 
251 
25i 
252 

253 
254 


286.  Halkyn  drainage  tunnel,  section  showing  iron  supports      ".         .255 

287.  „            „              „        cast-iron  prop  and  chair        .         .         .  255 

288.  „            „              „         section  of  iron  rail  used        .         .         .  256 

289.  Section  of  steel  beam,  Nunnery  Colliery,  Sheffield      .        .        .  256 

290.  Steel  beam  on  timber  legs 257 

291.  Rolled  steel  caps  and  legs  forming  frame  for  level       .        .         .  258 

^  i  Section  and  plan  of  steel  plate  used .258 

294.  Level  lined  with  curved  iron  rails,  Hartz     .         .         .        *•  '     •  258 

295.  Bent  steel  bar  for  supporting  roof  of  level  .         .        .        .        .  259 

296.  Steel  frame  in  two  parts  for  lining  level,  Anzin  ....  259 

297.  Cross  section  showing  joint          .         .        .        .        .        .        .  260 

298.  Steel  frame  in  three  pieces,  Anzin       .         .        .        .        .        .  260 

299.  Circular  frame  for  level,  channel  steel 261 

300.  Section  through  joint  of  the  frame      .         .        .        .   •     .     •   .  261 

301.  Circular  frame  for  level,  bulb-tee  steel         .        .        ...        .  262 

302.  Section  through  joint  of  the  frame       .         .         .         .       «.  262 

303.  Iron  ring  in  two  parts  for  supporting  shaft  lining       .         .         .  263 

304.  Shaft  lining,  ozokerite  mines,  Boryslaw       .....  264 

305.  King  of  channel  iron  for  shaft .  264 

306.  Section  through  joint  of  ring 265 


LIST  OF  ILLUSTKATIONS.  xix 

FIG.  PAGE 

307.  Prop  of  I-steel,  and  plan  of  end 266 

308.  Solid  wooden  tubbing  for  shaft,  plan 266 

309.  Sections  of  cast-iron  wedging  cribs 267 

310.  Section  through  coffering     ........  268 

311.  Segment  of  cast-iron  tubbing 269 

312  1  Cast-iron  tubbing  resting  on  curb 270 

314.  Small  composite  borer  or  trepan,  Kind-Chaudron  system    .         .  272 

315.  Large  composite  borer                           „            ,,            ,,  273 

316.  Section  of  tubbing  with  moss-box       „            ,,            „  274 

317.  „                .,            ,,            „      compressed,  and  false  tubbing  274 

318.  Enlarged  section  of  the  three  wedging  curbs       ....  274 

319.  Section  of  tubbing  at  Lievin         .......  276 

320.  Sinking  by  freezing  process  in  watery  strata,  Siberia  .        .         .  279 

321.  „                „                „                „            „            „      .  280 

322.  Poetsch's  freezing  process,  section  of  freezing  tube    .         .         .  282 

323.  „            ,,            „          vertical  section  of  shaft    .        .         .  282 


EXPLOITATION. 

324.  Open  workings  for  iron  ore,  Northamptonshire   ....  287 

325.  „          „         plan  showing  arrangement  of  workings        .         .  288 

326.  Section  of  terraces,  Penrhyn  slate  quarry    .....  288 

327.  View  of  opencast,  Kio  Tinto  mines       ......  289 

328.  Section  of  Mulberry  mine  near  Bodmin,  Cornwall       .         .         .  289 

329.  Section  showing  effect  of  a  large  blast,  Messina          .         .         .  290 

33°  I  Details  of  the  tunnel  for  large  blast        ,,  .        .         .         .291 

332.  China  clay  workings,  Hensbarrow,  Cornwall        ....  292 

333.  End  view  of  flume  and  trestle      .......  294 

334.  View  of  flume  carried  across  a  valley  ......  294 

335.  „            ,,          „          by  iron  brackets  on  side  of  cafton     .         .  295 

336.  Kiveted  wrought-iron  water  pipe          .        .        .        .        .        .  295 

338  I  Pressure  box  or  "bulkhead" 296 

339J 

340.  Monitor        ......         .....  296 

341.  Hydraulic  mining,  attacking  the  gravel  bauk      .         .         .         .  297 
342) 

343  I  Sluice  box .298 

344J 

345 

34    I  Hydraulic  elevator 300 


w 
348J 


349.  .,  „        at  the  Blue  Spur,  Otago,  New  Zealand  . 

350.  Working  salt  by  bore-hole,  Middlesbrough .... 

351.  Plan  of  bore-holes,  Middlesbrough       ..... 

352.  Section  of  underground  gypsum  quarries,  Paris  . 

353.  Plan  „  „  „  „      . 

354.  Underground  workings  for  stone,  near  Bath,  plan 

355.  „  ,,  „  „  vertical  section 

356-  .1  »»  it  »»  Plan      • 

357.  Plan  showing  pillars,  Marston  Hall  salt  mine,  Northwich    . 

358.  Vertical  section  ,,  „          „  „ 

359.  Underground  workings  for  slate,  Festiniog,  plan 

^60.  cross- section  . 


301 

305 
306 
309 
309 
3io 
310 
310 
3ii 
3" 
313 
313 


361.      „        „      „    French  Ardennes,  cross-section  313 


xx  LIST  OF  ILLUSTRATIONS. 

FIG.  PAGE 

362.  Working  ironstone,  Cleveland,  plan     .         .         .         .         .         .316 

363.  Eestronguet  tin  stream  works,  plan      .         .         .         .         .         .317 

364.  „  „  „        section 317 

365.  Cross-section  of  the  Ked  Point  and  Darnrn  channels,  California  .  319 

366.  Plan  of  longwall  workings,  Mansfeld  copper  mine       .         .         .  324 

367.  Transverse  section  of  an  ore  mine,  lode  worked  by  vertical  shaft  326 

368.  Longitudinal    „           „          ,,                326 

39  I  Underhand  stoping,  original  method 327 

371.  „  „         on  sides  of  winze          .....     327 

372.  Longitudinal  section  of  Dolcoath  mine,  Cornwall        .         .         .     328 

373.  Transverse  section  „  ,,  „  ...     329 

374.  Overhand  stoping,  with  rubbish  stowed  on  stulls         .         .         .     329 

375.  „  „         cross-section 330 

376.  „  „         excavation  left  open       .  .         .         .     330 

377.  ,,  „          on  a  narrow  lode,  cross-section      .         .         .     330 

378.  Working  a  wide  lode  with  filling  up,  Van  mine    .         .         .         .331 

379.  Wide  lode  worked  by  cross-cutting,  transverse  section         .         .     334 

380.  „  „  „  plan  .  ^      .         .         .         -334 

381.  „        worked  in  slices,  parallel  to  the  dip    ....     335 

382.  „        worked  in  horizontal  slices,  with  filling  up,  Fox  dale 

Mine 336 

?8    I  Working  a  wide  lode  having  a  hard  and  a  soft  part    .        .        •     337 

385.  Bio  Tinto,  pillar  and  chamber  workings,  vertical  section    .         .     339 

386.  „  „  „  „  plan     of      preliminary 

drivages  .         .     339 

387.  „  „  „  „  plan      of     completed 

chambers         .         -339 

388.  Working  "  churns,"  Forest  of  Dean     ...  .         .     340 

389.  Plan  of  De  Beers  Mine,  new  system  of  working  . 


390.  „     of  drivages  and  chambers 

391.  Vertical  section  of  drivages  and  chambers  . 

392.  HEematite  deposit,  North  Lancashire,  cross-section 

393.  „  „       plan  of  main  levels  and  crosscuts 

394.  ,,  „        plan  of  workings    . 

395.  „  „        section  of  working 

396.  Working  zinc  ore,  Diepenlinchen  mine 


HAULAGE. 


342 
342 
342 
343 
344 
345 
346 


39 Sections  of  rails 351 

399.  Steel  sleeper,  Legrand's 352 

400.  „        ,,         Howard's         ........  352 

401.  „        „         made  from  bridge  rail    .        .        .        .         .         .  353 

401  a] 

402  I  Clip  used  with  above .  353 

4020] 

403.  Sleeper  made  of  channel-iron 353 

404.  „            ,,        flat  bar-iron 353 

405.  Cast-iron  turnplate       .........  354 

406.  Turnplate  with  iron  bar  guides    .......  354 

407.  Mine  waggon,  Van  mine      ........  355 

4°    L  Mine  waggon,  with  sheet-iron  body  and  bent  sides      .         .        .356 

410  j      „  „  ,,     oval     body     and      automatic     lubrication, 

411)         Saint-Etienne         .........  359 


LIST  OF  ILLUSTRATIONS.  xxi 

FIG.  PACK 

412  |  Steel  waggon,  Llanbradach  colliery      ......  359 

414.  Self  -oiling  pedestal      .........  361 

415.  Diagram,  main  and  tail  rope  system     .                  .         .                  .  366 

4       Rice's  ciutch         ..........  369 


418) 

419  /-Endless  rope  system,  plans  of  sidings  ......  370 

420] 

421.  „           „           „       double  track      .          .....  371 

422.  Drums  and  air-brake  of  self-acting  incline,  Bilbao       .         .         .  377 

423.  Aerial  ropeway,  Otto's  system,  view  of  tub  .....  382 
424  j.       ?j            5j            ?j            M       iron  standard     .         .        .        .  383 

426.  „  „  „  „       clip,  side  view    .         .        .        .384 

427.  ,,            „            „            „        cross-section  of  clip    .         .         .  384 

428.  „            „            „            ,,        plan  of  clip          ....  384 

429.  ,,  „  „  „        Sheba    Gold  Mining    Company, 

Barberton         .......  384 

430.  „            „       Gottessegen  Colliery,  Upper  Silesia    .        .        .  385 

HOISTING. 

431.  Turbine  and  connections  for  winding,  Great  West  Van  mine      .  390 
432  1  Compound  winding  engine,  Llanbradach  Colliery        .         .         .391 

434.  Drum  with  reserve  length  of  rope        ......  392 

435.  „            „                 „            „        section    .                          .         .  392 


436.  Keel  for  flat  rope,  elevation 

437-       >,        »          »      Plan 

438.  Wooden  pulley-frame,  side  elevation 


394 
394 
395 
395 


439.         .,  „  front 

440-         >»  »  Plan 395 

441.  Wrought-iron  head-gear,  "  Kock  Shaft,"  De  Beers  mine      .         .  396 

442.  „  „  "  Incline  Shaft "       ,,          ,,          .  397 

443.  Winding  pulley 398 

443a.  Wire  rope  with  hemp  core 399 

444 1  ordinary,  new  and  when  worn  .....  400 

4451 

446|      |f        n     Lang's  lay    „     „        „       „ 400 

448 1  Latch  and  Batchelor's  "  flattened  strand "       .         .  400 

449  J 

450.  „        „         „        „  ,,  outside  view       .        .         .  400 

451.  „        „      Elliot's  "  locked  coil " 401 

452.  Spring  hook  for  attaching  rope  to  bucket,  &c.      ....  402 

453.  Capping  wire  ropes,  eye  spliced  on      ......  402 

454.  „          „        „         eye  made  with  screwed  clamps    .         .        .  402 
455-         ,,          »        .,-           >.       »        »        »»                »     section        .  402 
456.        ,,          „        „        socket  riveted  on         .                 .        .        .  402 

457) 

458^        „          „        „        for  locked  coil  rope,  outside  view  and  sections  403 

459  J 

„         „         „        improved  form  of  clamped  capping    .         .  403 

462.  Wrought-iron  kibble          „  „  „  ,,  .  404 

463.  Aerial  incline,  <;  Blondin,"  used  at  granite  quarries,  near  Aber- 

deen    407 


€cr  THE         Y  ^S. 
IVERSITY) 
OP  / 


xxii  LIST  OF  ILLUSTRATIONS. 

FIG.  PAGE 

464.  Galloway's  improved  wire  rope  guides  for  bucket        .         .         .     408 

465.  „  walling  stage,  elevation      ......     409 

466.  „  „  ,.       plan  of  lower  floor       ....     409 

467.  Filling  skip  in  shaft     .........     4" 

468.  Self  -discharging  skip,  De  Beers  mine,  plan  .         .         .         .412 

469.  „  „  „  „          „      side  elevation  .         .         .412 

470.  Improved  shoot  with  double  doors,  De  Beers  mine      .         .         .     413 

471.  Automatic  dumping  arrangement  for  inclines,  side  elevation       .     413 

472.  „  „  „  „  plan     .         •         •     4T3 

473.  „  „  „  perpendicular    "Rock"  shaft, 

De  Beers  mine,  side  eleva- 
tion .....  414 

474-  »  »  ,»  »»  »  front  eleva- 

tion of  a  part  .  .  .  415 

475.  Ormerod's  detaching  link      ........     4l& 

476 


Self-discharging  skip,  Frongoch  mine 


47* 
479 
480 

481.  Cage,  Comstock  lode,  front  elevation  .         .        .         .        .         .418 

482.  „  „  „    side  elevation       ......     4l8 

483) 

484  \  Haniel  &  Lueg's  keps  for  cage      .......     42° 

485] 

Detaching  hooks,  King  &  Rumble's     ......     422 


„       Walker's 423 

490.  „  „  „          open 424 

DRAINAGE. 

491.  Wooden  dam  in  level,  plan  .         .        .        .                 •        .        .  430 
49^  I  Spherical  wooden  dam 431 


496.  Brick  dam  in  shaft,  vertical  section     ......     433 

497  I  Galloway's  pneumatic  water  tank,  vertical  section       .         .         .     438 

499.  „  automatic  water  tank,  side  view        ....    439 

500.  „  „  „  front  view      .        .        .    *    .     440 

5°*l  Bowden's  automatic  tanks  for  use  on  slopes        .        .         .        .441 

503.  „  „  „       dumping  at  head  of  slope  .         .441 

504.  Compound  double-acting  pumping  engine,  Mansfeld  .         .         .     444 

505.  Strapping-plates  for  wooden  pump  rod         .         .         .         .    '     .     445 

506.  V-bob,  side  elevation 446 

507.  „      plan '.  -     .         .446 

508.  Fend-off  bob,  side  elevation 446 

509.  Running  loop,  side  view       ........     447 

510.  „  „      front  view 447 

511.  West  &  Darlington's  hydraulic  plungers  for  working  inclined 

rods 447 

512.  Drawing  lift  in  shaft,  vertical  section  .         .         .         .         .         .     449 

5*3  j.  Pump  bucket  for  single  valve 449 


LIST  OF  ILLUSTRATIONS.  xxiii 

FIG.  PAGE 

515.  Half -moon 449 

516.  Form  for  two  valves  attached  at  circumference  ....  449 

517.  „              „         „                     in  the  middle         ....  449 

518.  Shape  of  leather  band  for  packing  pump  bucket          .         .         .  449 

519.  Lifting  pump  used  on  the  Comstock  lode.    .         .         .         .         .  451 

520 )  Bising  main,  joint  and  mode  of  supporting  column  in  shaft,  Com- 

521)"     stock  lode 451 

522.  Plunger  pump  in  shaft,  vertical  section       .         .         .         .         .451 

5^3 1  Hake's  mouth  valve     .        . 453 

5*| 1  Butterfly  valve 453 

5^7  jTrelease's  valve    . 453 

529) 

530  \-  Teague's  noiseless  valve,  vertical  section,  side  view  and  plan      .  454 

530 

532.  Double-beat  valve  fixed  in  place,  vertical  section        .        .        .  454 

533-         »        »        ,,      open 454 

534.  „        ,,        ,,      elevation  of  valve  and  lower  seat            .        .  454 

535.  Kittinger  pump,  elevation 456 

536.  ,,              „      vertical  section 456 

537.  Balance  bob 457 

538.  West  and  Darlington's  hydraulic  counterbalance        .         .         .  458 
539-         »                  v                   »                   ,1             for  inclined  rods  458 

540.  Bochkoltz  regenerator . 459 

541.  Eossigneux's  system  of  counterbalancing    .....  460 

542.  „  „  ,,  plan      .        .        .        .460 

543.  Catches 461 

544.  Pumping  engine,  Shakemantle  Mine,  side  view  ....  462 

545.  „  ,,  „  „        front  view          .         .         .463 

546.  Pumps  fixed  in  shaf t  ,,                  ,,        side  view  .         .        .        .  464 

547.  „  „  „  „         front  view          .         .         .464 

548.  Pumps  in  shaft,  bottom  lift,  Shakemantle  Mine,  side  view          .  465 

549.  Plan  of  shaft     '                               „                    „     ....  465 

550.  Pumps  in  shaft,  bottom  lift         „                    „     front  view        .  465 

551.  Underground  pumping  engine,  Mansfield 468 

552.  „                „            „                „        plan      .        .        . '    '  .  468 

553.  Pulsometer,  vertical  section .  409 

554.  Moore's  hydraulic  pump       .         .         .         .         .         .  470 

555.  Pohlepump -~  •.         .  471 

556.  Pump  worked  by  compressed  air,  Evans  and  Veitch   .         .         .  472 

557.  „           „                     ,,             „      cylinders  for  working  valves  .  472 


VENTILATION. 

558.  Natural  ventilation  by  two  shafts  joined  by  a  level      .        .         .     483 

559.  „  by  adit  and  shaft  ......     483 


560. 
56i. 
562. 
563. 
564- 
565. 
566. 
567. 


by  two  shafts  joined  by  an  incline        .         .  483 

of  end  of  level 485 

„  „     bad 485 

of  a  single  vertical  shaft       ....  486 

of  an  incline          ......  486 

of  a  rise 486 

of  end  of  level  by  an  air-sollar      .         .         .  487 
„              „                  „              longitudinal 


^^^  section        .     487 

568.         „  „  „  „  „  „  •     487 


xxiv  LIST  OF  ILLUSTRATIONS. 

FIG.  PAGE 

569.  Natural  ventilation  of  shaft  by  an  air  pipe           ....  488 

570.  Method  of  ventilating  a  rise         .                          ....  488 

571.  „                    „            lower  levels      .                  ....  489 

572.  „                    „            by  winzes          .                  ....  489 

573.  Ventilating  furnace,  vertical  section    .                  ....  491 

574.  „                „        plan     ...                  ....  491 

575.  ,,                „        front  elevation     .                  .  491 

576.  Williams'  water-jet  apparatus      .         .                  ....  492 

577.  Teague's  aspirator        ....                  ....  493 

578.  Hartz  blower,  elevation        ...                  .  494 

579.  „          „        section  ....                 ....  494 

580.  Roots'  blower,  cross  section         .                          ....  494 

581.  Capell  fan,  vertical  section           .                           ....  495 

582.  ,,       „       cross  section     ...                ~ .         .         .         .  495 

583.  Guibal  fan,  vertical  section         .                          ....  496 

584.  Schiele  fan        „            „                                         ....  497 

585.  Waddle  fan 497 

586.  Lunge's  apparatus  for  testing  the  air  of  mines    ....  504 

587.  „            „            valve-tube,  vertical  section     ....  504 

588.  Water-gauge,  model  to  illustrate  action  of           ....  508 

589.  Murgue's  graphic  representation  of  the  influence  of  the  sides 

of  airways  upon  the  amount  of  friction  .         .         .         .         .  5 1 1 


LIGHTING. 

590.  Candle  holder,  United  States 514 

591.  .     „           „      ("  Spider  "),  Au&tralia    .         .         .         .         .         .  5:5 

592.  Lamp  for  burning  oil,  Scotland   .         .         .         .         .         .         .516 

593.  Wells  light 517 

594.  Davy  lamp 519 

595.  Clannylamp 519 

596.  Mueseler  lamp 520 

597.  Marsaut  lamp       ..........  521 

598.  Ashworth's  Hepplewhite-Gray  lamp 522 

599.  Sussmann  electric  lamp       ........  523 


DESCENT  AND  ASCENT. 

600.  Iron  ladder 529 

601.  Section  showing  manner  of  joining  two  ladders  ....  529 

602.  Arrangement  of  ladders  in  shaft  ......  530 


-  Double-rod  man-engine         ........  534 

605.  Single-rod  man-engine          ........  534 

DRESSING. 

606.  Rotary  diamond  washing  machine 540 

607.  Revolving  drum  for  washing  smalls  before  picking    .        ,.         .  541 

608.  Scraper 542 

609.  Ragging 543 

610.  Spalling        .  544 

611.  Cobbing        ,         .         .    »•"" 544 

612.  Bucking 545 

613.  Thin  wedge  for  splitting  slate,  North  Wales        ....  545 

614.  Blake's  rock-breaker,  section       .......  547 


LIST  OF  ILLUSTRATIONS.  xxv 

FIG.  PAGE 

615.  Dodge  crusher      ..........  548 

616.  lo-stamp  battery  with  wooden  frame  ......  549 

617.  Single  discharge  mortar        ........  549 

618.  Tappet 549 

619.  Cam      ............  549 

620.  Stamp  head,  shoe,  and  die   ........  549 

621.  Steel  shoe  and  die  before  and  after  wear     .....  550 

622.  Ball's  steam-hammer  stamp          .         .         .         .         .         .         '552 

623.  Leavitt's  differential  steam-cylinder    ......  553 

624.  Cornish  crushing  rolls          .         .         .         .         .         .         .         '554 

625.  Kolls,  cross  section       .........  554 

626.  Krom's  roll,  section 555 

627.  Krom's  crushing  rolls,  side  elevation  ......  555 

628.  Edge-runner 557 

629.  Ball  pulveriser,  Krupp-Grusonwerk,  cross-section         .         .  558 

630.  „             ,,                „                ,,           longitudinal  section     .         .  558 

631.  Carr's  disintegrator,  section         .......  559 

632.  Gates  crusher       ..........  560 

633.  Huntington  mill,  plan 561 

634.  „              ,,     sectional  elevation    ......  562 

635.  Paxman's  improved  roller  and  yoke,  section        ....  562 

636.  „                 „            ,,              „         plan 562 

637.  „                „             „              „             „ 563 

638.  Sawing  machine  for  slate     ........  564 

639.  Greaves'  circular  slate-dressing  machine     .....  565 

640.  Perforated  sheet-metal,  with  round  holes,  imm.           .         .         .  567 

641.  „  „         „  „  „  2mm.  .         .         .567 

642.  „              „         „             „             „            5mm.           .         .         .567 
6420.  Trommel  for  making  four  classes       ......  567 

643.  Experiment  to  show  separation  of  minerals  by  free  fall  in  water  569 

64^  I  Tossing  and  packing  in  keeve 571 

646.  Experimental  jigging-sieve .  571 

647-             »              jigger 572 

648.  Two-compartment  jigger,  front  sectional  elevation     .         .         .  573 

649.  „             „                 ,,       cross-section 573 

650.  Experimental  jigger  with  fixed  sieve   ......  573 

651.  Jigger  with  piston  moving  horizontally,  Frongoch  mine,  cross- 

section      574 

652.  Jigger  with    piston    moving    horizontally,  longitudinal    cross- 

section 574 

653.  Pyramidal  separator,  Jacomety  and  Lenicque,  section          .         .  575 

654.  „  „  „  plan     .          .         .575 

655.  Upward  current  separator,  Frongoch  mine,  section    .        .         .  576 

656.  „          „  „  „  plan         .         .         -576 

657.  Osterspey's  siphon  separator,  vertical  section      ....  578 

658.  .,  „  „          longitudinal      section     of     front 

chamber 578 

659.  „                „              „          plan 578 

660.  Cornish  self-acting  double  frame,  plan 580 

fa1  r  »,  ,  sectional  elevation  .        .        .580 

663.  Linkenbach  table,  sectional  elevation 582 

664.  „              „       plan        .        .       r 582 

665.  Kevolving  round  table,  Jacomety  andJtenicque  ....  584 

666.  „  „          „  „  W,,     '    plan    .        .        .584 

667.  Rittinger's  side-blow  percussion  table,  plan         ....  585 

668.  Frue  vanner,  diagrammatic  longitudinal  section          .         .         .  585 

669.  Stein's  endless  belt,  side  elevation 587 


xxvi  LIST  OF  ILLUSTRATIONS. 

FIG. 

670.  Stein's  endless  belt,  plan     .......  587 

671.  ,,  ,,          „     end  elevation        ..... 

672.  Convex  round  buddle,  sectional  elevation    .... 


673.  „  „  „        plan 

674.  Experimental  pneumatic  jigger 

675.  Clarkson-Stanfield  concentrator 

676.  Tanks  and  drying  floors  for  china  clay,  plan  and  a  cross-section 

677.  Kiln  for  drying  fuller's  earth,  section  .... 

678.  Euelle's  revolving  drier,  longitudinal  section 

679.  Large  kiln,  Sicilian  sulphur  mines,  vertical  section     . 

680.  „  „  „  „       plan       .... 

68 1.  Chase  magnetic  separator,  longitudinal  section  (diagrammatic) 

682.  Conkling  magnetic  separator 

683.  Hoffmann  magnetic  separator 

684.  Kessler  magnetic  separator . 

685.  Lovett-Finney  magnetic  separator 

686.  Ball-Norton  magnetic  separator  . 

687.  Buchanan  magnetic  separator  «  .      „  . 

688.  Friederichssegen  magnetic  separator,  longitudinal  section  . 

689.  „  „  ,,  plan  .... 

690.  Wenstrom  magnetic  separator 

691.  Edison's  magnetic  separator         ...... 

692.  Brunton's  calciner,  sectional  elevation         .... 

693.  Hockin's  calciner,  longitudinal  section        .... 
694-  ft  »          plan 

695.  Sampling — quartering . 

696.  ,,  shovel        .         .         .         .         .         ... 

697.  Clarkson's  rapid  sampler 

698.  Bridgman's  ore-sampler,  first  apportioner 


587 
588 
588 
590 
591 
593 
595 
596 
599 
599 
60  1 
60  1 
602 
603 
603 
603 
604 
605 
605 
605 
606 
614 
615 


633 
635 
635 


699.     „       „      second   „ 635 


CONDITION  OF  WORKMEN. 

700.  Barracks  for  workmen,  Eisleben,  front  elevation          .         .         .  675 

701.  ,,                ,,                    ,,          ground  plan     ....  675 

702.  Cottage,  Bolsover  Collieries,  front  elevation        ....  678 

703-         ,,               „                >,          back        „ 678 

704.         „                „                „          first  floor  plan          .         .         .  "      .  678 

70S-         »                i.                »          ground  plan 678 

706.  Dry  or  changing  house,  Levant  Mine,  Cornwall,  side  elevation  .  680 

707-        »            »             „                   »                 „           plan         .        .  680 

708.  Shower-baths,  Anzin  Collieries,  France 68 1 


ACCIDENTS. 

709.  Lowmoor  jacket  and  Furley  pattern  stretcher     .         .  .  .712 

710.  Placing  stretcher  on  Ashford  litter      .         .         .         .  .  .713 

711.  Ashford  litter ;  .     713 


LIST    OF    ABBREVIATIONS. 


Ann.  Mines. — Annales  des  Mines. 

Ann.  Hep.  B.  Cornwall  Pol.  Soc. — Annual  Report  of  the  Royal  Cornwall 
Polytechnic  Society. 

B.  u.  h.  Z. — Berg-  und  hUttenmannische  Zeitung. 

Bull.  Hoc.  Lid.  Hin.— Bulletin  de  la  Societe  de  1' Industrie  Minerale. 

Coll.  Guard. — The  Colliery  Guardian. 

Comptes  Rendus  Mensuels,  Soc.  Ind.  Min. — Comptes  rendus  mensuels  de  la 
Societe  de  1'Industrie  Minerale. 

Eng.  Min.  Jour,  or  E.  M.  J. — The  New  York  Engineering  and  Mining 
Journal. 

Jahrb.  f.  d.  Berg- und  Hiittenwesen  im  K.  Sachsen. — Jahrbuch  fiir  das  Berg- 
und  Hiittenwesen  im  Konigreiche  Sachsen. 

Jahrb.  f.  Geol.  Min.  Palaont.—  Jahrbuch  fiir  Geologic,  Mineralogie  und 
Palaontologie. 

Jour.  Eoy.  Inst.  Cornwall. — Journal  of  the  Royal  Institution  of  Cornwall. 

Jour.  Soc.  Arts. — Journal  of  the  Society  of  Arts. 

Jour.  Soc.  Chem.  Ind. — Journal  of  the  Society  of  Chemical  Industry. 

Mem.  Geol.  Survey. — Memoirs  of  the  Geological  Survey  of  Great  Britain. 

Min.  Jour. — Mining  Journal. 

Min.  Stat. — Mineral  Statistics  of  the  United  Kingdom. 

Neues  Jahrb.  f.  Miner.  Geol.  u.  Palaontologie. — Neues  Jahrbuch  fiir 
Mineralogie,  Geologic  und  Palaontologie. 

Oest.  Zeitsckr.  f.  B.-u.  H.-  Wesen. — Oesterreichische  Zeitschrift  fur  Berg  - 
und  Hiittenwesen. 

Phil.  Trans. — Philosophical  Transactions. 

Proc.  Fed.  Inst.  M.  E. — Proceedings  of  the  Federated  Institute  of  Mining 
Engineers. 

Proc.  Inst.  Civil  Eng.  or  Proc.  Inst.  C.  E. — Proceedings  of  the  Institution 
of  Civil  Engineers. 

Proc.  Inst.  Mech.  Eng.  or  Proc.  Inst.  M.  ^.—Proceedings  of  the  Institution 
of  Mechanical  Engineers. 

Proc.  Min.  Inst.  Cornwall. — Proceedings  of  the  Mining  Institute  of  Corn- 
wall. 

Proc.  South  Wales  Inst.  Eng. — Proceedings  of  the  South  Wales  Institute  of 
Engineers. 

Quart.  Jour.  Geol.  Soc. — Quarterly  Journal  of  the  Geological  Society. 


xxviii  LIST  OF  ABBREVIATIONS. 

Rec.  GeoL  Survey,  India. — Eecords  of  the  Geological  Survey  of  India. 

Eep.  Miners'  Assoc.  Cornwall. — Eeport  of  the  Miners'  Association  of  Corn- 
wall and  Devon. 

Stat.  Min.  France. — Statistique  de  1' Industrie  minerale  en  France. 

Trans.   Amer.   List.   M.   E. — Transactions  of  the  American  Institute   of 
Mining  Engineers. 

Trans,  Inst.  Eng.  and  Shipbuilders  in  Scotland. — Transactions  of  the  Insti- 
tute of  Engineers  and  Shipbuilders  in  Scotland. 

Trans.  Inst.  Marine  Eny. — Transactions   of  the  Institute  of   Marine   En- 
gineers. 

Trans.    Mancli.   GeoL   Soc. — Transactions  of  the    Manchester  Geological 
Society. 

Trans.  Min.  Assoc.  and  Inst.  Cornwall. — Transactions  of  the  Miners'  Asso- 
ciation and  Institute  of  Cornwall. 

Trans.    Min.    Inst.    Scotland. — Transactions   of   the   Mining    Institute    of 

Scotland. 
Trans.  N.  of  Eny.  List.  Min.  Eny. — Transactions  of  the  North  of  England 

Institute  of  Mining  and  Mechanical  Engineers. 

Trans.    E.    GeoL   Soc.   Cornwall. — Transactions    of   the  Koyal  Geological 

Society  of  Cornwall. 
Trans.  Technical  Soc.  Pac.  Coast. — Transactions  of  the  Technical  Society  of 

the  Pacific  Coast. 
Zeitschr.    d.    d.    geol.    Gesellsch. — Zeitschrift   der  deutschen   geologischen 

Gesellschaft. 

Zeitschr.  f.  B.-H.-u.  S.-Wesen.—  Zeitschrift  fur   das  Berg-  Hiitten-    und 
Salinenwesen  im  preussischen  Staate. 


A   TEXT-BOOK 


OP 


ORE   AND   STONE-MINING. 


INTRODUCTION. 

THE  art  of  mining,  in  the  broadest  sense  of  the  word,  consists  of 
the  processes  by  which  the  useful  minerals  are  obtained  from 
the  earth's  crust.  This  definition  is  wide,  for  it  includes  under 
the  term  "  mine  "  both  open  and  underground  excavations ;  but 
it  excludes  subterranean  workings  which  are  simply  used  as 
passages,  such  as  railway  tunnels,  sewers,  and  galleries  for  military 
purposes. 

The  word  "  mine "  is  derived  from  a  low-Latin  verb  meaning 
to  lead,  and  equivalent  to  "  ducere  ; "  we  have  the  French  word 
"  mener,"  from  the  same  source.  No  doubt  originally  the  mineral 
deposit  itself  was  called  the  "mine"  or  "  lead,"  and  this  signifi- 
cation has  not  been  entirely  lost,  for  we  still  find  the  word  "  mine  " 
used  as  a  synonym  for  "  seam  "  in  the  case  of  coal  and  ironstone. 

I  must  remark  that  the  word  "  mine,"  or  its  equivalent  in 
other  languages,  varies  in  signification  in  different  countries  on 
account  of  legal  enactments  or  decisions  which  define  it.  In  the 
United  Kingdom  it  is  the  nature  of  the  excavation,  and  not  the 
nature  of  the  mineral,  which  decides  whether  the  workings  are  a 
mine  or  not.  For  legislative  purposes  the  term  "mine"  is  restricted 
to  workings  which  are  carried  on  below  ground  by  artificial  light ; 
but  in  common  parlance  this  rule  is  not  observed,  and  the  word 
used  depends  upon  the  mineral  itself.  Thus  the  underground 
workings  for  building  stone  near  Bath,  and  for  slate  at  Festiniog, 
are  usually  spoken  of  as  quarries,  but  are  treated  legally  as 
mines. 

In  Belgium,  France,  and  Italy,  on  the  other  hand,  the  work- 
ings for  mineral  are  classified  according  to  the  mineralogical 
nature  of  the  substance  wrought.  The  French  law  of  1810  makes 
three  classes  of  workings :  mines,  minieres,  and  carrieres.  Deposits 
of  gold,  silver,  lead,  copper,  sulphur,  coal,  and  beds  or  veins  of 
iron  ore  form  mines.  Under  the  head  of  minieres,  for  which  we 
have  no  equivalent  word  in  English,  are  included  bog  iron  ore, 
pyritous  earths  fit  for  working,  sulphate  of  iron,  aluminous  earths 
and  peat,  whilst  the  carrieres,  or  quarries,  comprise  workings  for 


2  ORE  AND  STONE-MINING. 

stone,  clay,  sand,  etc.,  whether  above  or  below  ground.  The 
statute  of  1866  has  assimilated  the  minieres  to  the  quarries,  and 
the  law  now  becomes  very  like  that  of  Italy  (1859),  which  distin- 
guishes simply  mines  (miniere)  and  quarries  (cave).  Deposits  con- 
taining metallic  ores  (excepting  metal-bearing  sand  or  earth), 
sulphur,  bitumen,  coal,  or  lignite  are  worked  as  "  mines,"  whilst  pits 
from  which  sand  and  gravel  are  obtained  become  legally  "quarries.'' 
The  consequence  is  that  what  is  merely  an  underground  stone 
quarry  in  France  would  be  a  mine  in  England ;  whilst  open 
workings  for  iron  ore,  such  as  those  of  Northamptonshire,  would 
be  true  mines  under  the  French  or  Italian  laws. 

In  a  general  text-book  upon  mining,  it  is  therefore  necessary  to 
go  beyond  the  British  definition  of  a  mine  and  to  include  the 
methods  of  working  minerals  in  excavations  open  to  the  daylight, 
as  well  as  in  those  which  are  purely  subterranean. 

The  mining  of  coal  is  a  subject  of  so  much  importance, 
especially  in  this  country,  that  it  requires  a  special  treatise ; 
this  has  been  prepared  by  my  friend,  Mr.  H.  W.  Hughes,*  and 
my  task  consists  in  describing  the  methods  of  winning  and  work- 
ing all  other  useful  minerals,  whether  solid,  liquid,  or  gaseous. 
Furthermore,  as  it  is  customary  for  the  miner  to  cleanse  or  pre- 
pare his  ore  or  stone  for  sale,  I  shall  explain  the  processes  which 
are  usually  carried  on  at  the  mine,  and  can  be  fairly  included 
under  the  convenient  term  "dressing."  Finally,  a  few  remarks 
will  be  made  concerning  legislation  affecting  mines  in  the  United 
Kingdom,  the  condition  of  workmen,  and  the  accidents  to  which 
they  are  exposed. 

The  subject  has  been  divided  into  the  following  chapters: — 

(i)  Occurrence,  or  manner  in  which  the  useful  minerals  are 
found  in  the  earth's  crust. 

Prospecting,  or  search  for  minerals. 
Boring. 

(4)  Excavation. 

(5)  Supporting  excavations. 

(6)  Exploitation,  or  working  away  of  minerals. 

(7)  Haulage,  or  transport  along  roads. 

(8)  Winding,  or  hoisting  in  shafts. 

(9)  Drainage,  or  removal  of  water. 
(10)  Ventilation. 

(n)  Lighting. 

(12)  Descent  and  ascent. 

(13)  Dressing. 

(14)  Principles  of  employment. 
Legislation. 


(16 
(17 


Condition  of  workmen. 
Accidents. 

*  A  Text-Book  of  Coal  Mining,  London,  1892. 


(     3     ) 


CHAPTER  I. 

MODE  OF   OCCURRENCE   OF   MINERALS. 

Classification  of  mineral  repositories. — Beds. — Veins. — Masses. — Causes 
affecting  the  productiveness  of  veins. — Theories  concerning  the 
formation  of  veins. — Examples  of  mineral  deposits  arranged  alpha- 
betically.— Faults  or  dislocations. 

CLASSIFICATION. — Various  conditions  may  be  taken  as 
the  bases  of  classification  of  the  rocks  which  form  the  crust  of  the 
earth.  One  striking  characteristic  is  the  presence  or  absence  of 
beds  or  layers.  A  rock  made  up  of  parallel  beds,  or  layers,  or  strata, 
is  said  to  be  stratified  ;  a  rock  in  which  no  such  structure  exists 
is  called  iw  stratified.  When  we  examine  the  stratified  rocks 
closely,  we  find  that,  as  a  rule,  they  have  been  formed  at  the 
bottom  of  seas,  lakes,  or  rivers  by  the  gradual  deposition  of 
sediment,  by  precipitation  from  solutions,  and  by  the  growth  or 
accumulation  of  animal  or  vegetable  organisms.  As  instances 
may  be  cited  beds  of  sandstone  or  clay,  formed  by  particles  of 
sand  or  mud  settling  down  in  water ;  beds  of  rock  salt,  resulting 
from  the  gradual  drying-up  of  inland  seas ;  beds  of  limestone, 
formed  out  of  old  coral  reefs ;  beds  of  coal,  due  sometimes  to  plants 
growing  upon  the  spot  and  sometimes  to  plants  washed  into 
lakes  or  estuaries. 

The  unstratified  rocks  are  frequently  crystalline.  In  the 
case  of  recent  volcanoes  we  see  molten  rocks  issuing  forth  from 
the  earth,  spreading  over  it,  and  consolidating  into  a  crystalline 
mass,  and  we  may  fairly  assume  that  many  of  the  crystalline 
rocks  now  met  with  at  the  surface  were  at  one  time  in  a  soft  fused 
condition.  Internal  evidence  leads  to  the  belief  that  the  process  of 
consolidation  often  took  place  at  a  very  great  depth,  and  on  this 
account  geologists  have  subdivided  the  crystalline  unstratified 
rocks  into  volcanic,  which  hardened  like  recent  lavas  near  the 
surface,  and^tfomc,  which  became  solid  under  the  heavy  pressure 
of  thick  masses  of  superincumbent  strata. 

One  class  of  crystalline  rocks  has  given  rise  to  much  contro- 
versy, viz.,  the  rocks  in  which  the  crystals  of  the  constituent 
minerals  are  arranged  in  roughly  parallel  layers.  The  rock  has  a 
flaky  structure,  and  is  known  as  a  crystalline  schist.  Some 
crystalline  schists  have  all  the  appearance  of  being  altered  sedi- 


4  ORE  AND  STONE-MINING. 

mentary  strata  ;  in  others  the  foliated  structure  is  considered  to 
be  the  result  of  pressure  upon  pre-existing  crystalline  rocks. 
We  therefore  may  classify  the  principal  rocks  as  follows  : 

(Sedimentary  origin. 
Chemical  origin. 
Organic  origin. 

TT          ,-r.    !       (    Volcanic. 
2.  Unstratified  . 


The  crystalline  schists  must  be  placed  in  one  or  other  of  these 
two  great  divisions,  according  as  they  are  looked  upon  as  an 
altered  form  of  stratified  or  of  unstratified  rocks. 

This  classification  is  not  entirely  satisfactory.  For  instance  it 
separates  two  of  the  products  of  a  volcano.  Volcanic  ash  falling 
into  the  sea  will  settle  down  and  form  a  stratified  rock,  whilst 
the  lava  issuing  from  the  same  vent  is  unstratified.  Again  it 
does  not  include  sea-  water,  an  important  source  of  salt.  How- 
ever, for  the  purpose  of  the  miner  a  simple  classification  is 
advisable,  and  it  will  be  found  sufficient  for  his  purpose  so  long 
as  it  is  recollected  that  occasional  anomalies  must  be  expected. 

Any  one  of  the  five  classes  of  rocks  just  mentioned  may  be 
extracted  from  the  crust  of  the  earth  for  commercial  purposes. 

Among  the  bedded  or  stratified  rocks  coal  is  the  most  im- 
portant, but  in  addition  we  have  beds  which  are  commercially 
valuable  on  account  of  the  metals  they  contain,  such  as  copper, 
gold,  iron,  lead,  manganese,  silver,  and  tin,  or  precious  stones  such 
as  diamonds,  garnets,  rubies  and  sapphires  ;  other  valuable  beds 
are  native  sulphur,  rock-salt,  and  innumerable  kinds  of  stone  for 
building,  decoration,  paving  and  road-making,  clays  for  making 
pottery  and  cement,  oil-shale  and  alum-shale. 

From  the  unstratified  rocks  we  obtain  supplies  of  stone  for  a 
great  variety  of  purposes. 

In  addition  to  mineral  deposits,  which  consist  mainly  of 
original  constituent  members  of  stratified  or  unstratified  rocks, 
we  have  a  third  important  class  in  which  the  repository  of  the 
valuable  mineral  has  come  into  existence  subsequently  to  the 
consolidation  of  the  rocks  which  surround  it.  If  the  repository 
is,  roughly  speaking,  tabular  or  sheet-like,  it  is  called  a  mineral 
vein  or  lode,  and  if  in  any  other  form  it  is  a  mass. 

Hence  the  series  of  mineral  repositories  might  be  classed 
according  to  their  origin  as  follows  : 


Primary  origin       .    |     T  , 

(  Unstratified. 


Secondary  origin 


MODE  OF  OCCURRENCE  OF  MINERALS.  5 

But  even  here  we  encounter  difficulties,  for  unstratified  rocks 
sometimes  cccur  in  the  form  of  veins  ;  besides  which  primary 
origin  is  not  a  term  which  is  strictly  applicable  to  beds  formed 
from  sediment  which  consists  of  fragments  of  other  rocks. 

It  is  not  unnatural,  therefore,  that  outward  form  should  have 
been  chosen  as  a  convenient  basis  of  classification,  and  accordingly 
mineral  repositories  have  been  separated  into  : 


Tabular  or  sheet-like   .        If 

(   2.  Veins. 

Non-  tabular         .         .       3.  Masses. 

TABULAR  DEPOSITS.  —  These  are  repositories  which  have 
a  more  or  less  flattened  or  sheet-like  form.  They  may  be  divided 
according  to  their  origin  into  (i)  beds  or  strata;  (2)  mineral 
veins. 

(1)  Beds.  —  The  characteristic  feature  of  a  bed  or  seam  is  that 
it  is  a  member  of  a  series  of  stratified  rocks  ;  the  layer  above  it  is 
called  the  roof,  the  one  below  it  is  the  floor.     Its  thickness  is  the 
distance  from  the  roof  to  the  floor  measured  at  right  angles  to 
the  planes  of  stratification  ;  its  dip  is  the  inclination  downward 
measured  from  the  horizontal;   its  strike  is  the  direction  of  a 
horizontal  line  drawn  in  the  plane  of  stratification. 

The  thickness  of  workable  beds  varies  within  very  wide 
limits.  The  productive  part  of  the  copper-shale  at  Mansfeld  is 
only  3  inches  to  7  inches  thick  ;  and  one  of  the  beds  of  gold- 
bearing  conglomerate  at  Johannesburg  is  only  6  inches  to  2  feet 
across  ;  we  find,  on  the  other  hand,  the  lead-bearing  sandstone  of 
Mechernich,  in  Rhenish  Prussia,  is  100  feet  (30  m.),  and  a  bed  of 
brown  coal  at  Briihl  in  the  same  neighbourhood  no  less  than  131 
feet  (40  m.)  thick.  The  principal  bed  of  slate  at  the  Oakeley 
Quarry,  Festiniog,  is  120  feet  thick  (36-5  m.). 

It  must  not  be  supposed  that  the  thickness  of  a  bed  necessarily 
remains  uniform.     Occasionally  this  is 
the  case  over  a  very  large  area;   but  FlG*  *• 

frequently  the  thickness  varies,  and 
the  bed  may  dwindle  away  gradually, 
or  increase  in  size,  or  become  divided 
into  two,  owing  to  the  intercalation  of 
a  parting  of  valueless  rock;  but,  in 
spite  of  such  variations,  a  bed  is  much 
more  uniform  in  thickness  and  com- 
position than  a  vein.  •  Fig.  i  shows 

beds  of  shale,  limestone,  iron  ore  and  sandstone,  any  one  of  which 
may  be  the  object  of  a  mining  undertaking. 

(2)  Veins  or  Lodes.  —  Veins  or  lodes  are  more  or  less  tabular 
or  sheet-like  mineral  deposits,  formed  more  or  less  entirely  since 
the  enclosing  rocks  (country],  and  either  occupy  ing  cavities  formed 


ORE  AND  STONE-MINING. 


FIG.  2. 


originally  by  fissures,  or  consisting  of  rock  altered  in  the  vicinity 
of  fissures.  A  simple  and  typical  example  of  a  vein  is  shown  in 
Fig.  2,  representing  a  lead  lode  in  slate  at  Wheal  Mary  Ann  in 
Cornwall.*  It  is  evident  that  a  fissure  in  the  slate  has  been 
filled  up  by  the  successive  deposition  of  bands  of  mineral  on  both 
sides.  The  unfilled  cavities  are  called  lochs  (Wales  and  Isle  of 

Man),  or  vugsft  (Cornwall).  The 
definition  given  above  differs  some- 
what from  that  of  some  standard 
authors,  whose  opinions  I  will  quote. 
Werner  says  :J  "Veins  are  special 
tabular  mineral  repositories  which 
nearly  always  cut  across  the  strati- 
fication of  rocks  and  so  far  have  a 
different  lie  to  them,  and  are  filled 
with  a  mineral  mass  differing  more 
or  less  from  the  surrounding  rocks ; " 
and  further,§  "  Mineral  veins  may 

be  more  exactly  defined  by  saying  that  they  are  fissures  in  the 
rocks  which  have  been  subsequently  filled  up  with  various 
minerals  differing  more  or  less  from  the  surrounding  rock." 
Carne's  definition  is  this :  ||  "By  a  true  vein,  I  understand 
the  mineral  contents  of  a  vertical  or  inclined  fissure,  nearly 
straight,  and  of  indefinite  length  and  depth."  Von--£!otta!s~-is 
shorter  :^[  "  Mineral  veins  are  the  contents  of  fissures,"  whilst 
Grimm  says  :**  "  Veins  are  fissures  in  rocks  which  have  been 
wholly  or  partly  filled  with  minerals."  Von  Groddeck's  explana- 
tion runs  thus  :tt  "  Veins  are  fissures  which  have  been  filled  up." 
In  Geikie's  text-book  we  find  :%%  "A  mineral  vein  consists  of  one 
or  more  minerals  deposited  within  a  fissure  of  the  earth's  crust." 
Professor  von  Sandberger's  idea  of  a  vein  is  the  same  :§§  "True 
veins,  that  is  to  say,  fissures  filled  with  ores."  In  France  ||||  and 
similar  definitions  prevail. 


*  C.  Le  Neve  Foster,  "  Kemarks  on  the  Lode  at  Wheal  Mary  Ann,  Men- 
heniot,"  Trans.  R.  Geol.  Soc.  Cornwall,  vol.  ix.  p.  153. 

t  Probably  taken  from  the  Cornish  word  "  fogou/  a  cave. 

J  A.  G.  Werner,  Neue  Theorie  von  der  Entstehung  der  Gdnae.    Freiberg, 

I79i,  P-  3- 

§  Ibid. 

||  J.  Carne,  "On  the  Kelative  Age  of  the  Veins  of  Cornwall,"  Trans.  It. 
Geol.  Koc.  Cornwall.     Penzance,  1822,  vol.  ii.  p.  51. 

T  Die  Lehre  von  den  Erzlagerstdtten.     Freiberg.  1859,  p.  102. 

**  Die  Lagerstatten  der  nutzbaren  Miner  alien.     Prague,  1869,  p.  97. 

ft  Die  Lehre  von  den  Lagerstatten  der  Erze.     Leipsic,  1879,  p.  31. 

+J  Text  Booh  of  Geology .     London,  1882,  p.  591. 

§§  Vatersuchangen  iiber  Erzgdnge.     Wiesbaden,  1882,  p.  4. 

I!  ||  Haton  de  la  Goupilliere,  Cours  d1  Exploit  at  ion  des  Mines.     Paris,  1883, 

P-  33- 

HIT  V.  Zoppetti,  Arte  Mineraria.     Milan,  1882,  p.  16. 


MODE  OF  OCCURRENCE  OF  MINERALS.  7 

As  long  ago  as  the  year  1 864,*  Mr.  Richard  Pearce  brought 
forward  the  theory  that  many  of  the  tin  lodes  of  Cornwall  have 
been  formed  by  the  alteration  of  granite,  and  my  own  f  investi- 
gations have  convinced  me  that  he  is  right.  The  lodes  appear 
to  be  bands  of  stanniferous  rock  formed  by  the  alteration  of 
granite  in  the  vicinity  of  fissures.  The  tabular  mass  of  tin-bearing 
rock  10  or  15  feet  thick,  called  the  lode,  is  traversed  by  sundry 
fissures  and  passes  without  any  distinct  walls  or  boundaries  into 
non-stanniferous  granite;  sometimes  the  main  fissure  is  a  few 
inches  wide  filled  with  crystallised  quartz  and  other  minerals. 
This  filled-up  crack  answers  to  the  common  definition  of  a  vein, 
but  the  rest  of  the  stanniferous  mass  does  not.  It  has  no  definite 
bounding  planes,  it  contains  no 
fragments  of  the  surrounding 
rocks,  and  presents  no  appear- 
ance of  having  been  formed 
by  the  deposition  of  minerals 
upon  the  sides  of  an  open  rent 
(Fig.  3).  As  much  of  the  stan- 
niferous rock  as  will  pay  for 

working  is  known  as  the  lode.  i  f  3   | 

I  think  the  geologist  must  give 
way  and  suit  his  definition  to 

the  wants  of  the  miner.  It  is  too  much  to  expect  the  miner  to 
give  up  a  term  consecrated  by  universal  usage,  simply  because 
geologists  have  made  the  mistake  of  supposing  that  all  lodes  have 
been  formed  on  the  same  plan. 

If  Cornwall  furnished  the  only  exceptions  to  the  time-honoured 
definition  of  a  mineral  vein,  one  would  perhaps  hesitate  in  pro- 
posing any  alteration ;  but  when  similar  or  somewhat  similar 
cases  are  met  with  in  other  parts  of  the  globe,  the  necessity  for 
some  change  becomes  apparent. 

Mr.  Kendall  1  says  that  the  haematite  veins  of  the  Lake  District 
(England)  are  not  filled  fissures,  but  are  substitutioiial  deposits, 
the  result  of  a  gradual  replacement  of  the  original  rock  by  other 
minerals. 

Mr.  S.  F.  Emmons  §  takes  a  similar  view :  "I  consider  it 
reasonably  certain  that  a  very  large  proportion  of  the  so-called 
fissure-veins  in  the  Rocky  Mountain  region,  notably  those  in 

*  R.  Pearce,  "  The  Influence  of  Lodes  on  Rocks,"  Rep.  Miners"  Assoc. 
Cornwall.  Truro,  1864,  p.  18. 

t  C.  Le  Neve  Foster,  "  On  the  Great  Flat  Lode  South  of  Redruth  and 
Camborne  and  on  some  other  Tin-deposits  formed  by  the  alteration  of 
Granite,"  Quart.  Jour.  Geol.  8oc.,  London,  1878,  vol.  xxxiv.  pp.  640-653. 

£  J.  D.  Kendall,  "On  the  Mineral  Veins  of  the  Lake  District,"  Trans. 
Manch.  Geol.  Soc.  Manchester,  1884,  vol.  xviii.  p.  292. 

§  R.  C.  Hills,  "  Ore  Deposits  of  Summit  District,  Rio  Grande  County, 
Colorado."  Condensed  for  the  Engineering  and  Mining  Journal,  by  S.  F. 
Emmons.  Eng.  Mln.  Jour.  1883,  vol.  xxxv.  p.  334. 


s 


ORE  AND  STONE-MINING. 


Colorado  and  Montana,  are  simply  the  alteration,  silicification, 
and  mineralisation  of  the  country  rock  along  certain  planes  which 
for  some  reason  or  other  offered  exceptionally  easy  access  to  per- 
colating mineral  solutions,  and  are  not  the  filling  up  of  pre- 
existing cavities  in  the  rock,  as  is  generally  supposed  to  be  the 
characteristic  of  a  true  fissure-vein." 

Some  of  the  lodes  of  Otago,  New  Zealand,*  may  be  described  as 

belts  or  zones  of  auri- 

Fic.  4.  ferous  mica-schist  with- 

out any  definite  bound- 
aries ;  Fig.  4  shows  one 
of  them,  which  is  worked 
at  Canton  mine.  AA  is 
A  a  vein  of  quartz,  BB  a 
channel  or  zone  of  dis- 
turbed and  distorted 
schist,  CC  a  false  wall 
or  plane,  along  which 
there  has  been  a  shift- 
ing of  the  strata.  The 
vein  AA,  which  has 
been  formed  along  one 
of  the  lines  of  fracture 
and  dislocation,  is  called 
the  "  indicator,"  as  it 
acts  the  part  of  a  guide 
to  the  miner  in  his  en- 
deavours to  follow  the 
auriferous  channel ;  but 
the  precious  metal  is  not 
confined  to  the  space 
between  A  and  C. 

The  question  as  to 
what  constitutes  a  vein 
or  lode  has  been  more 
thoroughly  threshed  out 
in  the  United  States 
than  elsewhere,  because 
in  some  parts  of  that 
country  the  miner's 

title  .to  his  property  depends  upon  the  definition  of  the  word. 
The  consequence  is  that  the  term  "lode"  has  been  defined  by 
judicial  decisions. 

In  the  year  1877,  Mr.  Justice  Field,  in  the  celebrated  Richmond 
v.  Eureka  case,  ga,ve  the  following  interpretation :  f  "  We  are  of 

*  Rickard,   "The  Gold-fields   of    Otago,"    Trans.    Amcr.    List.    M.   E. 
Meeting  of  June  1892. 
t  Transcript  of  Record.    Supreme  Court  of  the  United  States,  Nos.  1038 


CANTON  MINE 


MODE  OF  OCCURRENCE  OF  MINERALS.     9 

opinion,  therefore,  that  the  term  lode,  as  used  in  the  Acts  of 
Congress,  is  applicable  to  any  zone  or  belt  of  mineralized  rock 
lying  within  boundaries  clearly  separating  it  from  the  neighbour- 
ing rock." 

This  definition,  which  has  been  framed  for  the  practical  work- 
ing of  an  Act  of  Congress,  is  not  a  satisfactory  one  for  the 
scientific  miner,  because  it  would  include  a  bed  or  seam,  whilst  it 
would  exclude  some  of  the  Cornish  tin  lodes  which  have  no  distinct 
boundaries. 

Some  subsequent  decisions  cover  more  ground,  for  they  ignore 
the  question  of  shape.  Judge  Hallett  *  gave  the  following  charge 
in  the  case  of  Hymanv.  The  Aspen  Mining  and  Smelting  Company  : 
"  It  may  be  said  that  with  ore  in  mass  and  in  position  in  the 
body  of  a  mountain,  no  other  fact  is  required  to  prove  the 
existence  of  a  lode  of  the  dimensions  of  the  ore.  As  far  as  it 
prevails,  the  ore  is  a  lode  whatever  its  form  or  structure  may  be, 
and  it  is  not  at  all  necessary  to  decide  any  question  of  fissures, 
contacts,  selvage,  slickensides,  or  other  marks  of  distinction,  in 
order  to  establish  its  character.  As  was  said  in  another  case  f  in 
this  court :  '  A  body  of  mineral  or  mineral-bearing  rock  in  the 
general  mass  of  the  mountain,  so  far  as  it  may  continue  unbroken 
and  without  interruption,  may  be  regarded  as  a  lode,  whatever 
the  boundaries  may  be.  In  the  existence  of  such  body,  and  to  the 
extent  of  it,  boundaries  are  implied.' " 

While  quoting  these  decisions  on  account  of  their  importance 
to  prospectors  and  to  holders  of  mining  property  in  the  United 
States,  I  think  it  wise  to  adhere,  for  the  purposes  of  the  student, 
to  the  definition  I  have  proposed,  and  to  consider  tabular  shape 
and  origin  subsequent  to  that  of  the  enclosing  rocks  as  the  chief 
characteristics  of  mineral  veins  or  lodes.  No  doubt  a  very  large 
number  of  mineral  veins  are  simply  the  contents  of  fissures ; 
others  are  bands  of  rock  impregnated  with  ore  adjacent  to  fissures  ; 
others,  again,  have  been  formed  by  the  more  or  less  complete 
replacement  of  the  constituents  of  the  original  rock  by  new 
minerals. 

Veins  may  occur  in  stratified  or  unstratified  rocks,  and  in  the 
former  they  usually  cut  across  the  planes  of  bedding. 

Like  a  bed,  a  vein  has  its  dip  and  strike ;  but  as  the  dip  of 
veins  is  generally  great,  it  is  often  measured  from  the  vertical, 
and  is  then  spoken  of  as  the  underlie,  underlay,  or  hade.  Instead 
of  being  expressed  in  degrees,  the  underlie  is  sometimes  measured 
by  the  amount  a  lode  plunges  under  cover,  or  away  from  the  vertical, 
in  a  distance  of  i  fathom  (6  feet)  measured  along  the  dip.  Thus 

and  1039.  The  Richmond  Mining  Company  of  Nevada  v.  The  Eureka  Con- 
solidated Mining  Company.  Appeal  from  the  Circuit  Court  of  the  United 
States  for  the  district  of  Nevada,  p.  604.  Filed  January  17,  1878. 

*  "The  Aspen  Case,"  Eng.  Mln.  Jour.     New  York,  vol.  xliii.  1887,  p.  21. 

t  "  The  Smuggler  Case,"  op.  cit.  p.  20. 


10 


ORE  AND  STONE-MINING. 


if  AB  (Fig.  5)  represents  a  lode,  and  AC  =  6  feet,  AD  being  verti- 
cal, draw  the  line  CE  at  right  angles  to  AD,  the  inclination  is 
measured  by  the  relation  of  EC  to  AC. 

If  EC  =  2  feet  the  underlie  is  said  to  be  2  feet  in  a  fathom. 
This  approaches  very  closely  to  a  dip  of  70°,  or 
FIG.  5.  underlie  of  20°,  whilst  i  foot  in  a  fathom,  for  most 
practical  purposes,  corresponds  to  a  dip  of  80°,  or 
underlie  of  10°.  This  method  of  expressing  the  dip 
enables  it  to  be  determined  with  a  rule  or  tape.  If 
AB  (Fig.  6)  is  a  lode  at  the  end  of  a  mining  tunnel 
(level),  the  miner  has  simply  to  measure  the  distance 
EC  =  6  feet,  drop  a  stone  from  C  and  ascertain  the 
distance  from  D,  where  it  falls,  to  E.  However, 
there  is  the  disadvantage  that  some  miners  take  the 
standard  fathom  vertically  and  not  along  the  dip  ; 
therefore,  to  avoid  any  chance  of  confusion  it  is 
wiser  to  express  the  inclination  of  veins  in  degrees, 
and  not  by  "  feet  in  a  fathom." 

The  bounding  planes  of  a  vein,  VY  (Fig.  7),  are  called  the  walls 
or  cheeks,  and  they  are  frequently  smooth  and  striated,  showing  that 
one  side  must  have  slid  against  the  other.  These  striated  surfaces 
are  called  slickensides.  At  the  Halkyn  mine,  Flintshire,  the 
whole  side  of  one  of  the  levels,  for  a  distance  of  ten  yards,  is  a 
smooth  flat  polished  surface,  with  small  striae,  precisely  like  the 
scratchings  produced  upon  rocks  by  the  action  of  glaciers.  In 
this  particular  case  the  striations  are  horizontal ;  more  frequently 
they  are  inclined.  The  wall  above  a  lode  is  called  the  hanging 


wall,  AB,  the  one  underneath,  the  foot  ivall,  CD.  The  rock 
surrounding  or  enclosing  the  lode  is  called  the  country,  EE.  I 
give  this  term,  not  because  I  wish  to  perpetuate  a  mere  Cornish 
provincialism,  but  because  it  has  crept  into  use  elsewhere.  To 
use  the  words  country  rock,  as  is  done  very  frequently,  is  to  be 
guilty  of  tautology.  I  may  here  remark,  once  for  all,  that,  as  a 
general  rule,  it  is  best  to  avoid  local  technical  terms,  and  as  far  as 
possible  employ  words  which  are  understood  by  every  one ;  but 


MODE  OF  OCCURRENCE  OF  MINERALS.  n 

some  expressions  are  so  convenient  on  account  of  their  brevity 
that  they  may  fairly  be  adopted  into  our  language.  It  is  not  un- 
common to  find  a  layer  of  clay,  FG,  between  the  lode  and  the 
enclosing  rocks  ;  such  a  layer  is  called  a  selvage,  dig  (Cornwall), 
gouge  (U.S.),  or  alta  (California).  A  large  mass  of  the  adjacent 
rock  found  enclosed  in  the  lode  is  called  a  horse,  HH. 

The  valueless  components  of  a  lode  which  surround  the  ore  are 
often  spoken  of  as  forming  the  gangue.  I  mention  the  word  in 
order  to  enter  a  protest  against  its  use,  because,  in  its  passage  to 
us  from  the  German  through  the  French,  it  has  lost  part  of  its 
original  meaning.  We  already  have  the  words  veinstone,  lode- 
sty  ff,  and  matrix,  which  are  more  strictly  correct  and  more  easily 
understood  than  gangue,  which,  by  Englishmen,  should  be  con- 
signed to  oblivion. 

Veins  often  continue  for  a  great  distance  along  their  strike. 
The  Van  lode  in  Montgomeryshire  is  known  for  a  length  of  nine 
miles,  whilst  the  Great  Quartz  Vein  in  California  has  been  traced 
for  a  distance  of  no  less  than  eighty  miles. 

Veins  are  of  less  uniform  productiveness  than  beds,  and  are 
rarely  worth  working  through- 
out.     Rich   portions   alternate  FIG.  8. 

with  poor  or  worthless  portions.         SU*™C.J^N, — — — . . . — 3? — 

The   rich  parts   have    received        A°'T  *ty'L^-.:.f$$>»         ../       +££ 
various  names  according  to  the     - '°  ""^^^ff!^-^  c,.*f       '%&?" 
forms  they  assume  :    Fig.  8  re-       ™a  ^^•'•'^f^^ff  .^'  jft\  ^tfj? 
presents  a  longitudinal   section 
along  the  strike  of  a  lode,  and 
the  stippled  parts  are  ore-bodies.      '  tor.™...  L^™.    o^'       ~*^B 
BBB  are  bunches  ;  A  is  a  large 

bunch  or  course  of  ore ;  when  an  ore-body  forms  a  sort  of  con- 
tinuous column  we  have  a  shoot  (chute, ~U.$.}.  Ore-bodies  which  upon 
being  excavated  leave  chimney -like  openings  are  called  pipes  (C). 
In  the  United  States  the  Spanish  word  bonanza,  literally  meaning 
"  fair  weather "  or  "  prosperity,"  is  frequently  used  for  a  rich 
body  of  ore.  The  inclination  of  a  shoot  in  the  direction  of  the 
strike  is  called  its  pitch  and  sometimes  its  dip,  though  it  is  better 
to  restrict  this  word  to  the  meaning  it  receives  among  geologists. 

It  is  of  the  utmost  importance  to  the  miner  to  know  where  he 
may  expect  to  find  a  rich  ore-body  in  a  mineral  vein.  Experience 
shows  that  many  conditions  affect  its  productiveness,*  viz. : — 

1.  Intersections  with  other  veins. 

2.  Nature  of  the  adjacent  rock. 

3.  Change  of  dip. 

4.  Change  of  strike. 

*  See  also,  L.  Moissenet,  Observations  on  the  Rich  Part*  of  the  Lodes  of 
Cornwall.  Translated  from  the  French  by  J.  H.  Collins.  London  and 
Truro,  1877. 


12 


ORE  AND  STONE-MIXING. 


(1)  Intersections  of  veins. — AB  (Fig.  9)  is  a  vein  intersecting 
another  CD  at  an  acute  angle  AEG  ;  it  is  frequently  the  case  that 
there  is  an  enrichment  about  the  junction  E.     If  the  lines  A'B', 

C'D'  represent    the    lodes  at  a  lower 
FIG.  9.  level,   then  EE'    indicates   the  line  of 

intersection,  which  may  be  the  axis  of 
a  shoot  of  ore  upon  one  of  them  ;  but 
;-  ^^^^      ~  when  the  angle  AEG  approaches  a  right 
i  "^ — o    angle   a   favourable   result   is   not  ex- 

c'. .  ^  i  pected. 

r.V--^. .. .  g-  If  AB  (Fig.  i  o)  represents  a  section 

of  a  lode  along  the  dip,  and  CD,  EF. 
and  GH  are  small  veins  (feeders,  drop- 
pers) falling  into  it,  an  increase  in  the 
productiveness  of  the  lode  often  occurs  near  the  intersection. 

(2)  Nature  of  the  adjacent  rock. — Few  facts  are  more  generally 
recognised  than  the  influence  of  the  enclosing  rock  upon  the 
productiveness  of  a  lode.     I  will  cite  some  well-known  examples. 
In  the  Alston  Moor  district  the  veins  cross  alternating  beds  of 
limestone,  sandstone,  and  shale;   they  are  generally  more  pro- 
ductive in  the  limestone  than  in  the  sandstone  or  the  shale. 

At  Kongsberg,  in  Norway,  the  silver  veins  are  productive  in  the 


-D* 


FIG.  10. 


FIG.  ii. 


fahlbands,  that  is  to  say,  quartz  schist,  mica  schist,  hornblende 
schist,  and  chlorite  schist  impregnated  with  iron  pyrites  and  other 
metallic  sulphides,  but  are  poor  where  they  cross  the  gneiss.  The 
lines  ABand  CD  in  Fig.  n  represent  two  such  veins  in  plan;  the 
portions  ab  and  cd  are  worth  working,  but  the  other  parts  are  not. 


MODE  OF  OCCURRENCE  OF  MINERALS.          13 

In  the  Gympie*  gold  field,  Queensland,  the  veins  are  richest 
in  certain  bands  of  black  shale.  Four  principal  belts  of  black 
shale  have  been  recognised,  and  their  influence  is  so  thoroughly 
known  that  "  the  fact  has  determined  the  system  of  mining  on 
the  field." 

Turning  to  another  part  of  Australia,  we  may  notice  the 
"  indicators "  at  Ballarat.f  These  are  narrow  beds,  some  only 
£  inch  thick,  parallel  to  the  planes  of  stratification  of  the 
enclosing  slate,  and  full  of  small  cubical  crystals  of  iron  pyrites. 
Their  dip  is  nearly  vertical,  and  they  can  be  traced  for  miles. 
When  a  quartz  vein  crosses  an  "  indicator  "  there  is  usually  rich 
gold  along  the  line  of  intersection.  Mr.  Charles  King  says: 
"  About  ten  of  these  '  indicators  '  are  known  within  a  width  east 
and  west  of  1,400  feet,  and  in  the  case  of  six  out  of  these,  the 
quartz  crossing  them  contains,  at  the  line  of  intersection,  exceed- 
ingly rich  patches  of  gold,  frequently  in  nuggets  many  ounces  in 
weight."  Why  only  six  out  of  the  ten  indicators  should  have  the 
enriching  effect  is  not  stated. 

A  third  instance  of  the  enriching  effect  of  a  pyritiferous  rock 
is  afforded  in  the  Thamesf  gold-field  of  New  Zealand,  where, 
instead  of  a  narrow  "  indicator,"  there  is  a  marked  belt  of  rock, 
60  to  80  feet  thick,  in  which  the  veins  prove  remunerative.  This 
"  congenial  "  bed  is  a  felspathic  sandstone  containing  pyrites,  and 
is  probably  a  volcanic  ash.  The  veins  are  poor,  or  die  out 
altogether  011  entering  the  harder  diorite  or  underlying  slate. 

Even  in  the  case  of  earthy  minerals  the  same  phenomenon 
occurs.  At  Wotherton  mine,  in  Shropshire,  the  barytes  vein  is 
wide  and  worth  working  when  the  adjacent  rock  is  volcanic  ash, 
but  narrow  and  valueless  in  shale. 

Lead  veins  in  Derbyshire,  which  are  productive  in  limestone, 
rarely  yield  much  ore  in  the  loadstone,  an  interbedded  lava. 

(3)  Change   of   dip. — In  a,  given  vein  the  parts  approaching 
verticality  are  often  noticed  to  be  richer  than  those  which  are 
comparatively  flat. 

(4)  Change  of  strike. — The  veins  of  a  mining  district  are  com- 
monly found  to  have  the 

same  prevailing  strike.  FIG.  12. 

Thus  the  tin  and  copper 

lodes  of  the   Camborne 

and  Redruth   districts, 

Cornwall, §  usually  run  from  S.S.W.  to  N.N.E.,  and  are  spoken  of 

*  K.  L.  Jack,  Annual  Report  of  the  Department  of  Mines,  Queensland,  for 
the  year  1885.  Brisbane,  1886,  p.  58. 

t  C.  Le  Neve  Foster,  "  Mining  Industries,"  Reports  on  the  Colonial  Sec- 
tions of  the  Exhibition.  London,  1887,  p.  18. 

$  OP.  at.  P.  35. 

§  Kenwood,  "  On  the  Metalliferous  Deposits  of  Cornwall  and  Devon," 
Trans.  11.  Geol.  Soc.  Com.  Penzance,  1843,  vo1-  v-  P-  250. 


14  ORE  AND  STONE-MINING. 

as  east  and  west  lodes.  Slight  changes  in  the  direction  of  the 
strike  are  sometimes  followed  by  variations  in  the  productive- 
ness ;  in  the  case  of  a  lode  with  an  average  strike  repre- 
sented by  the  dotted  line  a  b,  it  may  happen  that  the  parallel 
parts  a  b,  c  d,  ef,  are  poor,  and  the  parallel  parts  b  c  and  d  e 
rich*  (Fig.  12). 

Too  much  stress  must  not  be  laid  upon  this  question  of  strike, 
because  there  are  so  many  exceptions  to  the  rule  that  a  certain 
strike  is  favourable.  For  instance,  the  two  principal  mines  in 
the  Isle  of  Man,  Laxey  and  Foxdale,  are  wrought,  one  upon  a 
north  and  south  vein,  the  other  upon  an  east  and  west  vein,  only 
a  few  miles  apart ;  and  at  St.  Just,  in  the  extreme  west  of  Corn- 
wall, the  mean  direction  of  the  lodes  is  35°  N.  of  W.,  and  there- 
fore quite  different  from  what  it  is  in  the  chief  metalliferous 
region ;  but  with  individual  lodes  changes  of  strike  should  not 
pass  unnoticed. 

Formation  of  Mineral  Veins. — Though  this  book  is  intended 
to  deal  mainly  with  the  working  of  mines,  a  few  remarks  con- 
cerning the  origin  of  veins  are  necessary — first,  because  the 
posteriority  of  their  formation  is  one  of  their  chief  characteristics ; 
and,  secondly,  because  a  knowledge  of  the  manner  in  which  useful 
minerals  came  to  be  concentrated  along  certain  lines  may  enable 
us  some  day  to  predict  the  precise  spots  where  subterranean  riches 
are  accumulated. 

The  principal  theories  are ; 

1 .  Fracture  and  motion  with  mechanical  filling. 

2.  Fracture  and  injection  of  molten  matter. 

C  (a)  from  above. 

3.  Fracture  and  deposition  from  solutions  -j    (b)  from  below. 

(   (c)  from  the  sides. 

4.  Fracture  and  sublimation,  or  deposition  from  gases. 

(1)  Mechanical  Filling. — If  a  rock  is  fractured,  and  one  side 
of  the  crack  slides  against  the  other,  a  vein  of  crushed  material  is 
formed.     If  the  rock  is  shale  or  slate,  the  vein  is  a  band  of  clay 
more  or  less  mixed  with  uncrushed  fragments,  and  in  Cornwall  is 
known  as  a,jlookan. 

(2)  Injection. — Veins  formed  by  the  injection  of  a  molten  or 
plastic  rock  into  fissures  are  usually  known  as  dykes. 

(3)  Deposition  from  Solution. — The  lode  at  Wheal  Mary  Ann, 
Cornwall  (Fig.  2),  is  an  instance  of  a  vein  formed  apparently  by 
deposition  from  solution.     Many  of  the  common  constituents  of 
mineral  veins,  such  as  silica,  carbonate  of  calcium,  sulphate  of 
barium,  are   known  to  be  slightly  soluble  in  water,  whilst  the 
metallic  sulphides  can  be  formed  by  the  reduction  of  a  soluble 
sulphate,  or  by  the  reaction  of  a  soluble  sulphide  or  sulphuretted 

*  Charles  Thomas,  Remarks  on  tJie  Geology  of  Cornwall  and  Devon.  Red- 
ruth,  1859,  p.  5. 


MODE  OF  OCCURRENCE  OF  MINERALS.          15 

hydrogen  upon  metallic  compounds.  Some  metallic  sulphides  are 
soluble  in  alkaline  solutions. 

Much  discussion  has  arisen  concerning  the  place  whence  the 
mineral-bearing  solutions  came.  The  theory  that  they  came 
from  above  finds  few  upholders  nowadays,  and  the  battle  rages 
principally  between  the  advocates  of  the  ascensional  theory,  or 
supposition  that  the  minerals  came  up  in  solution  from  very 
great  depths,  and  the  upholders  of  the  lateral  secretion  theory, 
in  which  it  is  assumed  that  they  were  leached  out  of  the  adjacent 
rocks  and  re- deposited  in  the  vein  cavity.  This  latter  theory  has 
been  powerfully  espoused  of  late  years  by  Professor  Fridolin  von 
Sandberger,*  who  has  pursued  his  investigations  with  great 
ardour.  He  shows  that  small  quantities  of  antimony,  arsenic, 
bismuth,  cobalt,  copper,  lead,  silver,  and  tin  are  contained  in 
silicates  such  as  augite,  hornblende,  mica,  and  olivine,  which  are 
essential  constituents  of  plutonic  and  volcanic  rocks ;  and  he 
concludes  that  these  rocks  are  the  sources  from  which  the  lodes 
have  derived  their  riches. 

Prof,  von  Sandberger's  views  have  not  been  allowed  to  pass 
unchallenged,  for  Prof.  Alfred  Stelznerf  combats  his  methods  of 
analysis. 

It  is  naturally  impossible  to  affirm  with  certainty  that  a  given 
mineral,  such  as  mica,  contains  lead  for  instance,  so  long  as  there 
is  a  possibility  that  particles  of  galena  were  mixed  with  it.  The 
absolute  freedom  of  the  rocks  submitted  to  analysis,  from  any 
mechanical  admixture  with  pyrites  or  other  sulphides  is  a  neces- 
sary foundation-stone  of  von  Sandberger's  theory.  It  is  against 
this  point  that  Professor  Stelzner  directs  his  attack,  and  he  shows, 
by  the  results  of  numerous  carefully  conducted  experiments,  that 
the  metals  found  on  analysis  by  Professor  von  Sandberger  did  not 
necessarily  come  from  the  silicates,  but  may  have  been  derived 
from  mechanically  mixed  sulphides  which  had  resisted  his 
attempts  to  remove  them.  Stelzner  points  out  that  the  occurrence 
in  the  country  of  sulphides,  similar  to  those  existing  in  the  lodes, 
may  be  explained  quite  as  well  by  their  having  travelled  from  the 
fissure  into  the  adjacent  rock,  as  in  the  reverse  direction. 

With  reference  to  the  silver  found  in  the  rocks,  Stelzner  re- 
marks that  the  mica  of  granite  at  Sulzbachle  in  the  Black  Forest, 
stated  by  von  Sandberger  and  others  to  contain  o'ooi  to  0*006 
per  cent,  of  silver,  was  found  to  be  absolutely  free  from  any 
traces  of  the  metal  when  assayed  with  special  precautions  at  the 
Mining  College  of  Freiberg. 

Under  these  circumstances  von  Sandberger's  theories  must  for 
the  present  be  looked  upon  as  not  entirely  proven,  much  as  one 

*   Untersuckungen  iiber  Erzyange.     Wiesbaden,  1882  and  1885. 

t  "  Die  Lateralsecretions-Theorie  und  ihre  Bedeutung  fiir  daa  Pribramer 
Ganggebiet,"  Jahrbuch  der  k.k.  Bergakademieu  zu  Leoben  und  Pribram  und 
der  kgl.  ung.  JBergalcademie  zu  /Schemnitz,  vol.  xxxvii. 


1 6  ORE  AND  STONE-MINING. 

would  like  to  be  able  to  account  in  so  direct  a  manner  for  the  in- 
fluence of  the  country  upon  the  contents  of  the  lodes. 

The  views  of  Mr.  Becker,*  with  reference  to  the  quicksilver 
mines  of  California  and  Nevada,  deserve  special  mention,  because 
the  adherents  of  both  parties  will  probably  claim  them  as  support- 
ing their  theories.  To  avoid  any  chance  of  mistake,  I  quote  ver- 
batim :  "  The  evidence  is  overwhelmingly  in  favour  of  the  supposi- 
tion that  the  cinnabar,  pyrites,  and  gold  of  the  quicksilver  mines 
of  the  Pacific  slope  reached  their  present  positions  in  hot  solutions 
of  double  sulphides,  which  were  leached  out  from  masses  under- 
lying the  granite  or  from  the  granite  itself."  Mr.  Becker 
supposes  that  the  hot  alkaline  solutions  were  the  products  of 
volcanic  agencies,  and  he  decidedly  leans  to  the  view  that  they 
took  up  the  heavy  metals  in  their  passage  through  the  granite 
itself,  and  not  from  rocks  underlying  it. 

Even  if  the  ore  was  not  leached  out  of  the  immediately  adjacent 
rocks,  these  may  have  influenced  its  deposition  either  chemically 
or  mechanically.  It  is  possible  that  a  certain  bed  may  act  as 
a  reducing  agent  upon  a  solution  which  touches  it,  and  so  cause 
precipitation ;  this  may  be  the  reason  why  rich  gold  has  been 
deposited  where  the  pyritiferous  "indicators"  intersect  the 
Ballarat  lodes.  The  mechanical  effect  is  also  very  simple.  A  fissure 
formed  in  a  soft  rock  is  likely  to  be  filled  up  by  pieces  of  the 
sides  dropping  in,  especially  if  there  is  any  sliding  of  the  hanging 
wall  upon  the  foot  wall ;  on  the  other  hand,  if  the  rock  is  hard, 
the  chasm  will  remain  open  and  leave  a  space  for  the  reception 
of  ores.  This  fact  gives  a  reason  for  the  steep  parts  of  lodes  being 
sometimes  richer  than  the  flatter  parts.  If  a  wavy  cut  is  made 
in  a  piece  of  card  or  paper  to  represent  the  fissure,  and  the 
"  hanging  wall "  slid  down  a  little,  we  have  open  spaces  where 
the  fissure  is  steep,  whilst  the  "  walls  "  touch  where  the  fissure  is 
flatter,  leaving  no  room  for  any  deposition  of  ore  to  take  place. 
A  wavy  crack  of  this  kind  may  be  caused  by  variations  of  hard- 
ness and  fissility,  such  as  happen  when  shale  is  interbedded  with 
limestone ;  here  the  crack  will  be  propagated  more  readily  along 
the  planes  of  stratification  of  the  shale  than  across  them.  After 
a  slight  shift  of  the  "  hanging  wall "  downwards,  the  cavities  in 
the  limestone  become  receptacles  for  mineral  deposits,  whilst  the 
crack  contains  little  but  crushed  rock  in  the  shale. 

In  a  like  manner  the  variation  in  productiveness  noticed  upon 
a  slight  alteration  of  strike  may  be  due  to  change  in  the  nature 
of  the  "  country,"  which  not  only  caused  a  deviation  from  the 
general  direction  of  the  fissure,  but  also  affected  its  ore-bearing 
qualities.  Here,  too,  we  find  an  explanation  of  the  phenomenon 
called  "ore  against  ore."  In  Fig.  13  let  ABCD,  and  EFGH 

*  "Geology  of  the  Quicksilver  Mines  of  the  Pacific  Slope,"  Monographs 
of  the  U.S.  Geol.  tiurvey,  vol.  xiii.  p.  449.  Washington,  1888. 


MODE  OF  OCCURRENCE  OF  MINERALS.          17 

represent  a  plan  of  two  parallel  lodes,  BC  and  FG  being  rich  parts ; 

the  miner  notices  that  an  improvement  in  the  productiveness  takes 

place  in  both  lodes  when  the  strike  changes  from  E.  and  W.  to  E. 

25°  N.,  and  that  the  rich  part,  BC,  is  opposite  the  rich  part  FG. 

This  is  not  surprising  if  the  parts  BC  and  FG  are  in  a  special  belt 

or     zone,    included 

between    the    lines  FIG.  13. 

HK,   LM,    capable  > 

of  exerting  either  a  ,  \ 

mechanical       effect  H  \  \ 

upon  the  size  of  the 

vein-cavity    by    its 

hardness,     or     a 

chemical    effect    by 

its  composition. 

The  adjacent  rock 
may  likewise  have 
affected  the  lode  by 
its  porosity  or  by  its 
impermeability,  in 
the  former  case  by 
affording  an  easy  channel  for  the  solutions  which  brought  in  the 
minerals,  and  in  the  latter  by  interposing  a  dam  which  prevented 
or  delayed  their  escape. 

(4)  Sublimation. — The  sublimation  theory  meets  with  little 
favour  nowadays,  though  certain  minerals  known  as  constituents 
of  lodes  are  formed  in  furnaces,  or  can  be  produced  artificially 
from  gases.  Nearly  half  a  century  ago,  Daubree  *  produced 
crystals  of  oxide  of  tin  by  passing  a  current  of  stannic  chloride 
together  with  steam  through  a  red-hot  porcelain  tube.  One  great 
objection  to  the  universal  acceptance  of  the  sublimation  theory  is 
that  many  of  the  minerals  found  in  lodes  would  be  decomposed  at 
high  temperatures. 

Formations. — The  lodes  in  some  districts  are  grouped  into 
different  classes  according  to  their  mineralogical  characters,  and 
careful  observations  have  shown  that  those  which  are  similar  in 
mineral  contents  usually  agree  in  strike  and  in  age.  Distinctions 
of  this  kind  have  been  skilfully  worked  out  at  Freiberg  f  in 
Saxony,  where  six  of  these  classes  or  "  formations  "  are  recognised. 

Anomalies. — It  must  be  understood  that  we  cannot  expect  Nature 
to  make  distinct  lines  of  demarcation  between  the  different  kinds  of 
mineral  repositories.  Though  we  may  be  able  to  see  clearly  that 

*  "  Kecherches  sur  la  production  artificielle  de  quelques  especes  minerales 
cristallines,  particulierement  de  1'oxyde  d'etain,  de  1'oxyde  de  titane  et  da 
quartz.  Observations  sur  1'origine  des  filons  titaniferes  des  Alpes,"  Ann. 
Mines,  46  serie,  vol.  xvi,  1849,  p.  129.  Compt.  Rend.,  vol.  xxix.  1849, 
p.  227,  and  vol.  xxx.  1850,  p.  383. 

t  Freibergs  Berg-  und  Hiittenwesen.     Freiberg  i.  S.,  1893,  p.  32. 

B 


i8  ORE  AND  STONE-MINING. 

a  seam  of  coal  is  contemporaneous  with  the  enclosing  rocks,  and 
that  a  vein,  intersecting  successively  beds  of  limestone,  shale,  and 
sandstone,  is  evidently  of  later  formation,  cases  frequently  occur 
in  which  the  origin  of  the  mineral  is  uncertain. 

For  example  we  have  the  lead-bearing  sandstone  of  Mechernich, 
the  silver -bearing  sandstone  of  Utah,  the  gold-bearing  conglomerate 
of  the  Transvaal.  The  grains  of  sand  and  the  pebbles  of  quartz 
are  unquestionably  of  sedimentary  origin ;  but  opinions  differ 
as  to  whether  the  lead,  silver,  and  gold  were  deposited  originally 
with  the  sand  and  gravel,  or  were  introduced  subsequently  by 
metal-bearing  solutions,  which  found  a  passage  through  the  beds. 
It  has  been  shown  by  Mr.  Becker*  that  ample  space  exists  in  an 
ordinary  sandstone  for  the  deposition  of  ores.  Supposing  that 
all  the  grains  were  true  spheres  of  the  same  size,  and  as  closely 
packed  together  as  possible,  there  would  be  26  per  cent,  of  inter- 
stitial space.  If  this  space  is  even  partly  occupied  by  an  ore,  the 
percentage  of  metal  may  very  easily  be  sufficient  to  render  the 
stratum  worth  working.  For  example,  a  sandstone  with  a  specific 
gravity  of  2*25  requires  only  3-7  per  cent,  of  its  interstitial  space 
to  be  filled  by  cinnabar  with  a  specific  gravity  of  8,  in  order  to 
furnish  an  ore  with  10  per  cent,  of  mercury,  about  the  average 
contents  of  the  rock  worked  at  Almaden.  This  3*7  per  cent,  is  "  less 
than  half  the  interstitial  space  in  some  indurated  sandstones 
employed  for  paving  streets."  In  the  case  of  sandstones  worked 
for  mercury,  it  seems  to  be  quite  certain  that  the  cinnabar  was 
brought  in  by  aqueous  solutions  long  after  the  deposition  of  the 
sediment — indeed,  long  after  the  solidification  and  upheaval  of 
the  rocks. 

According  to  Dr.  Sorby,  the  iron  of  the  well-known  Cleveland 
bed  was  "  derived  partly  from  mechanical  deposition  and  partly 
from  subsequent  replacement  of  the  originally  deposited  car- 
bonate of  lime."f 

Other  cases  of  more  or  less  complete  replacement  may  be  cited. 
We  find  chalk  changed  into  flint,  limestone  into  chert;  and  if 
"  subsequent  origin  "  were  the  only  characteristic  distinguishing  a 
vein  from  a  bed,  we  should  be  landed  in  a  difficulty.  It  will  be 
found  convenient  to  consider  as  seams  any  stratified  deposits  in 
which  the  impregnated,  altered,  or  pseudomorphous  mass  occupies 
the  position  of  an  original  bed,  and  to  call  the  sheets  veins  when 
they  cross  the  bedding-planes,  or  occupy  a  fissure,  or  have  been 
formed  by  the  alteration  of  a  rock  at  the  side  of  a  fissure. 

MASSES. — These  are  deposits  of  mineral,  often  irregular  in 
shape,  which  cannot  be  distinctly  recognised  as  beds  or  veins. 
Such,  for  instance,  are  certain  of  the  red  haematite  deposits  of 

*  "  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope,"  Monographs 
of  the  U.S.  Geol.  Survey,  vol.  xiii.  p.  399.  Washington,  1888. 

t  Quart.  Jour.  Geol.  Soc.,  vol.  xxxv.,  1879,  p.  85.  Anniversary  Address 
of  the  President. 


MODE  OF  OCCURRENCE  OF  MINERALS.  19 

the  Ulverston  district  (Fig.  14),*  which  occupy  irregular  cavities 
in  the  Carboniferous  Limestone.     They  may  have  been  formed 

FIG.  14. 


A,  the  enclosing  limestone  ;  B,  red  haematite  ;  C,  sand  and  clay : 
D,  a  thick  capping  of  glacial  drift. 

by  the  percolation  of  water  Bringing  down  iron  in  solution  from 
overlying  rocks,  which  by  gradual  replacement  changed  part  of 
the  limestone  into  a  mass  of  haematite.  Other  examples  of  masses 
are  the  calamine  deposits  of  Altenberg  (Fig,  15),!  Sardinia,  and 


FIG.  15. 


FIG.  1 6. 


B,   the  enclosing    slate,   d, 
dolomite,  C,  calamine,  L,  clay. 


Scale  *i.  Tin=iff 

=i  2  Sleet 


Mulberry  Mine,  near  Bodmin. 

Lombardy,  the  huge  upright  "  necks "  or  "  pipes "  of  diamond- 
bearing  rock  in  South  Africa,  and  the  granite  decomposed  in  situ 
worked  for  china  clay  in  Cornwall. 

Under  this  head  also  are  included  by  most  authors  the  so-called 
"  stockworks,"  "  reticulated  masses  "  or  "  network  deposits," 
names  applied  to  masses  of  rock  intersected  by  so  many  little 
veins  as  to  make  the  whole  worth  excavating. 

Fig.  1 6  shows  a  number  of  steeply  dipping  strings  of  cassi-. 
terite,  generally  only  two  or  three  inches  apart,  intersecting  beds 

*  "Beschreibung  der  Rotheisenerzlagerstiitten  von  West  Cumberland 
und  North  Lancashire,"  Stahl  und  Eisen,  2  Jahrgang,  No.  12,  Plate  VI. 

t  M.  Braun,  Zeitschr.  d.  d.  geol.  GesellscJi.,  vol.  ix.  (1857) ;  and  A.  von 
•Groddeck,  Die  Lelire  von  den  Lagerstcitten  der  Erze.  Leipsic,  1879,  p.  242. 


20  ORE  AND  STONE-MINING. 

of  slate.  The  mass  of  rock  penetrated  by  this  network  of  little 
tin  veins  is  300  yards  long  by  more  than  30  yards  wide,  and  the 
whole  of  the  stanniferous  stone  is  quarried  and  stamped.* 

EXAMPLES. — These  abstract  definitions  are  not  sufficient ; 
the  student  should  see  how  they  can  be  applied  to  particular  cases  ; 
and  I  now  propose  to  give  a  series  of  examples  of  the  modes  of 
occurrence  of  the  most  important  minerals.  As  the  same  mineral 
may  be  found  in  a  bed,  a  vein,  or  a  mass,  it  is  simplest,  for  the 
purposes  of  the  miner,  to  classify  these  examples  alphabetically. 
I  therefore  arrange  the  information  about  tin,  for  instance,  under 
one  head,  instead  of  separating  the  tin  veins  from  the  stockworks, 
and  these  from  the  alluvia.  The  minerals  to  which  I  propose  to 
refer  are : 

Alum,  amber,  antimony  ore,  arsenic,  asbestos,  asphalt, 
barytes,  borax,  boric  acid,  carbonic  acid,  clay  (including  china 
clay,  fire  clay,  fuller's  earth,  potter's  clay),  cobalt  ore,  copper  ore, 
diamonds,  flint,  freestone,  gold,  graphite,  gypsum,  ice,  iron  ore, 
iron  pyrites,  lead  ore,  manganese  ore,  nitrate  of  soda,  ochre,  oil 
shale,  ozokerite,  petroleum,  phosphate  of  lime,  potassium  salts, 
quicksilver  ore,  salt,  silver  ore,  slate,  stone,  strontium  sulphate, 
sulphur,  tin  ore,  zinc  ore. 

Alum. — The  alum-stonet  obtained  at  Allumiere  and  Tolfa,  near 
Civita  Vecchia,  occurs  in  very  irregular  veins,  which  are  supposed 
to  be  due  to  the  action  of  heated  water  and  sulphurous  gases  upon 
the  felspar  contained  in  trachyte. 

An  important  deposit  of  alunite  has  lately  been  discovered^: 
in  New  South  Wales,  at  the  Bullahdelah  Mountain,  which 
rises  up  from  the  bank  of  the  Myall  River,  a  tributary  of 
Port  Stephens.  Marked  cliffs,  overlooking  the  river,  consist  of 
alunite  in  varying  quality,  ranging  from  pure  alunite  to  a  mineral 
in  which  there  is  as  much  as  40  per  cent,  of  silica.  The  deposit 
is  traced  for  over  a  mile  in  length  and  nearly  three-quarters  of  a 
mile  in  breadth,  the  thickest  band  of  stone  being  from  60  to  70 
yards  in  width.  The  average  composition  of  the  rock  now  being 
worked  is  as  follows  : 

•  Per  cent. 

Water ,  7-80 

Alumina ,  34'7o 

Oxide  of  iron  ......  i  'oo 

Potash 6-10 

Sulphuric  acid 32-30 

Silica  .  .         .  18-10 


lOO'OO 

*  C.  Le  Neve  Foster,  "  On  some  Tin  Stockworks  in  Cornwall,"  Quart. 
Jour.  Geol.  Soc.,  vol.  xxxiv.,  1878,  p.  655. 

t  A.  K,  de  la  Grange,  Le  Tracliiti  ddla  Tolfa  e  le  formazioni  attuminifere. 
Rome,  1 88 1. 

t  MS.  information  from  Mr.  S.  Herbert  Cox,  A.R.S.M,,  the  discoverer  of 
the  alunite. 


MODE  OF  OCCURRENCE  OF  MINERALS.          21 

The  surrounding  rocks  belong  to  the  Carboniferous  system  of 
New  South  Wales,  and  it  is  supposed  that  the  alunite  has  been 
formed  by  solfataric  action  upon  dykes  of  a  felsitic  rock. 

Amber. — This  fossil  resin  is  found  in  a  bed  of  Tertiary  age, 
which  extends  along  the  shores  of  the  Baltic  from  Western 
Russia  to  Denmark.  The  principal  workings  are  about  halfway 
between  Memel  and  Dantzig,  and  the  amber  is  obtained  by  diving 
and  dredging  in  the  sea  and  by  ordinary  mining  inland.  After  a 
storm  pieces  are  cast  up  on  the  shore.  The  stratum  containing 
the  amber  is  known  from  its  colour  as  the  "  blue  earth." 

Antimony.— Antimony  ore  usually  occurs  in  veins.  In  York 
County,  New  Brunswick,*  the  veins  are  from  a  few  inches  to 
6  feet  wide  in  Lower  Silurian  slate.  The  veinstone  is  white 
quartz,  calcite,  and  iron  pyrites  in  small  crystals.  The  ore  raised 
from  the  mine  contains  about  10  per  cent,  of  stibnite. 

Arsenic. — The  white  arsenic  of  commerce  is  mainly  obtained 
from  mispickel,  which  is  either  mined  by  itself  or  more  commonly 
in  connection  with  the  ores  of  copper,  tin,  or  gold.  It  is  there- 
fore in  most  cases  a  by-product  in  the  preparation  of  these  ores 
for  the  market. 

Asbestos. — The  asbestos  of  commerce  is  in  part  chrysotile  and 
in  part  the  fibrous  variety  of  hornblende.  Italy  and  Canada  are  the 
chief  sources  of  supply,  and  in  both  countries  the  mineral  is  found 
in  veins  in  serpentine.  The  principal  Italian  mines  are  in  the  Susa 
and  Aosta  valleys  and  the  Yaltellina.f  In  one  of  the  mines  in 
a  tributary  of  the  latter  valley  the  rock  is  "  cut  in  every  direction 
by  thin  seams  of  asbestos,  which  seem  to  start  as  from  a  centre 
and  spread  out  in  every  direction,  and  these  again  are  traversed 
by  thin  seams  both  horizontally  and  diagonally.  Entering  into 
the  rock,  these  seams  generally  converge  to  a  centre,  where 
the  various  thin  seams  unite  themselves,  and  here  a  pocket  of  a 
ton  or  a  ton  and  a  half  of  asbestos  may  be  found,  and  then  all 
appearance  of  its  presence  ceases.  Continuing  to  work  inwards, 
the  seams  generally  re-appear  and  spread  themselves  out  as 
before." 

The  most  important  of  the  Canadian  quarries  are  situated  in 
the  townships  of  Thetford  and  Coleraine,  in  the  province  of 
Quebec.  A  belt  of  serpentine  runs  through  the  district,  and  it  is 
intersected  by  innumerable  small  veins  of  chrysotile,  varying  in 
width  from  a  mere  knife-edge  to  about  6  inches  at  the  most, 
the  fibres  of  the  mineral  running  almost  at  right  angles  to  the 
walls.  The  common  width  of  the  veins  is  from  i  to  2  inches,  and 
as  they  "cross  and  recross  each  other  in  every  direction  and  at 

*  E.  M.  J.,  vol.  xvi.,  1873,  P-  7  J  and  B.  u.  h.  Z.  1874,  p.  237. 

t  James  Boyd,  "Asbestos  and  its  Applications,"  Jour.  Soc.  Arts, 
vol.  xxxiv.  (1886),  p,  583.  J.  A.  Fisher,  "Mining,  Manufacture  and  Uses 
of  Asbestos,"  Trans.  List.  Marine  Eng.,  vol.  iv.,  1892. 


22  ORE  AND  STONE-MINING. 

every  angle,"  *  the  whole  of  the  enclosing  rock  has  to  be  quarried 
in  order  to  get  out  the  asbestos. 

Asphalt. — The  various  modes  of  occurrence  of  asphalt  or 
bitumen  have  been  described  by  Malof  and  Greene,^  and  the 
following  table  is  made  up  from  their  works  : 

State.  Localities. 

(viscous     .  .  Pitch  springs  in  Alabama,  France, 
Venezuela, 

solid         .  .  Dead  Sea,  Cuba,  Texas,  Utah. 

2.  Mixed  with  earthy  matter  .  Pitch  Lake,  Trinidad. 

3.  Mixed  with  sand  .         .  .  California,  France,  Utah. 

(bituminous  sandstone) 

4.  Impregnating  limestone  ,  Colorado,  Cuba,  France,  Mexico, 

(bituminous  limestone)  Sicily,  Spain,  Switzerland. 

The  nearly  pure  asphalt  does  not  occur  in  sufficiently  large 
quantities  to  be  worked  on  a  commercial  scale,  and  the  Pitch 
Lake  of  Trinidad.§  long  known  as  a  natural  wonder,  has  not 
been  utilised  to  any  great  extent  until  of  late  years.  The  lake 
occupies  an  area  of  99  acres,  and  is  on  an  average  from  20  to  30 
feet  deep.  Its  surface  is  not  one  continuous  sheet,  but  is  broken 
up  by  pools  and  channels  of  rain  water ;  the  asphalt  is  nearly 
everywhere  solid  enough  to  walk  on.  The  crude  asphalt  has  the 
following  composition  :|| 

Per  cent. 

Bitumen       .......     34 

Water 30 

Clay 36 


100 


"The  bituminous  sandstone  of  California  is  found  in  large 
quantities  at  various  points  between  San  Francisco  -and  Los 
Angeles.  It  contains  about  1  2  to  18  per  cent,  of  bitumen,  and 
the  rest  is  quartz  sand,  in  grains  about  one-tenth  of  an  inch  in 


We  now  come  to  the  bituminous  limestone.  Val-de-Travers, 
in  Switzerland,  and  Seyssel,  in  France,  are  the  most  important 
sources  of  this  rock  for  paving  purposes.  At  Seyssel  there  are 
no  less  than  seven  beds  of  bituminous  limestone,  varying  from  10  to 
20  feet  (3  to  6  m.)  in  thickness.  One  analysis  of  the  rock**  was  as 
follows  : 

*  Boyd,  op.  cit.  p.  586, 

t  Leon  Malo,  L'  Asphalts,     Paris,  1888,  p.  20, 

£  F.  V.  Greene,  "  Asphalt  and  its  Uses,"  Tram.  Am.  List.  M.E.,  vol.  xvii. 
1888,  p.  355. 

§  Wall,  Report  on  the  Geology  of  Trinidad.     London,  1860,  pp.  94,  140. 

!l  Malo,  op.  cit.,  p.  75.  1T  Greene,  op.  cit. 

**  Notice  sur  la  Societe  civile  de  bitume  et  d'asphalte  du  Centre.  Paris,  1889, 
p.  7. 


MODE  OF  OCCURRENCE  OF  MINERALS.          23 

Per  cent. 

Bitumen 670 

Clay         ...  .  3'oo 


Peroxide  of  iron 
Lime 


Magnesia 

Sulphuric  acid 

Phosphoric  acid 

Carbonic  acid,  water  and  loss 


2-60 
45-00 
S'SO 

O'2O 

0'20 

38-60 

99-60 


Barytes. — This  mineral  frequently  accompanies  lead  ore,  but 
veins  are  sometimes  worked  for  it  alone,  as  at  Wotherton  in 
Shropshire. 

Borax. — The  American  borax  deposits*  now  being  worked  are 
situated  in  a  vast  depression  known  as  the  Great  Basin,  which 
exists  between  the  Sierra  Nevada  on  the  West  and  the  Rocky 
Mountains  on  the  East.  Much  of  the  region  is  a  desert  with 
rivers  and  lakes  which  have  no  visible  communication  with  the 
ocean.  The  rivers  lessen  in  volume  gradually  from  absorption 
and  evaporation,  and  end  in  lakes.  During  the  rainy  season  soda  is 
dissolved  out  of  felspars  contained  in  the  lava  which  covers  much 
of  the  country,  and  in  the  dry  season  the  salts  of  soda  crystallise 
out  at  the  surface  in  the  form  of  efflorescent  crusts,  12  to  18 
inches  in  thickness.  The  rain  dissolves  tho  crust,  which  is  carried 
away  in  solution  into  the  rivers,  and  eventually  into  depressions 
which  form  saline  lakes. 

The  two  principal  deposits,  known  as  Borax  Lake  and  Teel's 
Marsh,  were  discovered  in  1873 ;  the  former  lies  in  the  Mojave 
desert  in  California,  450  miles  S.E.  of  San  Francisco,  and  the 
latter  is  in  Nevada.  The  Borax  Lake  is  oval  in  shape,  its 
greatest  length  and  greatest  breadth  being  1 2  miles  and  8  miles 
respectively  (Fig.  1 7).  The  greater  part  of  the  lake  is  covered 
with  a  hard  crust  from  a  few  inches  to  several  feet  in  thickness, 
consisting  of  various  salts.  On  the  top  of  this  crust  there  is 
usually  white  efflorescent  matter  mixed  with  sand,  whilst  under  it 
is  black  mud  containing  much  iron  sulphide,  saline  matter,  and 
sulphuretted  hydrogen. 

The  lake  may  be  divided  into  three  sections,  containing  respec- 
tively: (i)  borax,  (2)  bicarbonate  of  soda,  (3)  common  salt. 
Near  the  centre  of  the  borax  section,  an  area  of  about  300  acres 
is  covered  with  water,  i  inch  to  i  foot  deep,  and  the  mud  under- 
neath is  full  of  large  crystals  consisting  of  carbonate  of  soda  and 
common  salt,  with  a  large  proportion  of  borax.  The  ground 
around  this  "  crystal  bed  "  is  a  dry  hard  crust  containing  car- 
bonate and  sulphate  of  soda  and  i  per  cent,  of  borax.  Upon  this 
hard  crust  there  is  efflorescent  matter  containing  on  an  average  : 

*  C.  Napier  Hake,  "  An  Account  of  a  Borax  Lake  in  California,"  Journ. 
Soc.  Chem.  2nd.,  vol.  viii.  (1889),  p.  854. 


24 


ORE  AND  STONE-MINING. 


Sand     , 

Sulphate  of  soda 
Common  salt 
Carbonate  of  soda 
Borax  . 


Per  cent. 
•      50 
.     16 

,       12 

.       10 

12 


This  surface   efflorescence,  which   is   about   an    inch   thick,  is 
scraped  off  with  shovels  and  swept  into  windrows,  leaving  space 

FIG.  17. 


Borax  Deposit 

Bi-carbonate  of  Soda mmm 

Chloride  of  Sodium  **      l\\\\\\VM 


enough  between  them  for  a  cart  to  pass.  When  the  surface  has 
been  cleared,  the  moisture  finds  its  way  up  again  by  capillary 
action  and  is  evaporated  by  the  sun.  The  formation  of  the 


MODE  OF  OCCURRENCE  OF  MINERALS.          25 

efflorescence  is  allowed  to  go  on  for  three  or  four  years,  and  then 
the  new  crop  is  scraped  off.  The  sand  is  blown  on  by  high 
periodical  westerly  winds. 

The  question  naturally  arises  :  Why  is  the  borax  mainly  con- 
fined to  one  part  of  the  lake  ?  It  appears  necessary  in  order 
to  produce  the  efflorescence  that  the  crust  should  touch  the 
water,  so  as  to  get  a  supply  of  the  saline  matter.  The  borax 
section  is  the  lowest  part  of  the  lake,  and  the  hard  crust  dips  into 
the  water.  When  the  level  of  the  water  is  low  during  a  very  dry 
season,  the  formation  of  the  efflorescence  goes  on  slowly  or  ceases 
altogether.  In  addition  to  borax  there  are  sundry  deposits  of 
borate  of  lime  in  the  same  region. 

Boric  Acid. — Boric  acid  is  obtained  in  considerable  quantities 
from  gaseous  emanations  which  come  to  the  surface  through  in- 
numerable fissures,  probably  dislocations,  in  the  Eocene  and 
Cretaceous  rocks  of  Central  Italy.*  The  best  known  localities 
are  the  four  contiguous  parishes  of  Pomarance,  Castelnuovo  di 
Val  di  Cecina,  Massa  Marittima,  and  Montieri,  in  the  province  of 
Pisa.  A  pit  is  dug  around  any  natural  "  steam-puff,"  or  "  blower  " 
(soffione),  water  is  run  in,  and  the  steam  and  other  gases,  which 
boil  up  through  it,  leave  a  little  boric  acid  in  solution.  The 
gases  that  escape  are  steam,  a  good  deal  of  carbonic  acid  and 
nitrogen,  some  oxygen,  and  a  little  sulphuretted  hydrogen.  The 
very  weak  boracic  solution  is  concentrated  by  heat  derived  from 
some  of  the  steam -puffs.  The  total  production  of  the  provinces 
of  Pisa  and  Grosseto  in  1891  was  1775  metric  tons  of  boric 
acid,  worth  ^£35,500,  and  2056  tons  of  borax  worth  ^5 3, 45 6. 

Carbonic  Acid. — Liquefied  carbonic  acid  is  now  a  regular 
article  of  commerce,  and  Germany  has  taken  the  lead  in  utilising 
the  natural  supplies  of  the  gas.  In  1883  a  bore-hole  was  put 
down  for  carbonic  acid  at  Burgbrohl,f  near  Andernach  on  the 
Rhine,  and  since  then  others  have  been  made  at  Obermendig, 
Tonnistein,  Honningen,  and  Gerolstein.  All  have  been  successful ; 
they  show  that  the  subterranean  supplies  of  carbonic  acid  are  very 
plentiful,  and  that  in  places  where  the  gas  is  already  known  to 
issue,  nothing  but  a  comparatively  shallow  hole  is  needed  to 
increase  the  quantity  very  considerably. 

At  Honningen,  about  five-eighths  of  a  mile  (i  kilometre)  from 
the  Rhine,  an  emanation  of  carbonic  acid  gas  had  long  been 
known,  and  was  piped  off  to  compression  works  before  any  boring 
had  been  made.  The  rocks  in  which  the  carbonic  acid  occurs 
at  Honningen  consist  of  grey  wacke  and  clay-slate,  with  vein-like 
masses  of  quartz  ;  they  belong  to  the  Lower  Devonian  or  so-called 

*  Jervis,  Guida  alle  Acque  Miner ali  cT Italia,  Turin,  1868,  p.  121 ;  and 
1  Tesori  sotterranei  dell'  Italia,  Turin,  1874,  p.  427. 

t  Heusler,  Sitzungsberichte  der  niederrheinischen  GeseUschaft  filr  Natur-  vnd 
Heilkunde  in  Bonn.  Meeting  .of  July  9,  1888. 


26  ORE  AND  STONE-MINING. 

Coblentz  beds,  and  the  bore-holes  at  Burgbrohl,  Obermendig,  and 
Tonnistein  have  been  put  down  in  strata  of  the  same  age. 

The  Honningen  hole  was  bored  with  a  diameter  of  13  inches 
(33  cm.)  to  a  depth  of  230  feet  (70  m.)  from  the  surface.  The 
first  water  containing  carbonic  acid  was  met  with  at  a  depth  of 
92  feet  (28  m.),  and  it  still  remains  at  this  level.  The  quantity 
of  gas  is  greater  than  was  given  off  by  the  old  emanation  at 
the  surface,  and  is  reckoned  to  be  500  litres  (nearly  18  cubic  feet) 
per  minute,  corresponding  to  720  cubic  metres  (25,428  cubic  feet) 
of  gas,  or  i  kilog.  (2*2  Ibs.)  of  liquid  carbonic  acid  in  twenty-four 
hours. 

The  Honningen  spring  differs  from  some  others  by  the  fact  that 
at  a  depth  of  230  feet  (70  m.)  the  water  is  already  at  a  tempera- 
ture of  72°  F.  (22°  C.),  and  probably  a  higher  temperature  would 
be  reached  if  the  hole  were  deepened.  A  second  hole  has  been 
bored  to  a  like  depth  by  another  company  at  a  distance  of  50  feet 
(15  m.)  from  the  first,  and  a  good  supply  of  gas  has  been 
obtained. 

At  Gerolstein  the  bore-hole  passed  through  alluvial  gravel  into 
solid  dolomite,  and  was  stopped  at  a  depth  of  156  feet  (47 J  m.). 
It  seems  probable  that  the  hole  has  penetrated  into  a  wide  fissure 
filled  with  loose  fragments  of  dolomite.  The  water  which  flows 
out  contains  such  an  excess  of  carbonic  acid  that  it  froths  up  at 
the  surface.  The  quantity  of  water  coming  up  is  8476  cubic  feet 
(240  cb.  m.)  in  twenty- four  hours,  with  an  estimated  minimum  of 
1060  cubic  feet  (30  cb.  m.)  of  carbonic  acid  gas  per  hour. 

Though  natural  outflows  of  this  gas  are  common,  especially  in 
volcanic  regions,  the  number  of  places  where  they  are  utilised 
commercially  is  small.  In  addition  to  the  German  localities,  I 
may  mention  two  places  in  Italy.*  There  are  springs  of  water 
impregnated  with  carbonic  acid  and  emanations  of  the  gas  at 
Cinciano,  in  the  Yalle  d'Elsa,  province  of  Siena,  which  are  used 
for  making  pure  bicarbonates  of  potash  and  soda  from  the  crude 
carbonates,  and  also  for  making  white-lead  from  the  acetate, 
the  gas  being  perfectly  free  from  any  sulphuretted  hydrogen. 
Similar  blowers  (soffioni)  at  Montione,  near  Arezzo,  are  em- 
ployed for  the  latter  purpose. 

Clay  (including  common  clays,  china-clay,  fire-clay,  fuller's 
earth,  pipe-clay,  potter's  clay). 

As  a  rule,  clay  occurs  in  the  form  of  stratified  deposits,  and  this 
is  the  case  with  an  important  British  clay,  the  fire-clay  of  the  Coal 
Measures,  which  is  found  in  beds  sometimes  several  feet  in  thick- 
ness and  usually  under  a  seam  of  coal.  The  coal  is  often  too  thin 
to  be  worked  and  may  be  only  i  inch  thick,  but  both  coal  and  the 
underlying  fire-clay  may  be  worth  working  together.  Various 
beds  of  clay  of  Secondary  and  Tertiary  age  are  dug  in  England 

*  Jervis,  Guida  alle  Acque  Minerali  d1  Italia.    Turin,  1868,  pp.  54,  63. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


27 


for  making  pottery,  drain  pipes,  and  Portland  cement.  The  beds 
of  fuller's  earth  near  Bath  are  of  Oolitic  age,  whilst  those  which 
are  mined  in  Surrey  belong  to  the  Lower  Greensand. 

The  china  clay*  of  Cornwall  and  Devon  exists  in  irregular 
deposits  of  a  totally  different  nature  ;  they  consist  of  granite 
decomposed  in  situ,  not  by  atmospheric  agencies  as  is  often 
stated,  but  far  more  probably  *by  hydrofluoric  acid  brought  up 
by  deep-seated  fissures.  That  the  decomposition  was  due  to  the 
veins  or  fissures  seems  evident  from  the  fact  that  the  altered  rock 
occurs  in  bands  adjacent  and  parallel  to  them.  Where  the 
veins  are  numerous  a  very  large  mass  of  china  clay  may  be  found, 
extending  for  a  width  of  a  hundred  or  more  yards,  and  a  length 
of  a  quarter  of  a  mile  or  half  a  mile  along  their  strike ;  the  depth 
to  which  the  alteration  of  the  granite  continues  is  quite  unknown. 
The  veins  are  often  tin-bearing,  and  workings  for  tin  have  led  to 
the  discovery  of  china  clay;  indeed  the  two  minerals  may  be 
worked  together.  The  altered  granite  consists  of  quartz,  white 
mica,  sometimes  a  little  gilbertite,  and  felspar  which  has  been 
more  or  less  completely  converted  into  kaolin.  This  last  mineral 
is  easily  separated  when  the  soft  rock  is  washed  down  by  a 
current  of  water,  for  it  is  so  finely  divided  that  it  is  the  last  to 
settle  when  the  milky  stream  is  led  into  depositing  pits. 

Cobalt. — The  cobalt  ore  worked  at  Skutterud  in  Norway  is 
found  in  certain  bands  of  quartz 
schist  and  mica  schist  which 
contain  small  particles  of  cobalt 
glance,  skutterudite,  cobalti- 
ferous mispickel,  ordinary  mis- 
pickel,  iron  pyrites,  and  other 
metallic  sulphides. 

The  accompanying  figure  (18) 
illustrates  what  I  saw  at  Skut- 
terud some  years  ago ;  a,  a,  a, 
are  bands  of  mica  schist  with 
little  or  no  cobalt  ore ;  b,  b,  are 
bands  of  quartz  schist  containing 
the  cobaltic  minerals  dissemi- 
nated through  them,  and  c,  a  cobaltiferous  band  of  mixed  quartz 
schist  and  mica  schist. 

The  rocks  appear  to  be  altered  sedimentary  strata,  and  the 
deposits  must  be  spoken  of  as  beds.  The  strike  is  N.  and  S.,  and 
the  beds  dip  at  a  very  high  angle  to  the  east.  Quartz  schist  is 
the  rock  most  likely  to  be  cobaltiferous,  the  mica  schist  may  be 
also  worth  working,  but  hornblende  schist  is  poor.  The  cobaltic 
beds  are  commonly  two  or  three  fathoms  wide,  but  a  number  of 

*  J.  H.  Collins,  The  Hensbarrow  Granite  District.  Truro,  1878.  And*, 
"  On  the  Nature  and  Origin  of  Clays  :  the  Composition  of  Kaolinite," 
JUin.  Mag.  London,  vol.  vii.  (1887),  p.  205. 


as 


28 


ORE  AND  STONE-MINING. 


adjacent  beds  may  produce  a  much  greater  thickness  of  cobalt- 
iferous  rock. 

In  New  Caledonia*  the  mode  of  occurrence  is  totally  different. 


FIG.  19. 
a  a  irs-w-Ki  fain  of  Chromic  Iron 

of  fragm  en  U  of  Chromic  Iron 
ited  from  Uit  Veins 
of  ColcUl  it 'trout  Afanyontse  ore 


The  cobalt  is  found  as  a  hydrated  oxide,  without  a  trace  of 
sulphur  or  arsenic,  intimately  associated  with  hydrated  oxide  of 
manganese,  in  irregular  "  pockets  "  of  red  clay  in  serpentine.  In 
Fig.  1 9  S  is  the  serpentine  and  A  the  red  clay ;  a  a  represent 
veins  of  chromic  iron  in  the  serpentine ;  a'  a'  is  a  little  stratum 
of  fragments  of  chromic  iron  derived  from  these  veins,  whilst  b  b 
are  beds  of  cobaltiferous  manganese  ore  in  the  clay.  The  ore 
lying  about  on  the  surface  or  obtained  from  these  pockets  has  from 
2  J  to  3  per  cent,  of  cobalt. 
At  Rhyl,  in  Flintshire,t  there  is  a  curious  irregular  cavity  in 

FIG.  20. 


HORIZONTAL  SCALE 

MOO          0          1000       2000      3000       4000       5000      6000       7000       8000       SpOQ      IQOttOnv 

VERTICAL  SCALE  THREE  TIMES  THAT  OF  THE  HORIZONTAL  SCALE 

the  Mountain  Limestone  filled  up  with  red  clay  which  encloses 
small  lumps  of  asbolane.  This  deposit  was  worked  on  a  small 
scale  for  several  years. 

Copper. — The    most    important  copper  mines  of    the   world 

*  Levat,  "  Memoire  sur  les  progr^s  de  la  metallurgie  du  nickel."    Ann. 
Mines,  ge  serie,  vol.  i.  p.  147. 

f  Irans.  R.  Cornwall  Geol.  Soc.,  vol.  x.  p.  107. 


MODE  OF  OCCURRENCE  OF  MINERALS.         29 

nowadays  are  those  of  Mansfeld  in  Germany,  Rio  Tinto  and 
Tharsis  in  Spain,  San  Domingos  in  Portugal,  Lake  Superior, 
Arizona  and  Montana  in  the  United  States. 

Germany. — Copper  mining  has  been  carried  on  near  Mansfeld,  in 
the  Prussian  province  of  Saxony,  since  the  commencement  of  the 
twelfth  century,  and  the  district  is  specially  interesting  from  the 
fact  that  the  ore  is  found  in  a  bed  or  seam,  which  can  be  worked  with 
profit  in  spite  of  its  thinness  and  comparative  poverty  in  metal. 

The  Mansfeld  district  (Figs.  20  and  21)  is  mainly  occupied  by 
the  rocks  of  the  following  formations  : — 

Trias   .         .  ,  .         .        3.  Bunter  Sandstone. 

-p  (2.  Zechstein. 

Permian       .         .         .         .   \         -^  ,,  •,.         , 

I    i.  Rothliegendes. 

(1)  "Das  Rothliegende,"  or  the  red  floor,  is   the  old  miners' 
name  for  the  sandstone  and   breccias  lying  almost  immediately 
below  the  bed  of  cupriferous  shale.     In  contradistinction  to  the 
ore-bed,  it  is  also  called  "  das  Todtliegende  "  (the  dead  floor).     It 
can  always  be  distinguished  by  its  characteristic  red  colour.     One 
of    its   most    constant    beds   is    the    so-called    "  porphyry    con- 
glomerate," consisting   of    pebbles   of    milk-white   quartz,    hard 
siliceous  slate,  and  grey  and  reddish  porphyry, 

(2)  The  Zechstein  formation  consists  of  three  divisions.     The 
lowest  division  comprises  the  "  Weissliegendes,"  the  bed  of  copper 
shale  and  the  Zechstein.     The  middle  division  consists  of  the 
anhydrite  or  older  gypsum,  or  of  its  equivalent  the  "  Rauchwacke," 
"  Asche,"  "  Rauhstein  "  and  Stinkstone ;    the  upper  division  is 
made  up  of  variegated  clays  with  intercalations  of  gypsum,  the 
residues  left  when  some  of  it  is  dissolved  away  (Asche),  and  cal- 
careous or  dolomitic  concretions.* 

The  "  Weissliegendes  "  is  petrographically  like  the  "  Rothlie- 
gendes" below  it,  and  is  looked  upon  by  many  as  merely  an 
uppermost  bed  deprived  of  colour.  Above  it  with  great 
regularity  comes  the  ore  bed,  a  blackish,  bituminous,  marly  shale, 
about  15  to  1 8  inches  thick. 

The  ore  of  the  shale  bed  is  usually  disseminated  through  it  in 
the  form  of  fine  particles  (/Speise),  which  impart  a  metallic  glitter 
to  the  surface  of  cross-fractures.  A  golden  yellow  col  our  indicates 
chalcopyrite,  a  bluish  and  reddish  variegated  look,  bornite,  and  a 
steel  grey,  seen  more  rarely,  is  due  to  copper  glance ;  whilst  a 
greyish  yellow  denotes  a  predominance  of  iron  pyrites,  and  a 
leaden  grey,  galena.  The  following  minerals  also  occur :  cinnabar, 
blende,  kupfernickel,  speiskobalt,  and  compounds  of  manganese, 
molybdenum  and  selenium.  Oxidised  ores  are  found  at  the  outcrop. 

*  The  figures  and  some  of  the  details  concerning  the  Mansfeld  mines  are 
borrowed  from  a  pamphlet  entitled.  "  Der  Kupferschieferbergbau  und  der 
Hiittenbetrieb  zur  Verarbeitung  der  gewonnenen  Minern  in  den  beiden 
Mansf  elder  Kreisen  der  Preussischen  Provinz  Sachsen."  Eisleben,  1889. 


ORE  AND  STONE-MINING. 


and  are  naturally  of  secondary  origin.  In  addition  to  the  finely 
disseminated  grains,  there  are  often  small  strings  of  bornite  and 
copper  glance,  generally  parallel  to  the  bedding,  and  thin  coatings 
of  copper  glance,  bornite,  chalcopyrite,  and  native  silver  along  the 


FIG.  21. 
SECTION  OP  EDUARD  II.  SHAFT. 


Soil 


Bunter  Sandstone 


Gypsum    . 

Stinks  tone  and  "  Asche ' 

Blue  Shale 

Stinkstone  and  "  Asche ' 


Gypsum    . 


Zechstein  . 
Copper  Shale 
R  othliegendes 

Conglomerate 


Rothliegendes 


Rothliegendes  'with  Melaphyre 


Rothliegendes  . 


M  § 


planes  of  bedding  or  in  cross  joints.  Finally  there  may  be  small 
nodules  of  copper  ore  lying  singly. 

The  whole  of  the  bed  of  copper  shale  is  ore-bearing ;  but,  as  a 
rule,  only  the  bottom  3  or  4  inches  are  rich  enough  to  be  worked 
with  profit.  Occasionally  6  or  7  inches  can  be  taken,  and  in  ex- 
ceptional cases  the  whole  of  the  bed  goes  to  the  smelting  works. 

Although  there  are  minor  variations,  the  shale  is  fairly  regular 


MODE  OF  OCCURRENCE  OF  MINERALS. 


31 


as  regards  ore-bearing  when  dealt  with  on  a  large  scale.  On  an 
average,  in  the  true  Mansfeld  district,  between  Gerbstedt  and 
Eisleben,  it  contains  2  to  3  per  cent,  of  copper  and  163  oz.  of 
silver  to  the  ton  of  copper  (5  kil.  per  metric  ton). 

The  importance  of  the  copper  shale  will  be  appreciated  from 
the  fact  that  in  the  year  1888,  14,178  persons  were  employed  at 
the  mines,  or  more  than  all  the  miners  of  Cornwall  and  Devon. 
The  output  of  ore  was  469,716  metric  tons,  which  produced 
13,600  metric  tons  of  refined  copper,  and  77,950  kilogrammes 
(208,845  Troy  pounds)  of  silver. 

Spain    and  Portugal. — The    famous    mines     of    Rio  Tinto,* 

FIG.  22. 


Tharsis,  and  San  Domingos  are  contained  in  a  great  metalliferous 
belt  of  country,  140  miles  long  by  30  miles  wide,  stretching 
across  the  province  of  Huelva  in  Spain  and  into  Portugal.  The 
rocks  consist  of  slate  of  Upper  Devonian  age,  often  altered 
locally  into  jasper,  talc  schist,  chiastolite  schist,  etc.,  with  great 
intrusions  of  quartz  and  felspar-porphyries,  diabase,  quartz- 
syenite,  and  granite.  The  geological  horizon  of  the  slate  has  been 
determined  by  finding  Posidonomya  Becheri,  P.  acuticosta,  a 
goniatite  allied  to  G.  subsulcatus  and  other  fossils.  The  strike  of 
the  slates  is  about  15°  to  25°  north  of  west,  and  the  dip  either 

*  Collins,  "  On  the  Geology  of  the  Rio  Tinto  Mines,  with  some  General 
Kemarks  on  the  Pyritic  Kegion  of  the  Sierra  Morena,"  Quart.  Journ.  Geol. 
&>c.,  vol.  xli.  (1885),  p.  245. 


ORE  AND  STONE-MINING. 


vertical  or  at  a  high  angle  to  the  north.  Through  having  the  same 
general  strike  as  the  slate,  the  masses  of  porphyry  may  appear  to 
be  interstratified,  but  a  close  examination  of  the  junction  proves 
them  to  be  intrusive. 

As  shown    by  the   map   (Fig.    22),   there  are  four  principal 

deposits  of  pyrites  at  Eio 

'IG'23-  Tinto,   viz.,    the     North 

Lode,  the  South  Lode, 
the  San  Dionisio  Lode, 
and  the  Valley  Lode. 
They  all  occur  at  or 
near  the  junction  of  the 
porphyry  and  the  slate  ; 
and  they  are  supposed  by 
Mr.  Collins  to  occupy 
cavities  produced  by  fis- 
sures. On  the  other  hand, 
the  somewhat  similar 
deposit  of  the  Rammels- 
berg  mine  in  the  Hartz 
is  now  unanimously  con- 
sidered by  geologists  to 
be  of  sedimentary  origin, 
and  to  be  strictly  con- 
formable to  the  surround- 
ing beds  of  slate. 

The  South  Lode,  the 
one  most  largely  wrought 
hitherto,  is  sometimes  as 
much  as  450  feet  (140  m.) 
wide,  and  is  known  along 
the  strike  for  a  -distance 
of  about  a  mile,  or,  in- 
deed, for  two  miles  if  the 
San  Dionisio  lode  is  con- 
sidered to  be  an  extension 
of  it  to  the  west.  Fig. 
23  is  a  cross-section  of 
the  South  Lode  at  San 
Inocente  shaft,  and  Figs.  24,  25,  and  26  are  taken  at  points  a 
little  to  the  east. 


INDEX  FOR  FIGS.  23  TO  26. 


Porphyry. 


Porphyry  worked 
away. 


Slate  worked 
away. 


Pyrites. 


Pyrites  -worked 
away. 


\  Ferruginous  breccia  and gozzan. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


33 


Figures*  27  and  28  show  the  curious  manner  in  which  the  San 
Dionisio  lode  swells  out  suddenly  at  a  depth  of  about  150  metres 
from  the  surface,  and  actually  attains  the  enormous  width  of  200 
metres.  A,  is  slate  ;  B,  porphyry ;  C,  cupreous  pyrites ;  D,  iron 
ore,  the  "  gozzan  "  or  iron  cap  of  the  lode.  The  slate  is  dipping 
steeply  towards  the  lode,  as  indicated  by  the  lines  denoting  planes 
of  bedding.  The  hatching  of  C  itself  does  not  represent  any 
structure.  It  will  be  interesting  geologically  and  important 
commercially  to  watch  the  further  development  of  the  workings 
upon  this  remarkable  lode. 

The  character  of  the  ore  varies  a  good  deal.  Mr.  Collins 
names  fourteen  different  kinds.  The  principal  are  :  (i)  Ore 
treated  for  copper  on  the  spot,  and  (2)  that  which  is  exported. 
The  former  consists  of  fine-grained  and  compact  iron  pyrites 
with  i  to  2\  per  cent,  of  copper,  existing  as  copper-pyrites 
minutely  disseminated  throughout  the  mass,  and  the  latter  only 
differs  by  being  richer  in  copper,  and  containing  up  to  3!  per 
cent. 

Little  veins  of  copper-pyrites,  erubescite,  and  occasionally 
copper-glance,  more  or  less 

mixed    with     iron  -  pyrites,  FIG.  27. 

quartz,  blende,  and  other 
minerals,  traverse  the  mass, 
and  there  is  sometimes  a 
compact  mixture  of  galena, 
blende,  chalcopyrite,  and 
iron-pyrites  resembling  the 
"  bluestone  "  of  Anglesey. 

Few  mines  in  the  world 
are    of     more     importance 
than  Rio  Tinto.     The  quan- 
tity   of    ore    extracted     in  I  9  *  * 
i892f  was  1,402,063  tons  of     ^mmm- 
21  cwt.,  of   which  995,151                         ^         ^ 
tons  were    for   local    treat- 
ment   and   406,912    for    shipment  to  Great  Britain,   Germany, 
and  the  United  States.     The  average  percentage  of  copper  was 
2-819. 

The  deposits  of  iron  ore  marked  on  the  map  are  horizontal 
beds,  probably  formed  at  the  bottom  of  lakes  in  Miocene  times. 
The  ore  is  brown  haematite,  with  varying  proportions  of  silica. 
The  sections  show  that  the  upper  part  of  the  pyrites  has  been 
converted  into  a  gozzan  ;  much  of  this  is  a  good  iron  ore,  and  is 
being  stocked  for  disposal  at  some  future  time. 

*  From  drawings  kindly  supplied  by  Mr.  James  Osborne,  the  general 
manager  of  the  Rio  Tinto  Mines. 

f  Rio  Tinto  Co.  Ltd.,  Twentieth  Annual  Report,  April  1893. 

C 


34 


ORE  AND  STONE-MINING. 


The  Tharsis  and  San  Domingos  mines  are  likewise  vast  under- 
takings, and  the  total  imports  of  cupreous  iron-pyrites  into  this 
country  alone  from  Spain  and  Portugal  in  1891  amounted  to 
608,000  tons,  worth  over  one  million  sterling.* 


FIG.  28. 


SCALE 


United  States. — Crossing  the  Atlantic,  we  will  now  turn  our 
attention  to  the  mines  on  the  southern  shore  of  Lake  Superior, 
which  are  remarkable  for  their  productiveness,  and  which  are 
equally  attractive  to  the  geologist  and  to  the  miner. 

The  copper-bearing  districtf  lies  on  a  long  peninsula,  15  to  20 
miles  wide,  with  a  north-easterly  trend,  which  projects  into  Lake 
Superior  (Fig.  29  J:)  some  60  miles  beyond  the  general  run  of 
its  southern  shore,  and  terminates  in  Keweenaw  Point.  The 
western  half  of  the  peninsula  is  formed  by  rocks  belonging  to  the 
Keweenaw  Series,  considered  by  many  to  be  younger  than  the 
Huronian  and  older  than  the  Cambrian.  They  consist  of  sand- 
stones and  conglomerates,  interstratified  with  flows  of  eruptive 
rocks  of  various  kinds. 

The  beds  dip  to  the  north-west,  at  an  angle  of  22°  in  the 
northern  part  of  the  mineral  district,  and  in  going  south  the 
dip  increases  to  56°.  The  outcrop  of  the  actual  copper-bearing 
part  of  the  series  occupies  a  belt  of  country  from  4  to  5  miles 
wide. 


*  Mm.  Stat.for  i8gi.    London,  1892,  p.  59. 

f  B.  D.  Irving,  "  The  Copper-bearing  Eocks  of  Lake  Superior,"  United 
States  Geol.  Survey.  Washington,  1883.  Douglas,  "  The  Copper  Resources 
of  the  United  States,"  Trans.  Amer.  Inst.  M.E.,  vol.  xix.  1890,  p.  679 ; 
and  Jour.  JSoc.  Arts,  vol.  xli.  1892,  p.  39. 

J  Engineering,  vol.  1.  1890,  p.  553;  and  Guide-book  prepared  for  the 
members  of  the  Iron  and,  Steel  Institute,  1890. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


35 


The  modes  of  occurrence  of  the  copper  may  be  classified  as 
follows : 

A    BEDS  I  T  *  ^°PPer~bearing  conglomerate  and  sandstone. 

I  2- 


B.  VEINS. 


Copper-bearing  amygdaloid. 


A.  (i)  The  deposits  of  the  first  class  are  beds  of  conglomerate 
and  sandstone  impregnated  with  native  copper.  In  most  cases 
the  cupriferous  beds  are  interstratified  with  diabase  flows ;  but 

FIG.  29. 


this  connection  between  the  proximity  of  diabase  and  the  presence 
of  copper  is  not  universal.  The  copper  occurs  as  the  cementing 
material  of  the  pebbles  and  grains  of  sand,  and  also  replaces  the 
pebbles  themselves,  large  stones  several  inches  or  even  a  foot  in 
diameter  being  converted  into  the  native  metal.  The  copper  has 
evidently  been  deposited  from  aqueous  solutions.  By  far  the 
greatest  proportion  of  the  Lake  Superior  copper  is  obtained  from 
these  conglomerates. 

A.  (2)  The  cupriferous  amygdaloids  are  portions  of  the  old  lava 
flows,  and  are  not  strictly  speaking  beds  as  defined,  though  it  is 
•convenient  to  call  them  by  that  name. 

Often  they  are  highly  altered  and  have  lost  all  sign  of  having 


36  ORE  AND  STONE-MINING. 

once  been  vesicular ;  the  native  copper  which  they  contain  must 
have  found  its  way  in  long  after  their  eruption.*  It  is  usually 
very  irregularly  distributed,  and  the  parts  rich  enough  to  be 
worked  may  be  surrounded  by  much  poor  or  barren  rock.  The 
presence  of  epidote  and  calcite  is  regarded  as  a  good  indication 
for  the  proximity  of  copper. 

B.  As  the  cupriferous  lava  beds  and  conglomerates  are  locally 
called  "veins,"  it  is  necessary  to  say  that  the  real  veins  run  in 
a  direction  at  right  angles  to  the  general  trend  of  the  beds,  and 
are  almost  vertical.  Their  usual  width  is  from  one  to  three 
feet,  but  it  may  become  as  much  as  10,  20,  and  even  30  feet. 
They  are  largest  and  richest  when  they  have  amygdaloid  or  loose- 
textured  diabase  for  their  walls,  and  they  become  pinched  up  and 
worthless  in  the  compact  greenstone  or  sandstone.  To  a  great 
extent  they  consist  of  altered  rock,  and  are  an  instance  of  lodes 
formed  by  replacement  of  the  "  country."  According  to  Irving 
these  veins  were  formed  by  copper-bearing  solutions  which  found 
a  path  through  zones  of  fissured  rock,  instead  of  following  certain 
easily  permeable  beds.  The  copper  is  in  the  native  state,  and 
generally  in  masses -of  considerable  size,  the  largest  found  weigh- 
ing nearly  600  tons. 

The  following  statistics  relating  to  the  Lake  Superior  mines 
are  taken  from  a  guide-book  prepared  for  the  members  of  the 
Iron  and  Steel  Institute  in  1890. 


Name  of  Mine. 

Nature  of 
deposit. 

Depth 
in  feet. 

Tons  rock 
hoisted 
1889. 

Tons 
Refined 
Copper 

1889. 

Tons 
Copper 
to  date. 

Per  cent, 
copper 
in  rock 
stamped. 

Dividends 
to  date. 

Dollars. 

Alloucz   .     . 

Conglo- 

1700 

126,125 

881 

11,427 

076 

merate 

Calumet  and 

Hecla    .     . 

I  3750 

807,918 

24-334 

301,538 

3-01 

33,359,000 

Peninsula    . 

600 

— 

368 

Tamarack    . 

2818 

196,707 

5.Si8 

16,624 

3-26 

1,200,000 

Atlantic  .     . 

Amyg-da-  ,   1660 

288,040 

1,849 

23,786 

0-66 

560,000 

loid 

Copper  Falls 

H 

1500 

— 

435 

10,789 

070 

100,000 

Franklin      . 

fj 

2620 

186,740 

2,i73 

3L96i 

1-87 

960,000 

Huron     .     . 

„ 

1800 

159.333 

1,109 

10,652 

0-98 

Kearsage-     . 

5, 

1000 

76,54i 

960 

1,384 

171 

80,000 

Osceola  .     . 

n 

2162 

208,299 

2,631 

25,312 

1-29 

1,222,500 

Quincy    .     . 

„ 

3070 

123,998 

3-203 

53.250 

272 

5,250,000 

Central   .    . 

Veins        2900 

Mostly 

635       20,355 

1,930,000 

mass. 

1 

As  will  be  seen  from  these  figures,  the  Calumet  and  Hecla 
mine  is  the  most  important  on  Lake  Superior.  The  bed  of 
copper-bearing  conglomerate  is  from  8  to  25  feet  thick,  and 


Irving,  Op.  cit.  p.  421. 


MODE  OF  OCCURRENCE  OF  MINERALS.          37 

about  12  feet  on  an  average.  The  dip  is  37^°  to  the  north-west. 
The  depth  of  the  mine  which  is  given  in  the  table  is  measured 
on  the  dip,  and  would  be  about  2,280  feet  if  measured  vertically ; 
but  these  figures  are  now  greatly  exceeded,  and  shafts  are  being 
sunk  which  will  enable  the  Calumet  and  Hecla  and  the  Tamarack 
mines  to  be  worked  to  the  enormous  depth  of  5000  feet. 

The  very  low  percentage  of  copper  in  the  Atlantic  amygdaloid, 
which  nevertheless  is  worked  at  a  profit,  is  remarkable ;  but, 
unlike  the  amygdaloids  generally,  the  Atlantic  rock  is  very 
regular  in  its  yield.  This  makes  up  for  its  poverty. 

Arizona*  produces  large  quantities  of  oxidised  ores  of  copper, 
especially  the  oxide  and  carbonates,  which  occur  in  or  adjacent  to 
the  Carboniferous  limestone.  Sometimes  there  are  irregular  ore- 
bodies  at  the  contact  of  the  limestone  with  granite  or  with  sand- 
stone. Masses  of  sulphuretted  ores  which  have  escaped  decay 
show  whence  the  oxidised  ores  have  been  derived. 

The  Butte  district,  Montana,f  has  surprised  the  world  of 
late  years  by  the  enormous  quantities  of  copper  ore  which 
it  has  sent  into  the  market.  The  deposits  are  east  and  west 
lodes  in  granite,  usually  dipping  steeply  to  the  south.  The 
main  lode,  which  supports  the  celebrated  Anaconda  and  Parrott 
mines,  has  proved  productive  for  a  distance  of  three  miles  along 
the  strike.  The  principal  ores  are  erubescite,  copper  glance, 
and  chalcopyrite.  Everywhere  near  the  lodes  the  granite  is  soft 
and  friable,  and  often  contains  ore-bodies.  Though  the  granite 
has  been  greatly  fissured,  it  seems  likely  that  much  of  the  ore 
does  not  fill  up  cracks,  but  has  gradually  taken  the  place  of  the 
rock  by  a  process  of  substitution.  The  width  of  the  lodes  varies 
considerably ;  however,  on  an  average  it  may  be  taken  at  ten  feet. 
The  copper  ore  is  silver-bearing,  the  proportion  varying  from  J  oz. 
per  unit  of  copper  to  2  oz.  per  unit. 

The  upper  parts  of  the  veins  consisted  of  oxidised  minerals,  from 
which  the  copper  had  been  leached  out  almost  entirely,  but  in  which 
the  silver  was  retained  and  formed  the  original  object  of  the  mining. 
At  the  Anaconda  mine  there  was  no  copper  worth  speaking  of 
for  the  first  400  feet  in  depth;  then  came  a  rich  zone  of 
oxisulphides  and  erubescite,  considered  to  contain  some  of  the 
copper  which  had  been  dissolved  out  of  the  vein  at  a  higher  level, 
and  after  lasting  for  zoo  feet  it  was  succeeded  by  the  unaltered 
sulphides. 

Diamonds. — By  far  the  most  important  diamond  district  in 
the  world  is  Kimberley,  in  Cape  Colony,  648  miles  by  rail  from 
Cape  Town.  Strange  to  say,  most  of  the  precious  gems  are 

*  Douglas,  Op.  cit. 

t  Douglas,  Op.  cit.  Vogelsang,  "  Mittheilungen  iiber  den  Kupferberg- 
bau  in  Nord-America,"  Zeitschr.  B.-  H.-  u.  S.-  Wesen,  vol.  xxxix.  1891, 
p.  231.  G.  vom  Kath,  "  Ueber  das  Gangrevier  von  Butte,  Montana,"  N. 
Jahrb.f.  Miner.  Geol  u.  Paldont.,  vol.  i.  (1885),  p.  158. 


ORE  AND  STONE-MINING. 


obtained  from  four  deposits  situated  in  close  proximity  to  each 
other ;  indeed,  all  four  are  included  in  a  circle  three  miles  in 
diameter.  The  masses  of  diamond- bearing  rock  may  be  described 
as  huge  vertical  columns,  of  round,  oval,  or  kidney-shaped  section, 
as  shown  by  Figs.  30  and  31.*  The  un weathered  diamond-bearing 


FIG.  30. 

_fiOC/f  SHAFT 


FIG.  31. 


D£  BEERS  MINE 


KIMBERLEY 
MINE 


rock,  locally  known  as  "  blue  ground,"  or  "  blue,"  is  a  breccia, 
consisting  of  fragments  of  shale,  basalt,  diorite,  and  a  little 
sandstone,  cemented  together  by  olivine  rock  containing  diamonds 
and  various  other  minerals,  such  as  bronzite,  biotite,  talc, 
garnet,  graphite,  magnetite,  and  iron 
pyrites.  The  surrounding  rocks,  locally 
called  "  reef,"  are  beds  of  carbonaceous 
and  pyritiferous  shale  lying  horizontally, 
and  sheets  of  basalt  and  melaphyre, 
under  which  comes  quartzite.  The  mela- 
phyre is  a  hard  amygdaloidal  rock, 
which  has  also  been  called  olivine  dia- 
base.f  Large  detached  masses  of  the 
surrounding  rocks  are  sometimes  in- 
cluded in  the  "  blue,"  and  are  then 
known  as  "  floating  reef."  The  upper 
parts  of  the  deposits  have  been  decom- 
posed by  atmospheric  agencies,  and  changed  into  a  soft  friable 
earth  to  a  depth  varying  from  45  to  60  feet,  and  the  colour  is 
yellow,  instead  of  the  slaty  blue  of  the  unweathered  rock.  The 
surrounding  rocks  have  naturally  shared  in  this  weathering. 

*  De  Beers  Consolidated  Mines,  Limited,  Second  Annual  Report,  1890, 
including  a  technical  report  with  plates, 
f  Ibid.  p.  13. 


DUTOITSPAM 
BULTFONTeiN^Q 


MODE  OF  OCCURRENCE  OF  MINERALS.  39 

The  diamond-bearing  rock  appears  to  be  the  filling-up  of  the 
necks  or  throats  of  old  volcanoes  by  a  mud  from  below.  From 
the  frequent  occurrence  of  broken  diamonds  it  is  fairly  inferred 
that  the  gems  were  not  formed  in  situ,  but  were  carried  up 
with  the  "  blue." 

Not  only  does  the  yield  in  'diamonds  vary  in  the  different  mines, 
but  the  diamonds  themselves  have  their  peculiar  characteristics, 
which  enable  the  expert  to  say  at  once  from  which  mine  a  stone 
has  been  obtained.  The  average  yield  of  the  "blue  ground" 
per  load  of  16  cubic  feet  *  is  as  follows : — - 

Value  per  carat 
Area.  Carats  per  load.  in  1889. 

Bultfontein      .  .               i  to    £  .  .£177 

De  Beers  .        .  .  .     i£toi$  .         .  .176 

Du  Toil's  Pan  .  .                |  to    |  .                I   19  io£ 

Kimberley        .  .  .     l|  to  1$  .  '      .  .       i     7    9i 

In  addition  to  these  four  mines  there  are  some  other  workings 
in  the  neighbourhood,  such  as  Wesselton  and  St.  Augustine ; 
whilst  at  Jagersfontein,  80  miles  to  the  south  in  the  Orange  Free 
State,  there  is  a  similar  deposit,  producing  stones  of  the  finest 
water. 

The  commercial  importance  of  the  diamond  deposits  cannot  be 
overestimated,  for  the  value  of  the  diamonds  produced  annually 
at  Kimberley  is  between  three  and  four  millions  sterling,  or  more 
than  the  value  of  the  gold  produced  by  any  one  of  the  British 
colonies.f 

Until  lately,  the  largest  diamond  found  weighed  42 8 J  carats 
in  the  rough  state,  and  228^  carats  after  cutting  ;  it  came  from 
De  Beers  mine.  This  large  stone  has  been  eclipsed  by  one  of  96 9 J- 
carats  discovered  at  Jagersfontein  in  the  month  of  June  last. 

In  addition  to  diamonds  found  in  a  solid  matrix,  there  are 
those  from  the  river  diggings.  It  was  in  the  recent  alluvium 
of  the  Yaal  River  that  diamonds  were  first  discovered  in  1867, 
and  though  thrown  into  the  shade  by  the  output  of  the  mines, 
the  gravel  is  still  washed  by  parties  of  men  scattered  along  the 
banks  of  the  river  for  a  distance  of  70  miles. 

Diamonds  are  found  in  alluvial  gravel  and  in  conglomerate  in 
Brazil,  India,  and  other  localities. 

Flint. — It  may  be  thought  strange  by  some  that  I  give  flint  a 

*  Sixteen  cubic  feet  of  broken  ground  correspond  to  about  9  cubic  feet 
of  solid  ground. 

t  Further  information  about  the  Kimberley  diamond  mines  will  be  found 
in  the  following  publications  : — T.  Reunert,  "  Diamond  Mining  at  the 
Cape,"  History,  Production*,  and  Resources  of  the  Cape  of  Good  Hope.  Cape 
Town,  1886.  C.  Le  Neve  Foster,  "Mining  Industries,"  Reports  on  the 
Colonial  and  Indian  Exhibition.  London,  1887.  E.  Boutan,  "Sur  1'etat 
actuel  des  mines  de  diamants  du  Cap,"  Genie  Civil.  Paris,  January  26, 
1889. 


40  ORE  AND  STONE-MINING. 

place   among  the  important  minerals  which  deserve  special  de- 
scription.    My  reasons  for  mentioning  it  are  twofold.     First,  the 


FIG.  32. 


Sand  and  Gravel 


Dead  Lime 


Soft  White  Chalk 

Horns  Flint 

Soft  White  Chalk        . 

Toppings  Flint   . 

Soft  White  Chalk 

First  Pipeclay     . 
Hard  White  Chalk     . 
Upper  Crust  Flint      . 
Soft  White  Chalk 
Second  Pipeclay  . 
Hard  Chalk        . 

Soft  White  Chalk 
Wall  Stone 

Soft  Chalk  with_Horns 

Soft  White  Chalk 
Third  Pipeclay  . 

Hard  Chalk        . 
Floor  Stone . 


Soft  White  Chalk 


Hard  Chalk  .    K. 

Rough  and  Smooth  Blacks,    ss. 

Soft  White  Chalk       .        •    a*. 


;  si 


•M'  E*. 

~^r*c.". -, 


•r^fe? 


-OftLi^ 


I  iy* 


_-v] 


earliest  underground  workings  in  this  country  were  probably  for 
flint ;  and  secondly,  flint  affords  a  good  instance  of  the  replace- 
ment of  an  original  bed  by  another  mineral. 


MODE  OF  OCCURRENCE  OF  MINERALS.          41 

Pits  in  the  chalk  known  as  "  Grime's  graves,"*  were  at  one 
time  a  puzzle  to  the  antiquary,  but  it  is  now  generally  conceded 
that  they  are  the  mine  shafts  by  which  beds  of  flints  were  worked 
for  the  manufacture  of  stone  implements  in  Neolithic  times. 

This  old  trade  of  flint  mining  still  survives  at  Brandon  in 
Suffolk,  for  though  stone  hatchets  and  arrow-heads  are  no  longer 
wanted,  there  is  still  a  market  for  gun-flints  in  parts  of  Africa.  The 
mode  of  mining  the  stone,  splitting  off  flakes  and  knapping  them 
into  gun-flints  has  been  admirably  described  and  illustrated  by 
Mr.  Skertchlyf  in  one  of  the  "  Memoirs  of  the  Geological  Survey 
of  England  and  Wales."  Fig.  32  represents  a  section  of  the  beds 
in  which  the  flint  occurs.  It  shows  that  the  layers  of  flint  are 
sometimes  continuous,  and  sometimes  consist  merely  of  a  succession 
of  nodules  which  do  not  touch  each  other.  Some  of  the  flint  has 
knobs  and  even  horn-like  projections,  the  transformation  from 
chalk  into  silica  not  being  confined  strictly  to  one  particular  layer 
of  the  original  sea-bottom.  The  principal  bed  is  the  "  floor-stone," 
No.  20,  about  8  inches  thick,  but  other  layers  are  mined  from 
time  to  time  for  building  stone  or  gun-flints.* 

Freestone. — Freestone  is  largely  quarried  in  England  from 
beds  of  Jurassic  age,  and  the  so-called  "  Bath  stone  "  is  not  only 
quarried  but  also  mined  at  Corsham  in  Somersetshire,  and  at 
Weldon  in  Northamptonshire.  The  bed  worked  in  the  Corsham 
underground  quarries  varies  from  8  to  24  feet  in  thickness,  lying 
almost  flat ;  it  is  a  typical  oolitic  limestone  which  can  be  sawn 
freely  in  any  direction.§ 

Gold. — This  metal  is  so  widely  distributed  over  the  earth  that 
it  will  be  impossible  to  compress  into  the  space  at  my  disposal 
anything  more  than  a  very  summary  description  of  the  principal 
modes  of  occurrence  in  beds,  veins,  and  masses. 

Beds. — During  the  last  few  years  the  attention  of  cap- 
italists, miners,  and  geologists  has  been  often  directed  to  the 
marvellous  resources  of  the  Witwatersrand||  or  simply  "  Rand  " 
goldfield,  in  the  Transvaal  or  South  African  Republic,  and 
situated  about  35  miles  south  of  Pretoria,  the  capital.  The  gold 
is  obtained  entirely  from  beds  of  conglomerate  or  puddingstone 
called  banket,  which  is  the  Dutch  name  for  almond  rock,  the 
hardbake  of  the  British  schoolboy,  because  the  pebbles  look  like 

*  The  word  "  grave  "  no  doubt  corresponds  here  to  the  German  Graben, 
a  ditch  or  trench,  and  has  no  reference  to  burial. 

t  On  tlie  Manufacture  of  Gun-Flints,  &c.     London,  1879. 

+  A  more  or  less  regular  and  continuous  layer  of  flints  is  locally  called  a 
sase  or  sese,  which  recalls  the  French  word  "  assise." 

§  C.  Le  Neve  Foster,  "  Some  Mining  Notes  in  1887,"  Trans.  Min.  Assoc. 
and  Inst.  Cornwall,  vol.  ii.  p.  136.  Camborne,  1888. 

||  A  very  complete  summary  of  papers  upon  South  African  Geology  is 
given  by  Mr.  Gibson  in  his  memoir,  "  The  Geology  of  the  Gold-bearing  and 
Associated  Rocks  of  the  Southern  Transvaal,"  Quart.  Jour.  Geol.  Soc., 
vol.  xlviii.  (1892),  p.  406. 


ORE  AND  STONE-MINING. 


the  almonds  in  the  sugar.  The 
layers  of  auriferous  conglomerate 
lie  conformably  among  beds  of 
sandstone,  shale,  clay,  and  quartzite. 
At  Johannesburg  the  beds  strike 
east  and  west  and  dip  to  the  south. 
The  conglomerate  consists  mainly 
of  pebbles  of  white  quartz,  and  in 
the  upper  parts  of  the  workings 
they  are  cemented  together  by  oxide 
of  iron,  sand,  and  clay.  Below  the 
influence  of  atmospheric  agencies, 
the  cementing  material  is  found  to 
consist  largely  of  silvery-grey  mi- 
caceous matter  with  cubical  crystals 
of  iron  pyrites,  and  the  colour  of 
the  banket  changes  from  red  and 
brown  to  blue  and  bluish  grey.  It 
is  quite  evident  from  the  examina- 
tion of  specimens  that  much  of  the 
ferruginous  matter  in  the  upper 
parts  of  the  conglomerate  is  derived 
from  the  decomposition  of  iron 
pyrites,  and  visible  gold  is  seen  in 
the  cavities  formerly  occupied  by 
crystals  of  that  mineral.  The  bulk 
of  the  gold  is  said  to  exist  in  the 
cement  and  not  in  the  pebbles ;  but 
some  assays  made  by  the  late  Mr. 
Richard  Smith  show  that  this  is  not 
invariably  the  case. 

Fig.  33,*  a  section  across  the 
Salisbury  Mine  at  Johannesburg, 
shows  four  beds  of  auriferous  con- 
glomerate, known  respectively  as 
the  North  Reef,  the  Main  Reef,  the 
Main  Reef  Leader,  and  the  South 
Reef. 

As  would  naturally  be  expected 
in  the  case  of  beds  which  must  have 
been  deposited  in  shallow  water, 
there  are  frequent  variations  of 
character  and  thickness  in  a  short 
distance. 

Whilst  certain  beds  of  conglome- 
rate are  auriferous,  others  are  not, 

*  Gibson,  Ibid.  p.  411. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


43 


or  contain  merely  traces  of  gold.  The  sandstone,  as  a  rule,  is 
not  auriferous,  but  layers  within  the  banket  may  be  worth 
working.  The  richest  beds  are  the  Main  aijd  South  Reef  with 
some  of  the  thin  "  leaders."  The  gold  is  not  distributed 
uniformly  through  the  bed  of  banket ;  but  upon  the  whole  there 
ib  far  greater  regularity  of  yield  than  can  be  expected  in  a  vein, 
and  as  a  rule  the  whole  of  the  bed  is  worked  away  like  a  seain  of 
coal,  without  poor  portions  being  left.  The  fact  of  being  able  to 
form  a  rough  approximate  estimate  of  the  probable  yield  of  a 
given  area  of  banket  is  of  the  utmost  commercial  importance. 

The  Rand  output  in  1892*  was  1,210,865  ounces  of  bar  gold  ; 
the  average  total  yield  of  the  conglomerate  stamped  was  12  J  dwt. 
of  gold  per  ton,  of  which  about  four-fifths  were  obtained  at  once 
by  amalgamation  at  the  mills,  and  one-fifth  by  subsequent  treat- 
ment of  the  tailings  and  concentrates. 

The  gold-bearing  strata  are  supposed  to  be  of  Devonian  age. 

Whether  the  gold  was  deposited  at  the  same  time  as  the 
pebbles  of  quartz,  or  whether  it  was  brought  by  the  subsequent 


FIG.  34. 


a,  hard  grey  siliceous  shale  :  6,  massive  qtiartzite,  becoming 
talcose  and  highly  auriferous  in  zones  ;  c,  schistose  quartzite, 
becoming  argillaceous  in  places  ;  d,  impure  sandstone  quartzite, 
e,  quartzose  breccia  with  fragments  of  felsite  and  clay  shale ;  /, 
hard  grey  siliceous  shale ;  </,  highly  auriferous  sandy  matter 
resulting  from  the  disintegration  of  the  bed  I. 

infiltration  of  mineral  solutions  which  found  their  easiest 
channels  of  escape  through  the  most  readily  permeable  beds,  has 
not  been  decided;  but  where  the  bulk  of  a  deposit  consists  of 

*  Phillips,  "Address  to  the  Rand  Chamber  of  Mines,"  January  26th 
1893- 


44 


ORE  AND  STONE-MINING. 


materials  of  undoubted  sedimentary  origin,  it  is  best  for  the 
miner  to  call  it  a  "  bed  "  or  "  seam,"  and  leave  the  question  of 
origin  to  be  settled  later  on  by  the  geologist. 

Fig.  34  represents  a  section  of  the  Sheba  mine,  Barberton,* 
where  the  gold  is  obtained  from  a  bed  of  auriferous  quartzite. 

Fig.  35  is  a  section  of  an  auriferous  alluvium  in  the  Caratal 
district  of  Venezuela,  f 


FIG.  35. 


The  following  is  the  succession  of  the  beds : — i.  Soil.  2.  Red 
clay,  showing  no  signs  of  stratification.  3.  Soft  clayey  "  moco  de 
hierro."  4.  Hard  brown  iron  ore  ("moco  de  hierro"),  with 
pieces  of  quartz  in  it  and  a  little  clay.  5.  Blocks  of  vein-quartz, 
often  auriferous.  6.  "Greda,"  or  pay-dirt,  a  yellow  ferruginous 
clay  containing  nuggets  and  small  grains  of  gold.  7.  "  Cascajo," 
decomposed  schist,  forming  the  "bed-rock." 

Fig.  36  explains  how  a  superficial  gold-bearing  "rain wash" 
may  result  from  the  denudation  of  a  bed  of  auriferous  gravel. 

Some  of  the  deposits  of  gold  in  Brazil  occur  under  totally 
different  conditions.  The  precious  metal  is  found  in  beds  of 
jacotinga,  the  local  name  for  a  friable  mixture  of  micaceous  iron, 
earthy  brown  iron  ore,  oxide  of  manganese,  lithomarge  or  talc,  a 
little  quartz,  and  small  lumps  and  granules  of  gold.  The  beds  of 
jacotinga  occur  as  subordinate  bands  in  the  rock  known  as 
itabirite,  composed  mainly  of  micaceous  iron,  specular  iron,  mag- 


*  MS.  of  C.  J.  Alford,  F.G.S. 

t  C.  Le  Neve  Foster,  "  On  the  Caratal  Gold-field,' 
Soc.,  vol.  xxv.  1869,  p.  340. 


Quart.  Jour.   Geol. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


45 


netite,  and  granular  quartz.     Some  of  the  beds  of  itabirite  are 
worked  as  iron  ores. 

FIG.  36. 


i.  Schist  ("Cascajo  ")  or  felstone  forming  the  bed-rock  of  a  fer- 
ruginous gold-bearing  gravel  ("moco  de  hierro")  2  ;  3.  Ked  fer- 
ruginous earth  ("  Tierra  de  flor  ")  containing  nuggets  of  gold. 

Though  the  jacotinga  forms  beds,  the  gold  is  not  uniformly  dis- 
tributed through  it,  but  is  concentrated  in  productive  shoots. 

Veins. — The  veins  usually  consist  in  great  part  of  quartz,  and 
contain  in  addition  iron  pyrites,  or  some  other  heavy  metallic  sul- 
phides, such  as  galena,  zinc  blende,  copper  pyrites,  magnetic  pyrites, 
stibnite  and  mispickel.  The  gold  is  principally  in  the  metallic 
state,  even  when  enveloped  in  pyrites,  which  is  so  frequently  the 
case ;  but  it  occurs  also  in  combination  with  tellurium,  and  with 
bismuth. 

The  "  Great  Quartz  Vein,"  or  "  Mother  Lode,"  in  the  Sierra 
Nevada  of  California  is  the  first  deposit  that  must  be  noticed; 
for  it  is  remarkable  by  its  length,  its  width,  the  number  of 
mines  which  are  dependent  upon  it,  and  their  annual  yield  of 
the  precious  metal.  Some  of  the  most  important  facts  concerning 
it  have  been  described  by  Whitney.*  The  axis  of  the  Sierra 
Nevada  is  a  mass  of  intrusive  granite,  which  is  flanked  by  meta- 
morphic  Triassic  and  Jurassic  rocks  ;  the  existence  of  fossils  proves 
the  gold-bearing  strata  to  be  of  Secondary  age.  The  rocks  in 
which  the  principal  gold  veins  of  this  region  occur,  are  slates 
of  various  kinds,  such  as  clay-slate,  talcose  slate  and  chloritic 
slate,  which  form  a  marked  belt,  sometimes  18  miles  wide,  running 
through  the  country  for  fully  150  miles.  The  slates  are  accom- 
panied by  a  band  of  serpentine  sometimes  a  mile  wide.  "  Asso- 
ciated with  the  serpentine  is  the  very  remarkable  mass  of  quartz 
known  as  the  '  Great  Quartz  Vein,'  which  may  be  traced  for  a 
distance  of  80  miles  from  Amador  County  to  Mariposa  County  in 
a  general  S.E.  by  S.  direction."t  "This  powerful  lode  is  made 
up  of  irregularly  parallel  plates  of  white  compact  quartz  and 
crystalline  dolomite  or  magnesite,*  more  or  less  mixed  with 

*  The  Auriferous  Gravels  of  the  Sierra  Nevada  of  California.  Cambridge, 
U.S.,  1880,  p.  45. 

f    Op.  Git.  p.  46. 

J  Whitney  adds  the  note — "  In  the  only  specimen  which  has  thus  far 
been  chemically  examined,  the  supposed  dolomitic  portion  proved  to  be 
an  intimate  mixture  of  quartz  and  magnesite. " 


46  ORE  AND  STONE-MINING. 

green  talc;  and  these  plates,  which  somewhat  resemble  the 
1  combs '  of  ordinary  lodes,  are  either  in  contact  or  separated  from 
each  other  by  intercalated  layers  of  talcose  slate."  "  The  quartz 
is  the  auriferous  portion  of  the  lode,  although  it  is  far  from  being 
uniformly  impregnated  with  gold."  "  The  talcose  slate  bands  in 
the  vein  are  often  themselves  more  or  less  auriferous."  In  one 
place  the  vein  is  261  feet  wide  measured  horizontally  across  it, 
and  it  dips  to  the  north-east  at  an  angle  of  60°.  Whitney  says 
it  is  not  proved  to  be  a  fissure  vein,  and  he  is  more  inclined  to 
consider  it  as  a  metamorphosed  belt  of  rock. 

The  map  of  the  lode  given  by  Collins,*  shows  seventy-seven 
mines  which  are  now  being  worked,  or  which  have  been  profitably 
worked  in  recent  times,  and  \ye  learn  from  him  that  the  auri- 
ferous quartz  contains  small  quantities  of  metallic  sulphides,  such 
as  iron  pyrites,  mispickel,  marcasite,  chalcopyrite,  and  galena, 
The  quantity  of  gold  produced  from  the  quartz  treated  varies  from 
3  dwts.  to  15  or  20  dwts.  per  ton,  and  the  "Great  Quartz  Vein" 
or  "  Mother  Lode  "  is  estimated  to  yield  about  two  million  dollars 
worth  of  gold  annually. 

The  gold  veins,  or  "  reefs,"  in  Victoria  are  found  in  the  Upper 
and  Lower  Silurian  rocks.  The  gold  is  especially  associated  with 

FIG.  37. 


|71>-r:g|  SLATE 

SADDLE. 


fcvX.  •-;'  :  QUARTZ 


iron  pyrites ;  when  it  decomposes  a  cellular  honeycombed  quartz 
is  left  behind,  and  the  gold  is  unmasked  and  rendered  visible 
in  the  little  rusty  cavities.  Other  heavy  metallic  sulphides  are 
common  here  as  elsewhere. 

The  peculiarities  of  the  so-called  "saddle-reefs"  of  the  Sand- 

*  "  Notes  on  the  Great  Mother  Lode  of  California,"  Jour.  Roy.  Inst. 
Cornwall.     Truro.     Vol.  ix.  (1886),  p.  64. 


MODE  OF  OCCURRENCE  OF  MINERALS.          47 


hurst  or  Bendigo  gold-field,  Victoria,  which  differ  considerably 
from  typical  veins,  have  been  very  clearly  explained  by  Mr.  T. 
A.  Rickard,*  from  whose  useful  memoir  the  following  account  is 
borrowed.  These  reefs  are  arch-like  masses  of  quartz  conform- 
able to  the  bedding  of  the  surrounding  Lower  Silurian  slate  and 
sandstone,  as  shown  by  the  letters  BACin  Fig.  37.  The  part 
A  is  called  the  "  cap  "  or  "  apex  " ;  B  is  the  "  west  leg  "  and  C  the 
"  east  leg,"  because  the  main  anticlinal  axes  strike  N.N.W.  and 
S.S.E.  The  part  D  is  known  as  the  "  centre  country,"  the  rocks 
to  the  east  of  C  form  the  "  east  country,"  and  those  to  the  west 
of  B  the  "  west  country."  The  inclination  of  the  line  of  the 
ridge,  northwards  or  southwards,  is 
spoken  of  as  the  "  pitch,"  in  order  to  FIG.  38. 

distinguish  it  from  the  dip  of  the 
strata.  There  may  be  more  than  one 
such  saddle,  or  a  long  succession  of 
them,  one  below  the  other  (Fig.  38), 
but  they  are  not  all  equally  auriferous. 
Trms,  out  of  five  which  have  been 
discovered  and  explored  at  "  180" 
mine,  only  three  have  proved  to  be 
worth  working  for  gold. 

Similar  masses  of  auriferous  quartz 
have  been  found  at  some  of  the 
synclines  ("inverted  saddles"),  and 
worked  to  a  slight  extent.  Very 
large  dividends  have  been  paid  by 
many  of  the  companies  working  the 
"  saddle-reefs." 

Masses.  —  Having  given  examples 
of  auriferous  beds  and  veins,  I  come 
to  masses.  Tread  well  mine,f  situated  SADDLES 

on  Douglas  island,  Alaska,   owes  its 

•existence  to  a  mass  of  auriferous  altered  granite,  400  feet  wide 
and  of  considerable  length.  The  rock,  which  appears  to  have 
been  a  hornblende  granite  originally,  now  consists  principally  of 
•quartz  and  felspar,  with  a  little  calcite  and  specks  of  iron  pyrites, 
and  it  is  traversed  by  strings  of  quartz,  iron  pyrites,  and  calcite. 
The  original  rock  was  probably  crushed  and  fissured,  and  then 
brought  under  the  action  of  solutions  which  penetrated  into  it 
in  all  directions,  and  so  produced  the  alteration.  The  yield  is 
considerably  less  than  J  oz.  per  ton,  but  as  the  deposit  can  be 

*  "The  Bendigo  Gold-Field,"  Trans.  Amer.  Inst.  M.E.,  vol.  xx.  (1891), 
p.  463. 

t  G.  M.  Dawson,  "  Notes  on  the  Ore-deposit  of  the  Treadwell  Mine, 
Alaska,''  American  Geologist,  1889,  p.  84;  and  Frank  D.  Adams,  "On  the 
Microscopical  Character  of  the  Ore  of  the  Treadwell  Mine,  Alaska,"  Ibid. 
p.  88. 


48 


ORE  AND  STONE-MINING. 


worked  opencast,  the  cost  of  getting  is  low.  Much  of  the  gold  is 
free,  and  can  be  extracted  by  amalgamation  in  spite  of  its  being 
enveloped  by  pyrites. 

This  mass  may  be  called  a  stock  work  or  net- work  deposit. 

The  productive  Mount  Morgan  mine,*  near  Rockhampton,  in 
Queensland,  while  astonishing  the  world  by  its  richness,  affords  a 
puzzle  to  geologists  which  has  not  yet  been  satisfactorily  solved. 

The  auriferous  deposit,  which  is  worked  as  an  open  quarry,  is  a 
mass  of  brown  haematite,  sometimes  stalactitic  and  containing  a 
little  silica,  which  passes  gradually  into  a  ferruginous  siliceous 
sinter.  Some  of  it  is  spongy  and  frothy  in  appearance,  and  so 
full  of  cavities  that  it  will  float  upon  water  like  pumice.  The 
precise  nature  of  the  gold-bearing  mass  is  well  illustrated  by 
twenty  views  which  accompany  the  "  Third  Report "  of  Mr. 
R.  L.  Jack,  the  Government  geologist. 

Both  the  sinter  and  the  brown  iron  ore  contain  gold,  and 
yield  on  assay  several  ounces  to  the  ton.  The  auriferous  stone 

FIG.  39. 


«,  pipe  of  geyser  (theoretical)  ;  b,  cup-deposit  of  geyser  ;  c,  over- 
flow deposit  of  geyser  ;  s,  metamorphic  rocks  ;  d,  rhyolite  dykes. 

caps  a  hill  rising  about  500  feet  above  the  neighbouring  table- 
land, and  the  most  important  part  of  it  is  the  actual  top  or  crown, 
an  oval  mass  300  yards  long  by  170  yards  wide. 

Mr.  Jack  considers  that  the  deposit  is  the  product  of  a  geyser, 
and  he  explains  his  views  by  the  section  (Fig.  39).  This  naturally 
represents  the  present  condition  of  the  hill,  much  of  the  original 
geyser  deposit  being  supposed  to  have  been  removed  by  denu- 
dation. 

The  gold  exists  in  a  state  of  great  fineness,  and  the  metal 
extracted  is  of  extreme  purity,  for  it  contains  99-7  of  gold, 
the  rest  being  copper,  a  trace  of  iron,  and  a  minute  trace  of 
silver.  Dr.  Leibius,  of  the  Sydney  Mint,  speaks  of  it  as  the 
richest  native  gold  hitherto  found. 

Without  having  examined  the  deposit  upon  the  spot,  one 
scarcely  likes  to  criticise  the  conclusions  of  so  able  an  observer 
as  Mr.  Jack;  but  looking  at  his  section  of  the  No.  i  tunnel, 
we  find  that  the  auriferous  mass  must  repose  upon  highly 
pyritous  rocks,  such  as  quartzite  full  of  fine  pyrites,  in  which  the 
latter  constituent  may  sometimes  predominate.  The  suspicion 

*  R.  L.  Jack,  "  Mount  Morgan  Gold  Deposits."  Brisbane,  1884.  Second 
Report,  1889  ;  and  Third  Report,  1892. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


49 


naturally  crosses  one's  mind  that  the  gold-bearing  cap  may  simply 
be  due  to  the  decomposition  and  weathering  of  the  pyritiferous 
rock.  Mr.  Jack  combats  this  theory,  and  says  that  it  is  dis- 
proved by  three  facts :  ist.  A  dyke  of  dolerite  in  the  quartzite 
does  not  reach  up  into  the  overlying  sinter.  2nd.  The  pyri- 
tiferous quartzite  is  poor  in  gold.  3rd.  The  silica  of  the  sinter  is 
hyd rated.  He  therefore  still  maintains  his  original  opinion  that 
the  sinter  and  ironstone  were  deposited  by  a  thermal  spring  on 
the  pyritous  quartzite,  and  are  not  altered  portions  of  it.* 

Mr.  Rickard,f  while  disagreeing  with  the  geyser  theory, 
concurs  in  Mr.  Jack's  opinion  that  the  deposit  is  not  an  altered 
portion  of  the  pyritous  quartzite,  though  he  remarks  that  the 

FIG.  40. 


Mount  Morgan  rock  bears  a  strong  outward  resemblance  to  the 
decomposed  outcrop  of  the  Broken  Hill  lode  in  New  South  Wales. 
This  can  be  easily  imagined  from  an  inspection  of  the  views  given 
in  Mr.  Jack's  third  report,  from  which  the  outlines  of  Fig.  40 
have  been  copied.  The  theory  propounded  by  Mr.  Rickard 
(Fig.  41)  is  that  the  auriferous  stone  of  Mount  Morgan  is  rock 
shattered  by  the  intrusion  of  dykes,  and  then  altered  by  the  per- 
colation of  underground  mineral  solutions,  which  found  an  easy 
passage  through  the  cracked  and  fissured  mass.  He  points  out 
that  the  gold  may  have  been  derived  from  the  poor  pyrites 
disseminated  through  the  quartzite,  or  from  the  sandstone  of  the 
district,  which  has  been  shown  to  be  auriferous. 

The  quantity  of  stone  treated  by  chlorination  at  Mount  Morgan 

*  Second  Report,  p.  4. 

t  "  Mount  Morgan  Mine,  Queensland,"  Trans.  Amer.  Inst.  M.E.  vol.  xx. 
(1891),  p.  133. 

D 


50  ORE  AND  STONE-MINING. 

in  the  twelve  months  ended  ^oth  November,   1889,  was  75,415 
tons,  from  which  323,542  oz.  of   gold   were  obtained,  equal  to 

FIG.  41. 


MOUNT  MORGAN  SECTIONS. 

based  on  late  developments 
!•:-...• .-.,  •••'•••.:'.|    ORE  DEPOSIT.  INTERSECTED  BY  SMALL  DYXES  NOT  SHOWN  R^^-M     pyRfTIOUS  OUARTZITE     P"V"'y;-''J    CYR33 

4  oz.  6  dwt.  per  ton.  The  gold  was  sold  for  ^1,33 1,484,  and 
j£i,  1 00,000  was  paid  in  dividends. 

Graphite. — The  great  graphite  mines  of  the  world  are  those 
of  Ceylon,  where  the  mineral  is  found  in  layers  from  a  few  inches 
to  several  feet  in  width,  in  gneiss  and  mica  schist.  The  graphite 
is  associated  with  quartz  and  a  little  iron  pyrites. 

There  are  various  graphite  deposits  in  Austria  and  Bavaria.* 
At  Kaiserberg,  in  Styria,  the  mineral  is  found  in  graphitic  schist ; 
the  beds  vary  in  thickness  very  rapidly  from  a  few  inches  to  20  feet. 

In  Lower  Austria,  Moravia,  Bohemia,  and  Bavaria  graphite 
occurs  in  gneiss  usually  accompanied  by  granular  limestone.  The 
Passau  graphite  is  in  the  form  of  small  black  scales,  and  appears 
to  take  the  place  of  some  of  the  mica  in  a  highly  felspathic  gneiss  ; 
the  thickness  of  the  beds  varies  greatly,  but  may  be  as  much  as 
1 6  feet  (5  m). 

The  Bavarian  mines  produced  3352  tons  of  graphite  in  1888. 

Gypsum. — As  one  of  the  principal  uses  of  gypsum  is  for 
making  plasber-of-paris,  we  naturally  turn  to  the  French 
metropolis  for  an  example  of  the  mode  of  occurrence  of  this 
mineral.  The  gypsum  is  found  in  beds  from  50  to  60  feet  thick, 
which  are  of  Upper  Eocene  age  (Fig.  352). 

In  England  and  elsewhere,  the  Triassic  rocks  have  long  been 
remarkable  for  containing  valuable  beds  of  gypsum,  and  they  are 
largely  worked  in  Derbyshire  and  Nottinghamshire.  Fig.  42  re- 
presents the  layers  of  nodules  in  a  gypsum  mine  at  Kingston-on- 
Soar,  Nottinghamshire.  There  are  three  beds  a  few  feet  apart  in 
the  New  Red  Marl.  The  bottom  bed  consists  of  large  spheroidal 
masses,  varying  from  5  to  8  feet  in  thickness,  and  5  to  10  feet  in 
diameter ;  above  it  are  two  layers  of  "  balls  "  and  nodules,  more 
or  less  continuous.  The  highly  gypsiferous  marl,  locally  called 

*  Th.  Andree,  "Der  osterreichische  und  bayerische  Graphitbergbau," 
B.  u.  h.  Z.  1890,  p.  269. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


FIG.  42. 


"  fault,"  B,  between  the  big  balls,  A  A,  is  left,  so  as  to  form  pillars, 
which  support  the  roof  of  the  workings. 

White  translucent  alabaster  for  statuary  purposes  is  mined  at 
Castellina  Marittima,*  in  the  province  of  Pisa.  Its  mode  of 
occurrence  resembles  that  just  de- 
scribed, for  it  is  found  in  irregular 
spheroidal  or  kidney-shaped  masses 
called  "ovuli"  by  the  workmen,  from 
a  few  inches  to  several  feet  in  dia- 
meter, and  occasionally  weighing 
more  than  a  ton  each.  The  grey 
marl  surrounding  the  nodules  is  of 
Pliocene  age.  The  alabaster  is  sac- 
charoidal  and  very  fine  grained. 

Ice. — By  some  per  sons  this  mineral 
maybe  considered  beneath  notice,  but 
the  trade  in  ice  is  so  large  that  it 
deserves  at  least  a  passing  mention. 
The  United  States  f  are  the  largest  METRt  Trf"  '*.  ','  '^  f  IMC™* 
producers  of  natural  ice  in  the  world, 

arid  in  some  years  12,000,000  tons  are  gathered  from  the  lakes 
and  rivers,  and  especially  from  the  Hudson.  The  gathering  in  of 
the  ice  crop  affords  employment  to  "  12,000  men  and  boys,  1,000 
horses,  and  100  steam  engines."  Much  ice  is  exported  from 
Boston,  and  Norway  also  is  a  country  with  a  large  ice  trade. 

Iron. — This  metal  is  very  widely  distributed  over  the  globe, 
and  affords  examples  of  many  modes  of  occurrence,  though  veins 
of  iron  ore  are  quite  driven  into  the  background  by  the  yield  of 
beds,  and  especially  those  of  the  Jurassic  age. 

The  most  productive  European  deposits  at  the  present  time 
are  :  the  bed  of  iron  ore  in  the  Cleveland  district,  the  masses  of 
red  haematite  in  Cumberland  and  North  Lancashire,  the  bed  of 
brown  haematite  in  German  and  French  Lorraine,  and  Luxem- 
burg, and  the  beds  of  red  and  brown  haematite  near  Bilbao,  in 
Northern  Spain. 

The  bed  of  ironstone  worked  in  the  Cleveland  district  of  North 
Yorkshire  is  found  in  the  Middle  Lias.  Mr.  Kendall  J  gives  the 
following  general  section  of  the  rocks : — 

*  Jervis,  Itesori  sotterranei  deW  Italia,  vol.  ii.  p.  419,  and  vol.  iv.  p.  318. 

t  "The  Trade  in  Ice,"  Jour.  Soc.  Arts.  London,  1890,  vol.  xxxviii. 
p.  765. 

J  "  The  Iron  Ores  of  the  English  Secondary  Kocks,"  Trans.  N.  of  Eng. 
Inst.  Min.  Eng.,  vol.  xxxv.  (1886),  p.  113.  Barrow,  "The  Geology  of  North 
Cleveland,"  Mem.  Geol.  Survey,  1888. 


ORE  AND  STONE-MINING. 


Description. 

Thick- 
ness. 

Characteristic  Ammonite. 

/Shale     with     cement    stone 

ft.  in. 

TT                  nodules  (alum  shale  series) 

115  o 

A.  communis 

upper    j  ghale  with  doggers*  Qet  rock 

Llas           series)          .... 

48  o 

A.  serpentinus 

^Grey  shale  with  doggers 

30  o 

A.  annulatus 

r  Ironstone  (Main  seam)  . 
Shale  with  doggers 

ii  6 

10  6 

.A.  spinatus 

Ironstone  (bottom  seam) 

2  9 

s 

Shale  with  nodules  of  clay 

Middle  . 

ironstone     .... 

20   0 

Lias 

Ironstone  in  thin  bands 
Shale        with        ferruginous 

i  9 

-A.  margaritatus 

doggers      .... 

30  o 

Sandstone,  sometimes  flaggy, 

*     calcareous,  and  ferruginous 

40  o 

"\  A.    capricornus,   Ja- 

T             [Shale    with    numerous    thin 
ijower   j     limestones    in    the    lowest 
Lias      I     300  feet      .... 

700  o 

mesoni,     armatns, 
-     oxynotus,      Buck- 
landi,      angulatus, 

and  planorbis 

Fig.  43!  illustrates  sections  of  the  bed  at  Eston  and  Upleatham. 

FIG.  43- 


Grey  shale  and  ferruginous  nodules 

Ironstone  (top  block)  in  alternate  hard  and]      ^2, 
soft  layers,  not  worked       ...  j 


Ironstone  (main  block],  -workable  part  of  bed  \     ^oVf 
at  present )      ^^ 


Ironstone  (bottom  block)  not  worked       .         .       i  JO 
Shale  


The  Main  Seam  practically  furnishes  all  the  Cleveland  ore.     It 
probably  extends  over  an  area  of  350  square  miles,  though  it 

*  Doggers  are  nodules  of  ironstone, 
t  Kendall,  Op.  cit.     Fig.  5,  Plate  XIII. 


MODE  OF  OCCURRENCE  OF  MINERALS.          53 

cannot  be  profitably  worked  over  anything  like  the  whole  of  this 
district.  The  average  thickness  where  worked  is  about  10  feet. 
The  beds  dip  very  gently  about  i  in  15,  to  the  south-east.  The 
seam  is  thickest  and  best  at  Normanby,  Eston,  and  Upleatham  ; 
in  proceeding  to  the  south-east,  partings  of  shale  appear,  and 
split  up  the  main  seam  into  numerous  comparatively  thin  layers 
of  ironstone,  with  a  smaller  percentage  of  metal.  Some  of  the 
ironstone  is  oolitic  and  of  a  greenish  grey  colour,  but  much  of  it 
is  not  oolitic,  and  is  bluish  grey  in  colour,  resembling  a  mudstone. 
The  iron  exists  chiefly  as  carbonate,  some  of  which,  according  to 
Dr.  Sorby,  was  deposited  mechanically,  whilst  the  rest  was  formed 
chemically  by  replacement  of  carbonate  of  lime.  As  a  general 
average,  it  may  be  said  that  the  ore  contains  30  per  cent,  of 
iron.  The  district  produced  5,128,303  tons  of  ore  in  1891. 

The  masses  of  red  haematite  worked  in  Cumberland  and  North 
Lancashire  have  already  been  noticed  (Fig.  14). 

The  great  iron-field  of  Lorraine,*  much  of  which  became  the 
property  of  Germany  in  1871  after  the  Franco-Prussian  war, 
stretches  out  from  Nancy  past  Metz  and  Diedenhofen  into 
Luxemburg.  It  may  be  called  60  miles  long  by  10  to  12  miles 
wide  (100  km.  by  15  to  20  km.). 

The  iron-bearing  strata  belong  to  the  Lower  Dogger  or  Brown 
Jura  (Inferior  Oolite),  and  consist  of  marly  sandstone,  marl  and 
sandy  clay,  interstratified  with  beds  of  limestone  and  iron  ore. 

In  places  there  is  no  iron,  and  in  others,  especially  in  the  south 
and  on  the  eastern  edge,  the  beds  of  ore  are  thin.  On  the  other 
hand,  at  Esch,  in  Luxemburg,  four  beds  of  iron  ore  and  their 
partings  of  limestone  and  sandstone  make  up  a  total  thickness  of 
65  feet  (20  m.),  and  at  Deutsch-Och  and  Oettingen  three  beds  and 
the  partings  are  32  feet  (10  m.)  thick;  then  at  Hayingen  the  total 
thickness  sinks  to  20  feet  (6  m.),  and  at  Ars  there  is  only  one  bed 
5  to  6  feet  thick.  The  strata  are  slightly  undulating,  but  the 
general  dip  is  i  to  2\  in  a  hundred  to  the  south-west.  The  iron 
exists  in  the  state  of  hydrated  oxide,  probably  for  the  most  part 
as  2Fe2033H20,  which  constitutes  the  roe-like  grains  which  are  so 
characteristic  of  the  ore. 

The  oolitic  particles  are  enclosed  in  a  calcareous  matrix,  which 
may  contain  quartz.  The  matrix  is  always  more  or  less  ferru- 
ginous, and  sometimes  consists  of  a  greenish  mineral,  which  is 
probably  a  silicate  of  iron.  The  ore  has  usually  from  32  to  38 
per  cent,  of  iron  and  from  J  to  2  per  cent,  of  phosphorus ;  there  is 
also  a  little  sulphur,  due  to  occasional  small  strings  of  iron 
pyrites.  The  name  "  minette,"  or  "  little,  unimportant  ore,"  was 
given  many  years  ago  to  this  bed  in  contradistinction  to  the 

*  Wandesleben,  "  Das  Vorkommen  der  oolithischen  Eisenerze  (Minette) 
in  Lotbringen,  Luxemburg  und  dem  Sstlichen  Frankreich."  Der  IV.  All- 
gemeine  Deutsche  Bergmannstag  in  Halle  (Saale}.  Fesiberkltt  und  Ver- 
handlungen,  Halle,  1890,  p.  297. 


TT  TvT  T  \r  T-.  -—• 


54 


ORE  AND  STONE-MINING. 


"  mine"  or  "  mineral  de  fer  fort,"  a  much  richer  ore  found  in  the 
neighbourhood,  which  is  now  no  longer  worked. 

Nearly  a  hundred  blast  furnaces  are  dependent  upon  the 
"  minette  "  for  their  supplies  of  ore,  and  in  1888  they  produced 
2,500,000  tons  of  pig  iron, .or  40  per  cent,  of  the  total  production 
of  Germany,  Luxemburg,  and  France.  More  than  four-fifths  of 
all  the  iron  ore  raised  in  this  last  country  is  obtained  from  this 
bed.  The  amount  of  ore  still  available  in  German  Lorraine  is 
estimated  at  2,100  million  tons,  or  enough  to  maintain  the  pre- 
sent rate  of  production  for  750  years. 

Sweden  is  justly  famous  for  its  great  deposits  of  magnetite. 
These  are  generally  lenticular  masses,  often  similar  in  shape  to 
the  Rio  Tinto  copper  veins,  and  enclosed  by  highly  metamorphosed 
rocks,  such  as  gneiss,  mica  schist,  and  the  hard  compact  hcilleflinta 
of  the  Swedish  geologists. 

It  would  not  be  right  to  quit  the  subject  of  iron  ore  without 
mentioning  at  least  one  of  the  mines  situated  in  the  neighbour- 
hood of  Lake  Superior,  where  the  Menominee,  Gogebic,  Vermilion 
and  Mesabi  districts  are  producing  large  quantities  of  mineral. 

At  Chapin  Mine*  near  the  town  of  Iron  Mountain  (Mich.) 
there  are  huge  lenticular  masses  of  haematite,  which  lie  parallel 
to  the  enclosing  Huronian  strata  (Fig.  44).t  One  large  lens  is 

FIG.  44. 


half  a  mile  long,  130  feet  wide  in  the  middle,  and  gradually 
tapering  out  to  a  point  at  each  end ;  it  strikes  15°  N.  of  W.,  and 
dips  from  70°  to  80°  N.,  and  the  axis  of  the  lens  pitches  30°  W. 
The  ore  contains  about  63  per  cent,  of  metallic  iron,  and  only 
o'07  per  cent,  of  phosphorus. 

*  Larsson,  "The  Chapin  Iron-mine,  Lake  Superior,"  Trans.  Amer.  Inst. 
M.E.,  vol.  xvi.  (1887),  p.  119. 
t  Engineering,  vol.  1.  (1890),  p.  552. 


MODE  OF  OCCURRENCE  OF  MINERALS.          55 

Lead. — Though  lead  ore  is  largely  wrought  from  veins,  one  of 
the  great  mines  in  the  world  obtains  its  supplies  from  a  bed.  The 
lead-bearing  sandstone  at  Mechernich,  in  Rhenish  Prussia,*  is  of 
Triassic  age  (Bunter)  and  is  on  an  average  nearly  100  feet  thick. 
It  rests  upon  and  is  covered  by  conglomerate,  and  is  often  split  up 
into  two  or  more  beds  by  thick  partings  of  conglomerate.  The 
ore  exists  in  the  form  of  little  concretions  of  galena  and  grains  of 
quartz,  but  these  are  not  uniformly  distributed  through  the  sand- 
stone. The  concretions  are  from  ^  inch  (i  mm.)  to  J  inch  (3  mm.) 

FIG.  45. 


Jt.lOO 


A,  greywacke  ;  B,  conglomerate  ;  C,  lead-bearing  sandstone ; 
D,  conglomerate;  E,  so-called  "red  rocks,"  consisting  of  red, 
yellow,  and  white  sandstone,  with  variegated  shales  and  clay. 

in  diameter,  and  are  harder  than  the  surrounding  sandstone, 
which  is  generally  very  friable.  When  the  rock  is  pulverised 
the  little  shot-like  masses  remain,  and  are  called  "knots"  (Knotten), 
whence  the  name  "  Knottensandstein  "  given  to  the  bed.  The 
amount  of  metallic  lead  in  the  sandstone  is  between  2  and 
3  per  cent. ;  but  the  concretions  themselves  contain  from  20  to  24 
per  cent.  According  to  the  statement  of  accounts  presented  to 
the  shareholders,t  the  average  percentage  of  lead  contained  in 
the  whole  of  the  sandstone  treated  in  1890  was  2*318;  347,706 
cubic  metres  (454,806  cubic  yards)  of  sandstone,  were  raised  from 
the  mine  and  open  work,  and  yielded  36,245  tons  of  lead  ore  for 
smelting  and  733  tons  of  potter's  ore.  This  would  be  at  the  rate 
of  io4kil.  of  dressed  ore  per  cubic  metre,  or  i  j  cwt.  per  cubic  yard, 
but  it  must  not  be  forgotten  that  the  bulk  of  the  ore — i.e.,  that 
which  goes  to  the  furnaces — is  not  highly  concentrated  and  con- 
tains only  54  per  cent,  of  metal.  The  proportion  of  silver  in  it  is 
5!  ounces  (180  grammes)  per  metric  ton. 

The  history  of  Leadville,  in  Colorado,  seems  like  a  romance 
when  we  read  of  the  rapid  development  of  the  mines,  the  creation 
of  a  large  and  important  town,  the  erection  of  smelting  works 
and  the  building  of  railways,  under  very  adverse  conditions,  in 

*  Der   Bergbau  und  Hutteiibetrieb    cles   Jfechernichtr  Bergwerlcs-Actieii- 
Vereins.     Cologne,  1886. 
t  Mining  Journal,  vol.  Ixi.  (1891),  p.  499. 


ORE  AND  STONE-MINING. 


MODE  OF  OCCURRENCE  OF  MINERALS.  57 

the  heart  of  the  Rocky  Mountains,  all  within  the  space  of  four  or 
five  years.  It  affords  additional  proof  that  the  miner  is  the  true 
pioneer  of  civilisation.  The  Leadville  deposits  have  been  ad- 
mirably described  by  Mr.  S.  F.  Emmons,*  from  whose  exhaustive 
report  I  borrow,  not  only  the  following  facts,  but  also  a  section 
across  one  of  the  mines  (Fig.  46). 

The  principal  deposits  of  the  region  are  found  at  or  near  the 
junction  of  white  porphyry  with  the  underlying  Blue  Limestone, 
which  is  the  lowest  member  of  the  Carboniferous  formation. 
This  bed  is  about  150  or  200  feet  thick,  and  consists  of  dark-blue 
dolomitic  limestone.  At  the  top  there  are  concretions  of  black 
chert.  The  porphyry  occurs  in  intrusive  sheets,  which  generally 
follow  the  bedding,  and  almost  invariably  a  white  porphyry  is 
found  overlying  the  Blue  Limestone.  This  porphyry  is  of 
Secondary  age.  It  is  a  white  homogeneous-looking  rock,  com- 
posed of  quartz  and  felspar  of  even  granular  texture,  in  which  the 
porphyritic  ingredients,  which  are  accidental  rather  than  essen- 
tial, are  small  rectangular  crystals  of  white  felspar,  occasional 
double  pyramids  of  quartz,  and  hexagonal  plates  of  biotite  or 
black  mica.  Along  the  plane  of  contact  with  the  porphyry  the 
limestone  has  been  transformed,  by  a  process  of  gradual  replace- 
ment, into  a  so-called  "  vein  "  consisting  of  argentiferous  galena, 
cerussite,  and  kerargyrite,  mixed  with  the  hydrous  oxides  of  iron 
and  manganese,  chert,  granular  cavernous  quartz,  clay,  heavy  spar, 
and  "  Chinese  talc,"  a  silicate  and  sulphate  of  alumina.  The  vein 
seems  to  have  been  formed  by  aqueous  solutions,  which  took  up 
their  mineral  contents  from  the  neighbouring  eruptive  rocks,  and 
brought  about  the  alteration  of  the  limestone  as  they  percolated 
downwards  through  it.  In  Carbonate  Hill  a  gradual  passage  may 
be  observed  from  dolomite  into  earthy  oxides  of  iron  and  manga- 
nese. The  masses  of  workable  ore  are  extremely  irregular  in 
shape,  size,  and  distribution.  They  are  often  from  30  tor  40  feet, 
thick  vertically,  and  occasionally  80  feet,  but  only  over  a  small 
area.  The  rich  ore  bodies  are  commonest  in  the  upper  part  of 
the  ore-bearing  stratum.  At  Fryer  Hill  the  Blue  Limestone  is 
almost  entirely  replaced  by  vein  material.  The  metallic  ores 
appear  to  have  been  deposited  originally  as  sulphides  ;  the  oxidised 
or  chloridised  ores  found  near  the  surface  are  the  products  formed 
by  the  percolation  of  surface  water  like  any  ordinary  gozzan. 

Manganese. — The  great  manganese-producing  countries  of  the 
present  day  are  Russia  f  and  Chili,  and  in  both  the  ore  is  derived 
from  beds,  and  not  from  veins  or  masses.  At  Tschiatoura  in  the 
Caucasus,  about  thirty  miles  from  Kwirilly  station  on  the  Poti- 
Tiflis  Railway,  there  are  beds  of  manganese  ore  of  Miocene  age. 
The  beds  worked  are  from  5  to  6  feet  thick  (1*5  m.  to  2  m.),  and 

*  Geology  and  Mining  Industry  of  Leadville,   Colorado.      Washington, 
1886. 
f  B.  u.  h.  Z.  1890,  pp.  32,  215. 


58  ORE  AND  STONE-MINING. 

are  made  up  of  several  small  seams  of  clean  manganese  ore, 
separated  by  partings  of  soft  sandstone  and  clay.  The  manganese 
exists  principally  in  the  form  of  Mn02,  and  the  ore  contains 
50  to  55  per  cent,  of  metal.  The  mines  are  at  present  heavily 
handicapped  by  the  long  and  expensive  carriage  to  Kwirilly 
station,  but  this  will  be  reduced  when  a  railway  is  made. 

Both  in  Wales  and  Belgium  there  are  beds  of  manganese  ore  in 
the  Cambrian  rocks.    The  Welsh  beds  are  about  a  foot  thick  (Fig. 

47),  sometimes  running  up  to 

FIG.  47-  1  8  inches  or  2  feet.    The  man- 

ganese is  principally  in  the 
form  of  carbonate,  though 
there  is  a  little  silicate,  and 
near  the  surface  these  have 
been  converted  into  hydrous 
oxides.  The  ore  is  inter- 
bedded  with  fine  -  grained 
sandstone,  hard  mudstone, 
and  shale,  also  manganifer- 
ous,  and  often  containing 
chlorite,  iron  pyrites,  and 
magnetite;  the  whole  man- 
ganiferous  series  is  enclosed 
in  the  regular  Cambrian  grits 
and  conglomerates.  The  ore 
contains  from  20  to  32  per 


H 


A,  fine-grained  sandstone  with  mag-    cent"  n^ganese. 
netite,  chlorite,   and  iron  pyrites  ;   13,         Marble.  —  The      famous 
manganese  ore  ;   C,  fine-grained  shaly    white     statuary     marble     of 
sandstone.  Italy  is  found  in  the  Apuan 

Alps  from   Carrara  to  Staz- 

zema,  on  the  S.W.  slope  of  the  mountains,  and  from  Frvizzanoto 
Vagli  Sotto  on  the  N.E.  slope.*  It  occurs  in  very  thick  beds, 
with  the  stratification  sometimes  well  denned,  but  generally 
completely  obliterated,  and  it  rests  upon  compact  limestone,  which 
in  its  turn  lies  upon  pre-palseozoic  mica-schist  and  talc-schist. 
The  age  of  the  marble  beds  has  not  been  ascertained  without 
doubt  ;  some  geologists  say  they  are  Triassic,  whilst  Jervis  calls 
them  pre-palseozoic. 

Mica.  —  This  mineral  is  obtained  in  North  Carolina  at  the 
present  time,  just  as  it  was  in  the  days  of  the  prehistoric  mound 
builders,  from  veins  of  giant  granite,  or  granite  in  which  the  con- 
stituent minerals  have  crystallised  on  a  huge  scale.  According  to 
Phillips,!  a  single  block  of  mica  has  weighed  nearly  a  ton,  and 

*  Jervis,  /  Tesori  soiterranei  dtW  Italia,  vol.  iv.  p.  261. 
t  "Mica  Mining  in  North  Carolina,"  Eng.  Min.  Jour.,  vol.  xlv.  (1888), 
p.  286. 


MODE  OF  OCCURRENCE  OF  MINERALS.          59 

pieces  6  feet  long  and  3  feet  wide  are  sometimes  met  with  ;  a  single 
crystal  of  felspar  weighing  800  Ib.  is  preserved  in  the  State 
Museum  at  Raleigh.  The  veins  are  from  30  to  40  feet  wide,  and 
are  enclosed  in  mica  schist,  of  which  they  follow  the  strike  and 
dip ;  but  they  occupy  fissures  which  took  place  along  planes  of 
easy  fracture,  and  being  of  subsequent  origin  to  the  surrounding 
rocks,  are  veins  and  not  beds. 

Natural  Gas.* — Though  the  Chinese  were  before  the  Ameri- 
cans in  their  use  of  natural  gas,  it  is  to  the  United  States  that  we 
must  look  for  examples  of  gas  springs,  which  have  been  so  largely 
turned  to  account  during  the  last  ten  years,  more  especially  in 
Pennsylvania,  but  also  in  Ohio  and  New  York. 

According  to  the  late  Mr.  Ashburner,f  the  gas  in  these  States 
comes  from  beds  of  Palaeozoic  sandstone  and  limestone.  He 
considers,  with  many  others,  that  both  gas  and  petroleum 
have  been  formed  by  the  decomposition  of  animal  and  vegetable 
remains  in  the  rocks,  and  that  in  order  to  have  a  productive  gas 
region,  it  is  necessary  that  there  should  be  a  porous  or  cavernous 
rock  to  contain  the  gas,  and  an  impermeable  covering,  such  as 
shale,  to  prevent  its  escape,  conditions  resembling  those  required 
for  artesian  wells.  A  further  condition  is  that  the  strata  should 
be  bent  into  a  dome,  anticlinal  or  arch,  at  the  crown  of  which 
the  gas  will  be  found  ;  but  if  the  rocks  have  been  much  disturbed, 
contorted,  and  fissured,  natural  vents  have  been  formed,  through 
which  the  gas  will  have  escaped.  The  rocks  now  containing  the 
gas  are  often  those  in  which  it  was  generated. 

There  are  several  gas-producing  beds  of  sandstone  in  Pennsyl- 
vania, in  the  Carboniferous  rocks ;  but  the  most  important  supplies 
are  obtained  from  sands  of  the  Venango- Butler  oil-group,  belong- 
ing to  the  Catskill  Rocks  of  the  Devonian  period.  There  are 
other  gas-sands  in  the  Chemung  and  Portage  rocks,  also  of  the 
Devonian  Period,  but  lower  down.  Some  of  them  produce  both 
gas  and  oil. 

The  most  productive  gas-bearing  rocks  in  Ohio  are  the  Berea 
grit  in  the  Sub-carboniferous  period,  and  the  Trenton  Limestone 
in  the  Lower  Silurian  period. 

The  section  (Fig.  48)4  shows  the  Silurian  and  Devonian  strata 
bent  into  an  arch  or  dome  at  Findlay,  Ohio,  where  gas  and  petro- 
leum are  obtained  by  boring  into  the  Trenton  Limestone,  the 
reservoir  in  which  they  are  confined  by  the  Utica  Shale. 

The  gas  varies  in  composition,  not  only  from  well  to  well,  but 
also  from  time  to  time  in  the  same  well.  Some  analyses  given  by 
Prof.  Lesley  show  that  the  gas  of  a  certain  well  contained  upon 

*  Topley,  "  The  Sources  of  Petroleum  and  Natural  Gas,"  Jour.  Soc.  Arts, 
vol.  xxxix.  (1891),  p.  421. 

t  "  The  Geologic  Distribution  of  Natural  Gas  in  the  United  States," 
Trawt.  Amer.  lust.  M.E.,  vol.  xv.  (1886-87),  P-  505. 

£  Topley,  Op.  cit.  p.  413. 


6o 


ORE  AND  STONE-MINING. 


FIG.  48. 
SECTION  THKOUGH  FINDLAY,  OHIO.     (Orton.) 


X-X   Sea  Laud 


^         •       (7-    Ohio  shale. 
1 


Silurian 


1 6.    Upper  Helderberg  limestone. 
5.    Lower  Helderberg  limestone. 

( Niagara  limestone.  ' 
4.  \  Niagara  shale. 

(Clinton  limestone. 

j  Hudson  Kiver  shale. 
3>  I  Medina  shale. 


Utica  shale. 
Trenton  limestone. 


different  occasions  from  50  to  75  per  cent,  of  marsh  gas,  9  to  35 
per  cent,  of  hydrogen,  4  to  1 2  per  cent,  of  ethylic  hydride  with 
small  quantities  of  olefiant  gas,  oxygen,  carbonic  oxide  and 
carbonic  acid,  and  in  one  instance  as  much  as  23  per  cent,  of 
nitrogen,  though  usually  this  gas  was  absent.  The  pressure  of 

the  escaping  gas  is  often  very 
great,  and  in  one  case  reached 
450  Ib.  per  square  inch. 

Nickel.  —  Until  recently 
our  supplies  of  this  metal 
were  obtained  from  sulphides 
or  sulpharsenides,  and  espe- 
cially from  nickel-bearing 
pyrrhotine.  The  discovery 
by  Gamier  of  hydrated  sili- 
cate of  nickel  and  magnesium 
in  New  Caledonia  revealed 
the  existence  of  an  unsuspected  source  of  wealth.  The  nickel  is 
found  in  serpentine,*  either  at  the  contact  of  this  rock  with 
" pockets"  of  red  clay,  or  near  such  a  contact,  but  never  in  the 
clay  itself. 

*  Levat,  "Memoire  sur  les  progres  de  la  metallurgie  du  Nickel,"  A nn. 
Mines,  96  fcerie,  vol.  i.  (1892)  p.  141. 


|  Nickel  ore. 
[•-•••?;ffl:*ff|  Oolitic  broicn  iron  ore. 
S      Serpentine. 
A     Red  Clay. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


61 


FIG.  50. 


Figs.  49,  50,  and  51  are  examples  of  various  types  of  such 
deposits.  In  all  three  cases  A  is  the  pocket  of  red  clay,  and  S  is 
the  serpentine.  In  Fig.  49 
the  nickel  ore  lies  between 
the  rock  and  the  clay.  In 
Fig.  50  there  are  a  number 
of  interlacing  veins  in  the 
serpentine  forming  a  net- 
work deposit  which  is  quar- 
ried, whilst  in  the  case  re- 
presented by  the  Fig.  51, 
the  original  fissures  were 
bigger,  but  less  numerous, 
and  are  now  filled  up  with 
nickel  ores  forming  veins 
20  to  26  feet  in  width.  The  ferruginous  red  clay  often  contains 
the  hydrated  oxides  of  manganese  and  cobalt,  besides  chromic  iron 
(Fig.  19).  Large  lumps  of 

limonite  are  frequently  FIG.  51. 

found  lying  upon  the 
clay,  Fig.  49.  The  ore 
which  is  exported  has 
from  7  to  1  8  per  cent,  of 
nickel. 

Of  still  later  date  are 
the  discoveries  of  nickel 
ore  at  Sudbury*  on  the 

Canadian  Pacific  Railway,  about  40  miles  north  of  Georgian  Bay. 
Here   the   ore   is   a   nickel  -bearing  pyrrhotine    associated   with 

FIG.  52. 


a,  Huronian  strata  ;  6,  diorite  ;  c,  ore-body  ;  s,  shaft  ;  x  x,  boreholes. 

chalcopyrite.     These  two  minerals  form  large  ore  bodies  (Figs. 
52  and  53)  in  or  near  a  belt  of  diorite  in  a  district  occupied 

*  Collins,  "On  the  Sudbury  Copper  Deposits,"  Q.  J.  G.  S.,  vol.  xliv. 
(1888),  p.  834,  from  which  paper  the  two  figures  are  borrowed.  Snelus 
.and  Colquhoun  in  the  special  volume  of  Proceedings,  The  Iron  and  Steel 
Institute  in  America  in  1890,  pp.  213,  359. 


62 


ORE  AND  STONE-MINING. 


by  rocks  belonging  to  the  Huronian  and  Laurentian  systems. 
The  shape  of  the  ore  bodies  is  very  irregular,  but  their  size  is 
great ;  some  are  hundreds  of  feet  long,  by  a  hundred  or  more 
feet  in  breadth.  The  two  minerals  are  worked  and  treated 

FIG.  53- 


FIG.  54. 


a,  Huronian  rocks  ;  b,  diorite  ;  c,  ore-mass ;  s,  shaft  on  diagonal  vein. 

together,  for  picking  by  hand  has  been  found  to  be  impracticable 
on  a  commercial  scale,  and  separation  by  the  ordinary  washing 
process  is  impossible,  owing  to  the  small  difference  between  their 
specific  gravities. 

Ore  of  good  average  quality  contains  4  per  cent,  of  nickel. 
Nitrate  of  Soda. — The  existence  of  beds  of  nitrate  of  soda, 
cubic  nitre,  in  the  rainless  regions  on  the  West  Coast  of  South 

America  had  been  noticed  in 
books  on  mineralogy  for  many 
years  ;  but  it  was  not  till  this 
mineral  was  found  to  be  a  valu- 
able fertiliser  that  steps  were 
taken  to  work  it  on  a  large 
scale. 

The  raw  nitrate  of  soda 
(caliche)  is  found  in  beds  from 
6  inches  to  12  feet  thick,  be- 
neath a  covering  of  hard  con- 
glomerate (costra)  from  i  to  10 
feet  thick,  as  shown  in  Fig. 
54.*  It  is  supposed  that  it 
been  formed  by  the  action 


a,  soft  earth ;  &,  "  caliche  "  ;  c,  con- 


glomerate ;  d,  sand  ;  e,  charge  of  gun- 
powder ;  /,  tamping  ;  g,  safety-fuse. 

of  animal  and  vegetable 
matter  upon  salt  left  by  the  evaporation  of  sea- water,  and  this 
theory  is  supported  by  the  fact  that  guano  and  the  remains  of 

*  Harvey,  "  Machinery  for  the  Manufacture  of  Nitrate  of  Soda  at  the 
Ramirez  Factory,  Northern  Chili,"  Proc.  Inst.  C.E.,  vol.  Ixxxii.  (Session 
1884-85),  P-  337- 


MODE  OF  OCCURRENCE  OF  MINERALS.          63 

birds  and  fish  are  found  close  to  the  caliche,  and  also  by  the 
presence  of  iodine,  an  element  pertaining  to  the  sea,  in  the  form 
of  iodides  and  iodates. 

Another  theory,  that  of  Dr.  Carl  Ochsenius,*  is  that  salt  lakes 
were  formed  by  the  elevation  of  a  barrier  which  shut  out  the  sea, 
that  these  gradually  evaporated,  that  carbonic  acid  due  to 
volcanic  agencies  converted  some  of  the  chloride  of  sodium  into 
carbonate,  and  that  finally  guano  dust,  wafted  by  the  prevailing 
breeze  from  guano  islands  near  the  coast,  brought  nitrogenous 
matter,  which  eventually  became  oxidised  and  converted  the 
carbonate  into  nitrate. 

An  analysis  of  caliche  given  by  Mr.  Harvey  is  as  follows  : — 


Nitrate  of  soda    . 
Common  salt 
Sulphate  of  soda  . 
Sulphate  of  magnesia 
Insoluble  matter  . 


Per  cent. 


This  sample  was  richer  than  the  average  ;  for  the  best  caliche 
contains  about  40  to  50  per  cent.,  middle  30  to  40,  and  poor 
caliche  17  to  30  per  cent,  of  nitrate. 

Ozokerite. — The  most  productive  ozokerite  mines  are  found  at 

FIG.  55- 


SCALE. 


1400  MCTRCS 


Boryslaw,  near  Drohobycz,  in  Galicia.  The  mineral  occurs  in  an 
oval  area  some  1,500  yards  long  and  a  quarter  of  a  mile  wide  at 
the  broadest  part,  with  the  long  axis,  AB,  running  in  a  N.W.  and 

*  Eng.  Min.  Journ.,  vol.  xlvi.  (1888),  p.  152. 


64 


ORE  AND  STONE-MINING. 


S.E.  direction,  or  parallel  to  the  trend  of  the  Carpathians*  (Fig.  55). 
The  surrounding  rocks  are  beds  of  sandstone  arid  shale  of  Miocene 
age,  bent  into  a  dome  like  a  dish-cover,  whilst  the  productive 
area  itself  consists  of  the  same  strata  traversed  by  a  main  set  of 

FIG.  56. 


fractures  in  the  direction  AB  (Fig.  55),  and  numerous  cross- 
fractures.  In  this  mass  of  shattered,  crushed,  and  faulted  rock 
the  ozokerite  has  been  deposited  ;  it  fills  every  crack  and  crevice 
into  which  it  could  penetrate,  sometimes  crossing  the  stratification 


Inches  12     6      o 


2  feet 


o        20       40       60  •     So       too  centimetres. 

and  sometimes  following  the  planes  of  bedding  for  some  distance, 
and  then  breaking  across  in  an  irregular  manner  (AB,  Fig.  57). 
The  veins  vary  in  thickness  from  a  mere  knife-edge  to  several  feet. 
Fig.  56  is  a  diagrammatic  section  along  the  line  CD  (Fig  55), 
and  is  intended  to  convey  some  idea  of  the  jumble  of  rocks  between 
E  and  F,  the  centre  part  from  G  to  H  being  specially  cracked, 
squeezed,  and  faulted.  The  richest  mines  are  those  sunk  in  the 
deeply-shaded  part  of  the  plan,  corresponding  to  GH  of  the 
section.  Petroleum  is  found  in  the  rocks  within  the  ozokerite 
area  and  also  in  those  surrounding  it  for  a  certain  distance,  but 
there  is  less  on  the  north  side  than  on  the  south. 

*  For  much  of  the  information  concerning  Boryslaw,  I  am  indebted  to 
explanations  given  to  me  on  the  spot  by  Mr.  A.  Platz,  manager  of  the 
largest  mine. 


MODE  OF  OCCURRENCE  OF  MINERALS.          65 

Petroleum. — The  conditions  under  which  rock-oil  is  found 
in  the  earth's  crust  are  precisely  the  same  as  those  described  in 
speaking  of  natural  gas,  viz.,  a  porous  bed  for  storing  the 
mineral,  an  impermeable  bed  for  preventing  its  escape,  and 
very  often  an  anticlinal  arrangement  of  the  strata,  though  this  is 
of  less  importance  than  in  the  case  of  gas. 

The  three  great  oil  regions  of  the  world  at  present  are 
Baku,  Burmah,  and  Pennsylvania.  I  put  Baku  first,  because 
the  existence  of  the  eternal  fires  of  the  Apsheron  Peninsula 
on  the  Caspian  Sea  has  been  known  for  about  2,500  years, 
and  because  some  of  its  wells  have  surpassed  in  productiveness 
anything  met  with  elsewhere.  The  principal  wells  are  in  the 

FIG.  58. 


Balakhani-Saboontshi  district,  some  eight  miles  North  of  Baku, 
and  at  Bibi-Eibet,  a  little  to  the  south.  The  rocks  are  of  Lower 
Miocene  age,*  and  consist  of  sand,  calcareous  clays,  marls,  and  in 
places  compact  sandstone.  The  sectionf  (Fig.  58,  after  Abich) 
shows  the  wells  on  the  crown  of  a  low  anticlinal.  The  petroleum 
is  found  in  three  well-defined  beds  of  sand  ;  these  sands  are  in  a 
semi-fluid  condition  and  contain  salt  water  in  addition  to  petroleum 
and  carburetted  hydrogen  gas.  Sometimes  the  pressure  of  the 
gas  amounts  to  300  Ibs.  per  square  inch. 

At  some  of  the  wells  it  is  necessary  to  pump  up  the  petroleum, 
but  at  others  it  rises  naturally  and  occasionally  with  great  force 
and  in  immense  quantities.  In  fact,  Tagieff's  spouterj  in  1886 
actually  threw  up,  on  the  eighth  day  after  oil  had  been  struck, 
the  immense  quantity  of  n,ooo  tons  or  2J  millions  of  gallons  in 
twenty-four  hours.  The  flow  then  diminished  and  was  got  under 
control  by  the  engineers,  and  reduced  to  a  quarter  of  a  million 
gallons  a  day.  Fig.  59,  copied  from  a  photograph,§  represents  a 
spouting  well  at  Baku. 

The  principal  oil-fields  of  Burmah  ||  are  situated  near  the 
villages  of  Twingoung  and  Berne,  about  a  mile  and  a  half  east  of 
Yenangyaung  on  the  Irrawaddy,  and  130  miles  south  of 
Mandalay.  The  rocks  belong  to  the  Tertiary  period  and  are 
probably  of  Miocene  age,  the  prevailing  strata  being  clayey  sands 

*  Vasilieff,  "The  Oil  Wells  of  Baku,"  Proc.  Inst.  C.E.,  vol.  Ixxxiii. 
(1885-6),  p.  406. 

t  Topley,  Op.  tit.,  p.  429. 

i  Marvin,  The  Coming  Deluge  of  Russian  Petroleum.     London,  1886,  p.  9. 

§  Lent  to  me  by  Mr.  Boverton  Redwood. 

||  F.  Noetling,  "  Keport  on  the  Oil  Fields  of  Twingoung  and  Berne, 
Burma,"  Records  of  Geol.  Survey  of  India,  vol.  xxii.  (1889),  p.  75. 


66 


ORE  AND  STONE-MINING. 


and  soft  sandstone.  The  petroleum  is  found  in  beds  of  soft  sand- 
stone, which,  together  with  partings  of  blue  clay,  have  been  proved 
to  be  200  feet  thick,  and  are  probably  very  much  more.  The  sand- 
stone is  soaked  with  petroleum,  which  oozes  gradually  into  the  wells, 
but  certain  layers  are  richer  in  petroleum  than  others.  The 
lower  strata  of  the  formation  are  more  productive  than  the  upper- 
ones.  The  oil-bearing  rocks  are  overlain  by  thick  beds  of  blue 

FIG.  59. 


clay  which  prevent  the  petroleum  from  rising.  The  greatest  depth 
reached  by  a  Burmese  well  is  310  feet.  Noetling  thinks  that  the 
oil  was  produced  in  the  sandstone  formation  in  which  it  is  now 
found,  though  perhaps  not  in  the  uppermost  beds. 

At  present  there  are  no  flowing  wells,  but  these  might  be  obtained 
if  the  oil-bearing  strata  were  tapped  at  a  greater  depth,  for  then 
the  gas  which  accompanies  the  petroleum  would  be  under  greater 
pressure.  Where  beds  lie  as  shallow  as  they  do  at  the  existing 
workings,  the  gas  has  already  drained  off  to  a  great  extent  through 
cracks  in  the  strata.  The  highest  daily  yield  of  a  single  well  was 
500  viss,*  but  many  of  what  can  be  called  fairly  rich  wells  pro- 
duced upwards  of  100  viss  a  day.  The  yield  decreases  rapidly 
during  the  first  two  years  to  the  extent  of  at  least  25  per  cent., 
and  after  ten  or  fifteen  years  a  well  does  not  produce  more  than 
5  per  cent,  of  what  it  did  at  first.  The  total  daily  production  of 
the  two  fields  ranges  from  15,000  to  20,000  viss  per  day. 

*  i  ^$  =  3-0857  Ibs. 


MODE  OF  OCCURRENCE  OF  MINERALS.          67 

The  year  1859  marks  the  first  discovery  of  petroleum  on  a 
commercial  scale  in  the  United  States,  though  the  oil  had  been 
known  as  long  ago  as  1627. 

The  strata  which  yield  oil  in  Pennsylvania  and  New  York 
belong  to  the  Devonian  and  Carboniferous  periods.  They  are 
beds  of  sand  and  sandstone,  sometimes  coarse-grained,  and  are 
the  same  as  those  producing  gas  ;  in  fact  a  well  may  often  produce 
both  gas  and  petroleum,  or  first  gas  and  then  a  little  oil.  In 
Ohio  the  two  chief  sources  of  oil  are  the  Trenton  Limestone 
[Lower  Silurian]  and  the  Berea  Grit  near  the  base  of  the 
Carboniferous  rocks.* 

Phosphate  of  Lime. — The  trade  in  this  fertiliser  is  very 
large,  and  fortunately  the  sources  of  supply  are  numerous. 
Deposits  of  phosphate  of  lime  are  found  in  rocks  of  all  ages,  from 
the  Laurentian  to  the  recent  period.  I  may  mention  specially 
apatite  from  Canada,  and  various  kinds  of  phosphate  from  the 
Cretaceous  rocks  in  Europe,  from  South  Carolina,  Florida,  and 
the  West  Indies. 

The  Laurentian  rocks  are  the  home  of  the  apatite  in  Canada. 
The  principal  mines  are  in  the  county  of  Ottawa  (Q.),  and  the 
mineral  occurs  mainly  in  pyroxenite,  sometimes  as  a  contem- 
poraneous bed  and  sometimes  as  a  vein  of  posterior  origin. 

The  beds  are  from  i  foot  to  3  or  4  feet  thick,  and  the  veins  from 
a  few  inches  to  8  or  10  feet  wide. 

Though  worked  to  some  extent  in  Bedfordshire,  Buckingham- 
shire, and  Cambridgeshire,  the  Cretaceous  rocks  have  of  late 
years  yielded  far  more  abundant  supplies  of  phosphate  in  France 
than  in  England.  In  the  mining  district  of  Arrasf  deposits  of 
phosphate  of  lime  are  worked  in  three  horizons :  (i)  At  the  base 
of  the  Gault,  in  the  form  of  a  bed  of  nodules,  generally  about  2 
inches  thick,  and  sometimes  as  much  as  6  inches  thick ;  (2)  above 
the  Gault,  in  the  form  of  beds  of  nodules,  6  inches  (15  cm.)  to 
3  feet  3  inches  (i  m.)  thick ;  (3)  in  the  state  of  sand,  in  more  or 
less  regular  pockets,  in  the  upper  beds  of  the  Chalk.  This  sandy 
phosphate  is  covered  by  a  bed  of  clay  with  flints,  above  which 
comes  brick-earth  (Fig.  60).  The  sides  of  the  pockets  are  formed 
by  the  chalk  with  Micraster  cor-anguinum,  or  "  Santonien " ; 
whilst  the  fossils  in  the  pockets  belong  to  the  base  of  the 
"  Senonien,"  or  chalk  with  Belemnites  quadratus.  The  pockets 
are  generally  contiguous  to  each  other,  but  vary  a  good  deal 
in  depth  up  to  65  feet  (20  m.)  The  phosphatic  deposit  is  a 

*  Ashburner,  Op.  cit.  Topley,  Op.  cit.  Weeks,  "  Petroleum,"  Mineral 
Resources  of  the  United  States,  Calendar  Year  1886.  Washington,  1887, 
p.  458  ;  and  Calendar  Years  1889  and  1890,  p.  287. 

f  Statist  ique  de  V  Industrie  Miner  ale  et  des  appareils  a  vapeur  en  France 
.et  en  Alf/erie  pour  Pannee  1886.  Paris,  1888,  p.  243.  Figure  60  is  taken 
from  my  own  notes,  and  differs  slightly  from  the  one  given  in  the  official 
volume. 


68 


ORE  AND  STONE-MINING. 


very  fine  yellowish  and  occasionally  white  sand,  which  under  the 
microscope  is  found  to  consist  of  transparent  concretionary  grains, 


FIG.  60. 


FIG.  61. 


A,  chalk  ;  B,  phosphatic  chalk  ;  C,  sandy  phosphate  of  lime  ; 
D,  clay  with  flints  ;  E,  brick-earth  ;  F,  soil. 

made  up  of  concentric  layers  ;  its  average  thickness  may  be  taken 
at  3  feet  4  inches  (r  m.)     The  chalk  adjacent  to  the  pockets  is 

often  phosphatic.  M.  Merle  and 
other  geologists  think  that  the 
phosphate  is  derived  from  the 
lixiviation  in  situ  of  the  chalk 
with  belemnites  by  rain  water 
containing  carbonic  acid. 

The    famous    beds    of     South 
A    Carolina,*  besides  satisfying  to  a 
_  ____        great   extent   the   wants    of   the 
SCALES  United  States,  are  able  to  supply 

•    •    7   ?   ?   1.°  v   '.*FEET  large   quantities  of  the  fertiliser 
«'  ?  METRES    to  other   countries.      They   were 

^J^  in  .I$67,  '  and,  owing  to 
*he  facility  with  which  they  can 
be  worked  and  their  proximity 
to  a  seaport,  the  trade  has  in- 
creased very  rapidly.  The  mineral  occurs  in  the  form  of 
nodules,  from  the  size  of  a  pea  to  that  of  a  man's  head,  in  a 
bed  from  a  few  inches  to  2<|  feet  thick,  the  average  thickness  being 
7  to  9  inches  (Fig.  61).  With  the  nodules  are  found  bones  of  fish 
and  especially  teeth  of  great  sharks,  together  with  teeth  of  the 


A,  Ashley  marl  (Eocene)  ;  B,  bed 
of  phosphatic  nodules  ;  C,  ferru- 
ginous  sand  ;  D,  clayey  sand. 


*  E.  A.  F.  Penrose,  "  Nature  and  Origin  of  Deposits  of  Phosphate  of 
Lime,"  Bulletin  of  the  U.S.  Geol.  Survey,  No.  46.    Washington,  1888,  p.  63. 


MODE  OF  OCCURRENCE  OF  MINERALS.         69 

horse  and  other  land  animals.  The  deposit  is  considered  to  be  of 
Post-Pliocene  age. 

The  existence  of  valuable  deposits  of  phosphate  in  Florida* 
was  not  known  till  1887.  There  are  four  different  kinds 
of  the  fertiliser  —  (i)  "hard  rock"  phosphate,  (2)  "soft" 
phosphate,  (3)  "land  pebble"  phosphate,  (4)  "river  pebble" 
phosphate. 

The  "hard  rock"  is  a  hard,  massive,  light  grey  phosphate  of 
lime,  with  cavities  lined  with  secondary  mammillary  incrustations 
of  the  mineral.  It  has  been  produced  by  the  alteration  of 
Eocene  and  Miocene  limestone,  and  yields  about  36  or  37  per 
cent,  of  phosphoric  anhydride  (P205). 

The  "soft"  phosphate  includes  material  resulting  from  the 
disintegration  of  the  hard  phosphate,  and  also  highly  phosphatic 
sands  and  clays,  rarely  averaging  more  than  22  per  cent,  of  phos- 
phoric anhydride. 

The  "  land  pebble ''  phosphate  is  made  up  of  pebbles  of  various 
sizes,  up  to  that  of  a  walnut.  They  consist  of  an  earthy  material 
carrying  pisolitic  grains  of  phosphate  of  lime,  or  of  a  substance 
resembling  the  hard  rock  phosphate.  The  percentage  of  phos- 
phoric anhydride  is  about  32. 

The  "river  pebble"  phosphate  is  found  in  the  beds  of  the 
present  rivers,  and  also  in  their  ancient  channels.  The  pebbles 
are  blue,  black,  and  grey  in  colour,  and  contain  the  bones  and 
teeth  of  various  animals.  They  yield  from  20  to  28  per  cent,  of 
phosphoric  anhydride. 

The  phosphate  of  lime  worked  at  Aruba  and  Sombrero,  in  the 
West  Indies,  was  originally  a  coral  limestone ;  its  conversion 
into  phosphate  has  been  effected  by  the  percolation  of  water 
containing  phosphoric  acid  derived  from  the  dung  of  sea-fowl. 
This  interesting  fact  is  made  very  plain  by  finding  corals 
themselves  changed  into  phosphate  of  lime.  In  the  island  of 
Redonda,  owing  to  a  difference  in  the  rocks  acted  on  by  the 
drainage  from  the  excrement,  the  mineral  produced  is  phosphate 
of  alumina. 

Potassium  Salts. — The  deposits  of  various  potassium  salts  at 
Stassfurt  belong  to  the  Bunter  Sandstone  formation  of  the 
Magdeburg-Halberstadt  basin,  and  workings  have  now  shown 
that  they  attain  a  thickness  of  very  nearly  3000  feet  (900 
metres). 

The  beds  may  be  divided  according  to  their  chemical  com- 
position into  four  regions,f  which  in  descending  order  are  : — 

*  Eldridge,  "A  Preliminary  Sketch  of  the  Phosphates  of  Florida," 
Trans.  Amer.  Inst.  M.E.,  vol.  xxi.  (1892),  p.  196.  Wyatt,  The  Phosphates 
of  America.  New  York,  1891. 

t  Fiihrer  zum  vierten  Bergmannstag,  1889.  Halle  a.  d.  Saale,  1889,  p. 
xxxiv. 


7° 


ORE  AND  STONE-MINING. 


APPROXIMATE  THICKNESS. 
Feet.        Metres. 


4.  Carnallite  region. — Carnallite  is  the  double 
chloride  of  potassium  and  magnesium 
(KC1,  MgCl,  +  6H2O) 82 

3.  Kieserite  region. — Kock  salt  with  beds  of 

kieserite  (MgSO4  +  H2O)  .  .  .  .183 

2.  Polyhalite  region. — Rock  salt  with  strings  of 

polyhalite  (KjSO,,  MgS04,  2CaS04,  +  2H2O)  197 

i.  Rocksalt. — An  exceedingly  thick  bed. 


25 
56 
60 


As  is  shown  by  the  section  (Fig.  62),  the  edge  of  the  carnallite 
region  consists  of  kainite  (K2S04,  MgS04,  MgCl,  +  6H9O) ;  this 


w.s.w. 
I 


FIG.  62. 

Xudwiy  ff  Skaff_ 


a,  Older  rock  salt ;  &,  polyhalite  region  ;  c,  kieserite  region  ; 
fZ,  carnallite  ;  e,  saliferous  clay  ;  /,  kainite  ;  g,  sylvinite  ;  h,  gyp- 
sum and  anhydrite  ;  i,  younger  rock  salt ;  j,  gypsum  ;  7j,  /,;  varie- 
gated marls  with  thin  beds  of  limestone  and  of  oolite  ;  I,  diluvium 
and  alluvium.  The  depths  marked  are  in  metres. 

is  considered  to  be  of  secondary  origin,  and  so  also  is  regarded 
the  sylvinite,  a  mixture  of  potassium  and  sodium  chlorides  with 
their  sulphates,  which  occurs  in  workable  quantities. 

Above  the  potassium  salts  is  a  bed  of  saliferous  clay  26  feet  (8  m.) 
thick,  and  then  290  feet  (90  m.)  of  anhydrite,  which  forms  the  floor 
of  the  Bunter  beds.  At  several  places  there  is  a  younger  bed 
of  rock-salt  from  130  to  400  feet  (40  to  120  m.)  thick. 

Rock-salt  is  worked  to  a  small  extent,  but  the  potassium  salts, 


MODE  OF  OCCURRENCE  OF  MINERALS. 


especially  carnallite  and  kainite.  are  the  main  objects  of  the 
mining.* 

Quicksilver. — The  principal  quicksilver  producing  mines  at 
the  present  time  are  Almaden,  in  Spain,  Idria,  in  Carniola,  and 
New  Almaden,  in  California.  There  are  also  several  other  mines 
in  California,  and  workings  of  some  importance  in  Russia  and 
Italy.  Peru  was  at  one  time  remarkable  for  its  quicksilver 
deposits  at  Huancavelica,  but  these  are  no  longer  worked.  China 
possesses  some  little-known  mines  in  the  province  of  Kwei-Chau. 

The  relative  importance  to  the  world  of  the  principal  deposits 
is  shown  by  the  following  table,  taken  from  Mr.  Becker's  mono- 
graph, t 

PRODUCT  OF  THE  PRINCIPAL  DISTRICTS,  IN  SPANISH  FLASKS  OP 
75  SPANISH  POUNDS,  OR  34*507  KILOGRAMMES. 


|| 

Up  to 
1700. 

1700  to 
1800. 

1800  to 
1850. 

1850  to 

1886. 

Total  to 
Jan.  1886. 

Aliiiadcu     .     . 
Idria.     .     .     . 
Huancarelica  . 
California  .     . 

Year 

1564 
1525 
i57i 
1850 

517,684 
399,861 
881,867 

1,221,477 
608,743 
543.642 

1,091,075 
242,226 
75.604 

1.135.576 

3°!.  549 
1,429,346 

3,965,812 

1.552,379 
1,501,113 
1,429,346 

1,799,412 

2,373.862 

1,408,905 

2,866,471 

8,448,650 

Mr.  Becker  has  brought  together  a  vast  array  of  useful  facts 
concerning  the  occurrence  of  quicksilver  in  his  valuable  mono- 
graph, which  may  be  very  briefly  summed  up  as  follows : — J 
Cinnabar  is  found  in  rocks  of  all  ages  and  of  all  descriptions, 
viz.,  conglomerate,  sandstone,  quartzite,  limestone,  shale, 
slate,  serpentine,  crystalline  schist,  and  basic  and  acidic 
volcanic  rocks,  but  it  exhibits  a  preference  for  sand- 
stone. The  quicksilver  deposits  are  found  along  lines  of  country 
marked  by  past  or  present  volcanic  disturbances.  This  fact  is 
made  very  plain  by  a  map  of  the  world  on  which  are  indicated 
all  important  occurrences  of  the  metal.§ 

Some  cinnabar  has  certainly  been  precipitated  from  hot  solutions 
brought  up  by  volcanic  springs,  and  it  seems  likely  that  many 
of  the  quicksilver  deposits  have  been  formed  in  this  manner.|| 

The  cinnabar  is  often  found  filling  up  interstitial  spaces  of 
the  rock,  and  if  the  rock  is  sedimentary  it  sometimes  cuts  across 
the  planes  of  stratification,  and  sometimes  runs  parallel  to  them. 

*  Precht,  Die  Safe-Industrie  von  Stassfurt  und  Umgeyend.  4th  edition, 
Stassfurt,  1889. 

t  Becker,  "  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope," 
Monographs  of  U.  8.  Geol.  Survey,  vol.  xiii.  Washington,  1888,  p.  7. 

$  Ibid.  p.  50.  §  Ibid.  p.  15.  ||  Ibid.  p.  55. 


72  ORE  AND  STONE-MINING. 

Spain. — The  famous  and  productive  Almaden  mine  is  situated 
on  the  northern  slope  of  the  Sierra  Morena,  where  the  rocks 
coming  up  to  the  surface  are  of  Silurian  and  Devonian  age. 
These  rocks  are  beds  of  sandstone  and  quartzite  interstratified 
with  slate  and  a  little  limestone.  The  cinnabar  occurs  impregnat- 
ing the  sandstone ;  the  slate  is  rarely,  if  ever,  quicksilver-bearing. 
There  are  three  principal  deposits  extending  for  a  distance  of  200 
to  220  yards  (180  to  200  m.)  along  the  strike,  the  dip  is  almost 
vertical.  The  total  useful  thickness  of  the  three  beds  is  reckoned 
to  be  40  feet  (12  m.),  and  the  mercurial  rock  yields  on  an  average 
10  per  cent,  of  metal.  It  seems  probable  that  these  sandstone 
beds  were  impregnated  by  aqueous  solutions  which  came  up  from 
below.  They  may  be  called  veins  or  beds  according  to  the  defini- 
tions one  chooses  to  adopt  for  a  vein.  No  doubt  the  cinnabar  is 
of  subsequent  origin  to  the  main  part  of  the  stratum ;  but  the 
same  may  be  said  for  the  copper  in  the  conglomerate  beds  of  Lake 
Superior,  and  possibly  for  the  gold  in  the  "  banket "  of  South 
Africa.  The  quicksilver  solutions  deposited  their  metal  in 
cavities  existing  between  the  particles  composing  the  sand- 
stone, and  I  think  in  a  case  of  this  kind,  where  more  than 
90  per  cent,  of  the  deposit  is  matter  of  detrital  origin,  it  is  most 
convenient  to  speak  of  the  deposits  as  beds.  However,  in  two  of 
the  mercurial  strata  there  are  little  strings  arid  seams,  either 
parallel  to  the  bedding  or  crossing  the  planes  of  stratification  in  all 
directions.  Looked  at  on  a  small  scale,  these  strings  could  be 
called  veins,  but  when  one  has  to  deal  with  the  workable  stratum 
as  a  whole  it  may  be  called  a  bed. 

Austria. — At  Idria,  in  Carniola,*  cinnabar  occurs  in  theTriassic 

FIG.  63. 


A,  compact  sandstone  ;  B,  less  compact  sandstone  impregnated 
with  cinnabar  13  to  16  feet  (4  to  5  m.)  thick ;  C,  shale  ;  D,  thinly- 
bedded  sandstone. 

rocks  in  three  ways  :  (i)  impregnating  beds  of  shale,  conglomerate 
and  dolomitic  breccia  ;  (2)  filling  up  of  cracks  like  ordinary  fissure 
veins  ;  (3)  in  irregular  veins  across  the  mass,  making  a  stock- 
work.  Lipold  supposes  that  it  was  introduced  by  watery  solu- 
tions in  late  Tertiary  times. 

*  Das  k.  7b.  Quecksilberiverk  zu  Idria  in  Krain.     Vienna,  1881. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


73 


Russia. — An  interesting  and  important  deposit  is  being  worked 
at  Ekaterinoslav  in  Southern  Russia,  a  section  of  which  is  given 
in  Fig.  63.  The  cinnabar  is  disseminated  through  a  sandstone, 
which  lies  between  another  bed  of  sandstone  of  a  more  compact 
nature  and  a  bed  of  shale.  Once  more  we  have  a  case  in  which 
the  mercurial  solutions  made  their  way  upwards  along  the  easiest 
channels  they  could  find. 

California. — The  quicksilver  deposits  of  California*  are  found 
in  various  parts  of  the  State,  from  the  extreme  north  to  Los 
Angeles.  The  most  important  mine  is  New  Almaden,  situated 
about  fifty  miles  to  the  S.E.  of  San  Francisco. 

In  California,  as  in  Austria,  the  deposits  of  cinnabar  are  of 
several  types,  even  at  one  and  the  same  mine.  Thus,  at  New 


FIG.  64. 


Almaden  the  commonest  kind  of 
ore-body  is  a  network  of  veins  and 
veinlets  through  the  rock,  in  fact  a 
stockwork.  If  the  disturbance  pro- 
duced a  clean  fissure  instead  of  a 
multitude  of  irregular  cracks,  then 
the  single  rent  was  filled  up  and 
produced  what  some  would  call  a 
typical  vein.  Lastly,  if  the  mercu- 
rial solutions  traversed  beds  of  sand- 
stone, they  deposited  some  of  their 
contents  in  the  interstitial  spaces 
between  the  grains,  and  so  formed 
an  ore-bearing  stratum.  All  three 
kinds  of  ore-bodies  were  formed  by 
the  same  process  of  deposition,  the 
difference,  if  I  may  use  the  simile, 
depending  upon  the  lodgings  that 
happened  to  be  vacant,  and  not  upon 
the  lodger  who  came  to  take  up  his 
abode  there,  nor  upon  the  vehicle 
that  brought  him  to  his  new  home. 

The  ore- bodies  at  New  Almaden 

occur  close  to  faults  filled  with  clay  and  fragments  of  rock,  more 
or  less  rounded  by  the  attrition  produced  by  movements  of  the 
"  country."  The  name  given  to  these  faults  by  the  miner  is 
"  altas,"  a  Spanish  term  referring  to  their  usual  position  on  the 
hanging  side  of  the  deposit.  It  seems  as  if  the  impermeable 
clay  had  arrested  and  directed  the  course  of  the  ore-bearing  solu- 
tion as  it  ascended ;  this  is  highly  probable,  and  it  is  an  explana- 
tion which  has  been  offered  in  many  cases  when  the  ores  of  other 
metals  have  been  found  to  "  make  up  against  a  slide." 

The  surrounding  rocks  at  New  Almaden  are  metamorphosed 


Becker,  op.  eit.  p.  317. 


74 


ORE  AND  STONE-MINING. 


sediments  of  Neocomiau  age,  pseud odiorite,  pseudodiabase, 
phthanites,  sandstone,  shale,  and  serpentine.  The  minerals 
accompanying  the  cinnabar  are  iron  pyrites,  marcasite,  quartz, 
calcite,  dolomite,  magnesite,  and  rarely  chalcopyrite. 

The  deposit  worked  at  Great  Western  mine,  70  miles  north  of 
San  Francisco,  is  a  tabular  reticulated  mass  of  rock  (Fig.  64),* 
impregnated  with  cinnabar  and  a  little  native  quicksilver.  It 
lies  between  serpentine  and  a  very  slightly  altered  Neocomian 
sandstone.  The  serpentine  is  accompanied  by  a  belt  of  black 
opaline  rock,  called  the  "  quicksilver  rock  "  by  the  miners.  The 


FIG.  65 


SCALE  OF  FEET. 


longitudinal  section  (Fig.  65)  explains  that  the  ore-bodies  are 
separated  by  spaces  of  barren  ground,  just  as  they  are  in  an 
ordinary  lode. 

The  Sulphur  Bank  mine  is  of  interest  because  the  solfataric 
action,  which  no  doubt  caused  the  deposition  of  the  cinnabar,  is 
still  going  on.  At  first  the  surface  was  worked  for  sulphur, 
which  had  been  formed  by  deposition  from  sulphuretted  hydrogen 
escaping  through  basalt,  just  as  it  does  in  so  many  places  in  the 
other  volcanic  areas.  A  few  yards  below  the  surface,  the  sulphur 
proved  to  be  cinnabar- bearing,  and  lower  down  cinnabar  was 
found  in  large  quantities. 

Cinnabar  has  since  been  worked  from  the  strata  underlying 
the  basalt.  There  are  beds  of  shale  and  sandstone  of  Neocomian 
age,  in  which  the  quicksilver  ore  is  found  as  impregnations  and 
irregular  seams.  The  ore  is  accompanied  by  quartz,  opal,  iron 
pyrites,  calcite,  bitumen,  and  marcasite.  This  last  mineral  con- 
tains small  quantities  of  gold  and  copper.  Hot  springs  are  common 

*  Becker,  op.  cit.  p.  36 


MODE  OF  OCCURRENCE  OF  MINERALS.  75 

in  the  mine,  and  many  of  them  give  off  gases,  viz.,  carbon  dioxide, 
sulphuretted  hydrogen,  marsh  gas,  nitrogen  and  ammonia. 

Nevada, — From  a  scientific  point  of  view,  one  of  the  most  in- 
teresting mineral  deposits  in  the  United  States  is  that  of  Steam- 
boat Springs  in  Nevada,  only  six  miles  from  the  Comstock  lode. 
A  number  of  hot  springs  exist  along  a  series  of  fissures  about  a 
mile  in  length  ;  siliceous  sinter  is  being  deposited  by  them,  and 
there  are  also  mounds  of  sinter  formed  by  springs  that  are  no 
longer  flowing,  or  whose  only  sign  of  activity  consists  in  emana- 
tions of  steam,  sulphuretted  hydrogen,  carbonic  anhydride,  and 
sulphurous  anhydride.  These  solfataric  gases  also  escape  with 
the  water  at  some  of  the  living  springs. 

The  sinter  is  found  on  analysis  to  contain  many  of  the  heavy 
metals,  viz.,  antimony,  arsenic,  cobalt,  copper,  gold,  iron,  lead, 
manganese,  mercury,  silver,  and  zinc,  some  of  them  certainly 
existing  in  the  form  of  sulphides. 

A  sample  of  the  water  taken  from  a  spring  with  a  temperature 
varying  from  167  to  184°  Fahr.  (75  to  84.5°  C.)  was  analysed;  it 
showed  weighable  quantities  of  arsenic  and  antimony,  and  a  trace 
of  mercury  ;  as  it  cooled  it  could  be  seen  to  deposit  the  sulphides 
of  antimony  and  arsenic  together  with  silica. 

In  one  part  of  the  district,  instead  of  sinter,  a  deposit  like  that 
at  Sulphur  Bank,  consisting  of  sulphur  and  cinnabar,  has  been 
formed ;  and  it  has  been  worked  for  the  commercial  extraction  of 
mercury. 

Salt. — Sea  water,  salt  lakes,  brine  springs  and  wells,  sali- 
ferous  marls  and  rock  salt  are  the  sources  of  this  very  important 
mineral. 

The  extraction  of  salt  from  sea-water  is  carried  on  in  Southern 
Europe  and  other  countries,  where  the  heat  of  the  sun  is  sufficient 
to  evaporate  the  water  which  has  been  led  into  shallow  ponds  ;  and 
the  industry  is  fostered  in  many  cases  by  the  traffic  in  salt  being 
a  Government  monopoly. 

In  South  Africa  and  elsewhere  salt  is  obtained  from  "  pans"  or 
shallow  inland  lakes,  which  become  partially  dried  up  in  the  hot 
season. 

Natural  springs  yielding  brine  are  not  uncommon,  and  brine 
wells  are  dug  or  bored  so  as  to  reach  a  salt-bearing  stratum. 

At  Northwich,*  in  Cheshire,  there  are  two  main  beds  of  rock- 
salt,  each  from  84  to  90  feet  thick,  separated  by  a  bed  of  hard  marl 
30  to  33  feet  thick.  All  these  beds  belong  to  the  Keuper 
division  of  the  Triassic  rocks.  The  amount  of  rock-salt  mined  in 
England  is  small,  only  about  one-tenth  of  that  obtained  from 
brine,  which  is  pumped  from  flooded  mines,  and  from  wells  or 
boreholes  penetrating  saliferous  strata. 

*  Dickinson,  "  Report  on  the  Salt  Districts,"  Reports  of  the  Inspectors  of 
Mines  for  the  Year  1881,  p.  55. 


76  ORE  AND  STONE-MINIXG. 

Silver. — All  galena  carries  some  silver,  and  in  very  many  cases 
there  is  enough  to  make  the  extraction  profitable.  Copper  ores 
also  are  frequently  argentiferous  :  the  silver  in  the  Mansfeld 
cupriferous  shale  has  already  been  mentioned,  and  the  ores 
of  the  Butte  district,  Montana,  are  often  rich  in  the  precious 
metal ;  it  is  needless,  however,  to  dwell  upon  this  and  similar 
sources  of  silver,  though  they  are  of  great  commercial  importance. 
Among  well-known  silver  mines  may  be  mentioned  those  of  the 
great  Comstock  Lode  in  Nevada,  the  Eureka  and  Richmond 
mines  in  the  same  State,  Huanchaca  in  Bolivia,  and  Broken  Hill 
in  New  South  Wales. 

Comstock  Lode. — This  remarkable  lode  strikes  about  north  and 
south  and  dips  about  43°  to  the  east.  The  vein,  which  is  usually 
from  20  to  60  feet  thick  and  as  much  as  several  hundred  feet  thick 
in  some  places,  consists  in  the  main  of  crushed  and  decomposed 
portions  of  the  "  country  "  together  with  clay  and  quartz.  The  sur- 
rounding rocks  are  syenite  and  propylite,  according  to  King,*  or 
cliorite  and  diabase,  according  to  Becker.f  The  latter  says  that  the 
so-called  propylite  is  only  a  decomposed  form  of  other  rocks.  The 
silver  is  found  native  and  in  the  form  of  silver  glance,  polybasite, 
stephanite,  and  occasionally  pyrargyrite ;  other  minerals  in  the 
vein  are  quartz,  iron  pyrites,  copper  pyrites,  besides  oxides  of  iron 
and  manganese,  sulphates  of  calcium  and  magnesium  and  car- 
bonates of  magnesium,  calcium,  lead  and  copper.  The  ore -bodies 
are  soft  and  irregular. 

The  heat  of  the  Comstock  lode  is  noteworthy.  In  the  2700 
feet  level  of  the  Yellow  Jacket  mine,  Mr.  Becker  found  the  temper- 
ature of  the  water  to  be  153°  Fahr.  and  that  of  the  air  126°  Fahr., 
whilst  the  water  of  the  Yellow  Jacket  shaft  at  a  depth  of  3065 
feet  had  a  temperature  of  170°  Fahr. 

Eureka-Richmond. — The  nature  of  the  curious  lode  worked  at 
the  Eureka-Richmond  .t  mines  will  be  best  understood  by  reference 
to  Fig.  66  ;  much  of  it  is  a  mass  of  crushed  limestone  of  Cambrian 
age  lying  between  two  faults,  a  main  one  dipping  N.E.  at  an 
angle  of  70°,  and  a  secondary  one  which  is  much  natter. 

The  main  fault  is  a  fissure  filled  with  clay  or  with  decomposed 
rhyolite  and  clay,  varying  from  a  few  inches  to  15  feet  in  width. 
It  shifts  the  rocks  many  hundreds  of  feet,  and  at  Eureka  the 
throw  exceeds  1400  feet.  The  valuable  parts  of  the  lode  are  ore- 
bodies  of  every  possible  shape  and  size,  some  measuring  upwards 
of  100  feet  in  all  directions.  Above  the  water  level,  or  horizon 
of  decomposition  by  atmospheric  agencies,  the  minerals  constitut- 

*  King  and  Hague,  "  Mining  Industry,"  U.  S.  Geol.  Exploration  of  the 
Fortieth  Parallel.  Washington,  1870. 

t  "  Geology  of  the  Comstock  Lode  and  Washoe  District,"  Monograph 
111.  of  U.  8.  Geol.  Survey.  Washington,  1882. 

£  Curtis,  "The  Silver-lead  Deposits  of  Eureka,  Nevada,"  Monogranh 
VIII.  of  U.  S.  Geol.  Survey.  Washington,  1884. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


77 


ing  the  ore-bodies,  are  galena,  cerussite,  mimetite,  wulfenite, 
with  very  little  quartz  and  calcite,  the  remainder  of  the  veinstuff 
being  mainly  hydrated  oxide  of  iron  carrying  silver  and  gold, 
with  some  carbonate  and  silicate  of  zinc.  Below  the  water  level 
the  minerals  are  pyrites,  arsenical  pyrites,  galena,  blende  and  a 
few  other  sulphides,  besides  silver  and  gold.  One  of  the  char- 

FIG.  66. 


FTioo    o 


SCALE  OF  FEET 
200       400        600       800 


1000 


100 


METRIC   SCALE 
0  100 


200  M. 


H.  Ore. 

G.  Hamburg  Limestone. 

F.  Secret  Canon  Shale. 

E.  Stratified  Limestone. 

D.  Limestone. 

C.  Shale. 


(Prospect  Mountain  Limestone. 
^ 
A.  Prospect  Mountain  Quartzite. 


acteristics  of  the  ore  is  the  presence  in  it  of  gold  in  paying 
quantities.  It  is  considered  by  Mr.  Curtis  that  an  eruption  of 
rhyolite  caused  the  upheaval  which  made  the  main  fault  in  Ruby 
Hill ;  this  eruption  occurred  in  the  Tertiary  period.  It  is  sup- 
posed that  solfataric  action  decomposed  some  massive  rock  and  so 
formed  metalliferous  solutions,  which  ascended  and,  penetrating 
into  the  limestone,  deposited  the  ore.  Some  of  the  ore  is  pro- 
bably pseudomorphous  after  limestone.  The  average  contents  of 
all  the  Richmond  ore  worked  in  1879  were  : 

Lead        .        .        -33  per  cent. 
Silver      .        .         .     274  oz.  per  ton  (2000  Ib.) 
Gold        .         .  i  -59  oz.      „  „ 

Iron         .         .         .24  per  cent,  corresponding  to  34 
per  cent,  of  Fe2O,. 


78  ORE  AND  STONE-MINING. 

Huanchaca. — The  mines  of  Huanchaca  are  situated  near  the 
town  of  that  name  in  the  department  of  Potosi  in  Bolivia,  at  a 
great  altitude,  for  the  entrance  of  the  San  Leon  adit  is  13, 500  feet 
above  the  level  of  the  sea.  The  silver  lodes  occur  in  a  soft  de- 
composed trachyte ;  the  actual  silver-bearing  mineral  is  fahlerz, 
containing  about  10  per  cent,  of  the  precious  metal.  Fortunately 
for  the  shareholders  the  percentage  of  silver  increases  with  the 
depth  of  the  mine.  The  accompanying  minerals  are  galena, 
blende,  iron  pyrites,  copper  pyrites,  with  heavy  spar  arid  quartz, 
and  rarely  a  little  stibnite  and  pyrargyrite.  The  main  lode  runs 
about  east  and  west,  and  is  from  3  to  10  feet  in  width  (i  to 
3  metres)  ;  it  has  three  particularly  rich  shoots  which  incline 
from  west  to  east.  The  total  output  of  silver  in  1887  was 
4,214,510  oz.  (131,086  kil.). 

At  the  famous  Potosi  mines  also,  the  silver  occurs  in  a  fahlerz. 

Broken  Hill. — The  mines  at  Broken  Hill  are  remarkable  for  their 
enormous  output  of  silver  and  lead  during  the  last  few  years. 
They  are  situated  in  the  Silverton  or  Barrier  Ranges  district  of 
New  South  Wales,  near  the  western  boundary  of  the  colony.  The 
deposit  is  generally  spoken  of  as  a  vein  or  lode,  but  there  seems 
some  doubt  whether  this  appellation  is  correct ;  further  develop- 
ments of  the  workings  may  prove  that  it  is  a  bed.  The  vein,  if  it 
may  be  so  called,  runs,  roughly  speaking,  N.E.  and  S.W. ;  the  dip 
varies,  being  sometimes  to  the  S.E.  and  sometimes  to  N.W.,  and 
is  always  steep.  At  and  near  the  surface,  the  vein  *  consisted  of 
dark-brown  haematite,  often  blackened  by  psilomelane,  together 
with  ferruginous  carbonate  of  lead,  kaolin,  and  the  chloride,  chloro- 
bromide  and  iodide  of  silver;  besides  these  there  were  pyromorphite, 
atacarnite,  cuprite,  malachite,  and  chrysocolla,  with  quartz, 
quartzite,  and  garnet  rock.  Below  this  upper  weathered  zone, 
containing  minerals  usually  met  with  in  gozzans,  come  the 
sulphides,  especially  galena  and  zinc  blende,  together  with  pyrites, 
chalcopyrite,  and  mispickel.  Some  of  the  galena  is  so  intimately 
mixed  with  the  blende  as  to  render  its  separation  by  any  ordinary 
dressing  process  very  difficult,  if  not  commercially  impossible. 
Ores  of  this  class  f  contain  15  to  40  per  cent,  of  lead,  15  to  30 
per  cent,  of  zinc,  and  8  to  24  ounces  of  silver  to  the  ton,  and  at 
present  the  owners  of  the  mines  have  not  settled  what  method  of 
treatment  will  prove  the  most  efficacious  and  economical.  The 
width  of  the  lode  is  from  15  to  316  feet.  The  enclosing  rocks  are 
gneiss  and  garnetiferous  mica  and  talcose  schists,  and  the  vein  lies 

*  John  Provis,  "  Report  on  the  Broken  Hill  Proprietary  Co.'s  Mines," 
contained  in  the  Company's  Reports  and  Statements  of  Accounts  for  the  Half 
Year  ended  Nov.  yotli,  1886.  Melbourne,  Victoria.  Jamieson  and 
Howell,  "Mining  and  Ore-treatment  at  Broken  Hill,  N.S.W.,"  Proc.  List. 
C.E.,  vol.  cxiv.  (1892-93),  Part  IV. 

t  Schnabel,  "  Vorschlage  zur  Verarbeitung  australischer  silberhaltiger 
Blende-Bleiglanzerze,"  B.  u.  h.  Z.,  1882,  p.  429. 


MODE  OF  OCCURRENCE  OF  MINERALS.          79 

parallel  to  the  planes  of  foliation.  In  the  seven  years  ending 
3ist  May,  1892,*  the  principal  mine,  owned  by  the  Broken  Hill 
Proprietary  Company,  produced  984,349  tons  of  ore,  which  yielded 
36,512,445  ounces  of  silver  and  151,945  tons  of  lead,  worth 
altogether  ^8, 252,138,  of  which  ^£3, 896,000  has  been  paid  in 
dividends  and  bonus. 

Silver-bearing  Sandstone.  —  Silver  is  found  in  workable 
quantities  in  certain  beds  of  sandstone,  interstratified  with  shale, 
considered  to  be  of  Triassic  age,  at  Stormont  in  Southern  Utah.f 
All  the  strata  contain  at  least  some  traces  of  silver,  but 
three  or  four  special  horizons  were  rich  enough  to  be  worked ; 
even  here  the  precious  metal  was  distributed  irregularly,  and 
mining  was  confined  to  rich  "  shoots  "  or  chimneys,  which  some- 
times followed  one  particular  stratum  of  the  general  ore-bearing 
bed,  and  sometimes  cut  across  it.  It  is  supposed  that  silver- 
bearing  solutions  came  up  through  the  rock,  and  flowed  along 
the  portions  which  they  found  most  porous.  The  precipitation 
of  the  silver  was,  perhaps,  caused  by  the  presence  of  organic 
matter.  The  metal  exists  in  the  form  of  sulphide  and  chloride, 
though  there  is  a  little  native  silver.  These  minerals  are  dissemi- 
nated through  the  sandstone,  and  occur  especially  along  the 
planes  of  bedding  and  of  fracture.  The  ore-beds  were  mined  for 
a  thickness  of  six,  eight,  or  even  ten  feet,  though  the  whole  of 
the  rock  was  not  always  worth  milling.  Much  of  the  ore  milled 
about  1879  contained  from  20  to  30  oz.  of  silver  per  ton,  and 
yielded  by  amalgamation  15  to  24  oz4 

Garfield  Mine,§  near  Calico,  California,  owes  its  existence  to  a 
network  deposit  or  stockwork.  The  surrounding  rock  is  liparite 
or  rhyolite,  which  is  traversed  near  by  a  number  of  irregular 
fissures.  The  cracks  contain  kerargyrite  and  embolite,  with  chry- 
socolla  and  heavy  spar,  and  the  stockwork  may  be  described  as  a 
breccia  of  liparite  cemented  by  the  argentiferous  and  other 
minerals. 

Slate. — Wales  is  so  renowned  for  its  slate  that  the  example  of 
a  deposit  of  this  mineral  may  fairly  be  taken  from  the  Principality. 
About  two-thirds  of  the  Welsh  slate  are  got  from  beds  of  Cambrian 
age  in  Carnarvonshire,  and  one-third  from  beds  in  the  Lower 
Silurian  (Ordovician)  rocks  in  Merionethshire.  The  quarries  in 
the  former  county  are  mostly  open,  whilst  in  the  latter  the  local 
conditions  have  led  to  the  adoption  of  true  mining,  especially  at 
Festiniog,  which  can  boast  of  the  most  extensive  underground 

*  Company's  Half -Yearly  Report,  dated  July  27,  1892,  p.  86. 

t  R.  P.  Rothwell,  "Report  on  the  Stormont  Silver  Mining  Company's 
Property,  Silver  Reef."  Utah,  1879. 

+  Jackson,  "  Silver  in  Sedimentary  Rocks,"  fieport  of  the  Directors  of  the 
U.S.  Mint.  Washington,  1881,  p.  384. 

§  W.  Lindgren,  "  The  Silver  Mines  of  Calico,  California,"  Trans.  Amer. 
Inst.  M.K,  vol.  xv.  (1886-87)  p.  725. 


8o 


ORE  AND  STONE-MINING. 


workings  for  slate  in  the  world.  The  northern  part  of  the  parish 
of  Festiniog  is  occupied  by  the  outcrop  of  a  thick  series  of  slaty 
rocks  (K,  Fig.  67*),  resting  upon  coarse  volcanic  agglomerate,  H, 
and  interstratified  with  thinner  beds  of  volcanic  ash,  and  inter- 
sected from  time  to  time  by  intrusive  dykes  of  diabase,  locally 
called  whinstone.  The  beds  have  a  general  northerly  or  north- 
westerly dip  of  20°  to  35°,  whilst  the  cleavage  planes  throughout 
the  district  dip  at  a  greater  angle  than  the  bedding  by  about  1 5°, 
and  very  nearly  in  the  same  direction. 

Owing  to  peculiarities  of  texture,  due  apparently  to  the  fineness 
of  the  sediment  deposited  upon  the  old  sea-bottom,  certain  beds 
or  sets  of  beds  furnish  a  slate  which  can  be  split  into  very  smooth 
sheets,  as  thin  as  T\  inch  and  even  less.  Any  set  of  beds  worked 
as  a  whole  is  known  locally  as  a  "  vein,"  but  it  does  not  necessarily 
furnish  saleable  roofing  material  for  its  entire  thickness.  Some- 


Dolwen. 


Foel  Rydd. 


A,  granite  ;  B,  Tremadoc  rocks  ;  C,  Garth  Grit ;  D,  Lower  Slate  ; 
E,  Arenig  rocks  above  the  grit ;  F,  Lower  Agglomerate;  F',  Middle 
Agglomerate ;  G',  Middle  Slate;  G,  Upper  Slate ;  H,  Upper  Agglomer- 
ate ;  K,  Llandeilo  slates. 

times  unprofitable  rock  is  taken  away  above  the  good  slate  in 
order  to  reach  a  firm  layer,  such  as  a  bed  of  volcanic  ash,  or  a 
"  whinstone  "  dyke,  which  can  be  trusted  to  stand  as  the  roof  of 
the  underground  chambers,  and  at  others  the  fine-grained  slate 
has  beds  of  coarser  sediment  interstratified  with  it,  which  cause 
irregularities  in  the  planes  of  cleavage,  and  so  give  rise  to  inferior 
products. 

The  "  Old  Vein,"  famous  for  the  quality  of  its  slates,  is  120  feet 
(36.5  m.)  thick  at  the  Oakeley  quarries,  where  other  "  veins  "  of 
less  importance  are  also  being  worked  (Fig.  68).  At  some  of  the 
other  quarries  of  the  district,  beds  of  slate  in  the  underlying 
rocks  of  the  Arenig  series  are  found  to  be  profitable,  such  as  G' 
in  Fig.  67,  and  i  in  Fig.  68. 

The  property  possessed  by  the  slate  of  rending  along  planes, 
cutting  across  both  dip  and  cleavage,  must  not  be  forgotten,  for 
upon  it  depend  both  the  getting  of  the  rock  and  the  direction 
given  to  the  supporting  pillars.  At  the  Oakeley  quarries  the  "line 

*  Jennings  and  Williams,  "  Manod  and  the  Moelwyns,"  Q.  J.  Geol.  Soc. 
vol.  xlvii.  (1891),  p.  368. 


MODE  OF  OCCURRENCE  OF  MINERALS, 


81 


of  pillaring,"  that  is  to  say,  the  direction  along  which  the  cross- 
rending  or  rifting  takes  place  most  readily,  runs  about  N.  7°  W., 
whereas  the  dip  is  N.  40°  W.  The  planes  along  which  the  slate 
rends  or  "  pillars  "  best  are  at  right  angles  to  the  cleavage  planes, 
not  quite  vertical,  but  dipping  at  a  high  angle  to  the  east;  the 
consequence  is  that  the  eastern  side  of  an  underground  chamber 
at  these  quarries  overhangs  slightly. 

The  value  of  a  slate  bed,  or  "  vein,"  depends  greatly  upon  the 
number  and  nature  of  the  natural  joints  by  which  it  is  intersected. 
If  they  are  very  numerous,  the  workings  will  yield  blocks  too 
small  for  making  the  larger  and  higher  priced  sizes  of  slates ;  if 
they  are  rare,  more  expense  will  be  incurred  in  severing  the 
material  from  its  bed.  Disturbances  of  the  strata  resulting  in 

FIG.  68. 
SECTION  OF  THE  OAKELEY  QUARRIES,  FESTINIOG.* 


Ag1,  Ag2,  Ag,  volcanic  agglomerates ;  i,  slate  vein  worked  at 
Wrysgan  and  New  Quarry,  Diphwys  ;  2,  new  or  south  vein ;  3, 
old'vein  ;  4,  2A  vein  ;  5,  back  vein  ;  6,  north  vein  ;  WD,  "  whin- 
stone  "  dykes  (diabase) ;  P,  porphyrite  ;  As,  volcanic  ash. 

fissures  filled  either  mechanically  with  clay  and  broken  slate,  or 
chemically  by  the  deposition  of  quartz,  may  render  the  "  vein  " 
utterly  worthless  in  places ;  but,  as  in  the  case  of  other  bedded 
deposits,  changes  in  productiveness  are  far  less  frequent  than 
with  lodes. 

Sulphur. — The  industrial  sources  of  sulphur  are  :  (i)  deposits 
of  native  sulphur,  and  (2)  iron  pyrites. 

Native  sulphur  occurs  as  a  product  of  volcanic  emanations,  and 
in  sedimentary  deposits. 

The  amount  of  sulphur  obtained  from  deposits  of  volcanic 
origin  is  small ;  but  this  mode  of  occurrence  is  of  geological 
interest,  because  we  can  observe  the  processes  of  accumulation  in 
actual  operation,  whereas  usually  the  secrets  of  Nature's  laboratory 
are  hidden  from  us. 

*  Made  by  Mr.  G.  J.  Williams,  F.G.S. 


82  ORE  AND  STONE-MINING. 

Deposits  of  this  kind  are  generally  found  at  or  near  spent  vol- 
canic craters,  the  emanation  of  sulphurous  gases  being  one  of  their 
last  signs  of  activity.  Sulphur  has  been  worked  on  a  small  scale 

at  the  famous  Solfatara  of 

FIG.  69.  Pozzuoli,   near    Naples,    at 

Yulcano,  one  of  the  Lipari 
Islands,  and  in  volcanic  re- 

(</ '"Jk      f'f.  "jjf)     ('£  I  *)*}  gions  in  various  parts  of  the 

((,    Vi       Kill         H#j^  world. 

U^¥          \ !  ft  In  Iceland  a  little  column 

of  vapour  may  be  seen  issu- 
ing from  the  ground,  and  the 
low  mound  around  it  con- 
sists of  a  crust  of  sulphur 
covered  by  a  thin  coating  of 
blown  sand.  The  gases  com- 
ing out  of  the  earth  contain 
sulphuretted  hydrogen  in 
addition  to  steam,  and 
when  they  reach  the  surface  some  of  the  former  is  oxidised, 
and  sulphur  is  deposited  as  shown  in  Fig.  69  ;  a  is  the  under- 
lying rock,  a  decomposed  lava,  b  clay,  c  the  native  sulphur, 
and  d  sand  blown  over  the  little  mound,  and  retained  by  the 
moisture  due  to  condensation  of  the  steam.  I  have  already  alluded 
to  Sulphur  Bank  and  Steamboat  Springs,  in  speaking  of  quick- 
silver. 

Seams  or  beds  of  sulphur  occur  in  Sicily,  Calabria,  the  Romagna, 
and  other  parts  of  Italy,  and  also  in  Croatia,  Spain,  and  France. 
By  far  the  most  important  beds  are  those  of  Sicily. 

The  accompanying  section,  borrowed  from  Baldacci*  (Fig.  70), 
shows  a  section  of  the  country  near  Caltagirone.  The  letter  a 

FIG.  70. 


denotes  beds  of  clay  (Tortonian),  b  is  tripoli  (Sarmatian),  c  is  the  bed 
of  sulphur-bearing  limestone,  d  white  marl  or  marly  limestone  with 
foraminifera,  called  "  trubi "  in  Sicily ;  e,  blue  clay ;  /,  calcareous 
tufa.  The  beds  a,  6,  c  are  considered  to  belong  to  the  Upper 
Miocene,  whilst  d  is  placed  in  the  Lower  Pliocene,  and  e  and^in 
the  Upper  Pliocene. 

The  beds  of  tripoli  are  made  up  chiefly  of  the  siliceous  remains 
of  radiolaria,  diatomacese,  and  sponges,  together  with  marl. 

*  Descrizione  geologka  delV  Isola  di  Sicilia.    Borne,  1886,  p.  296. 


MODE  OF  OCCURRENCE  OF  MINERALS.          83 

The  sulphur-bearing  bed  varies  from  a  hard  white  limestone 
to  a  grey  marly  limestone,  and  from  this  to  a  marl ;  the  sulphur 
itself  is  always  in  the  native  state,  forming  little  globules,  laminae, 
or  irregular  lenses,  varying  in  thickness  and  extent.  It  is  often 
crystallised,  and  associated  with  it  are  celestine,  gypsum,  calcite, 
and  arragonite  ;  in  the  clayey  beds  there  is  also  bitumen,  which 
is  objectionable,  as  it  gives  a  dark  colour  to  the  product  obtained 
by  liquation. 

The  thickness  of  the  sulphur  seams  varies  within  very  wide 
limits.  Beds  20  feet  thick  are  common,  and  at  Lercara  the 
stratum  reaches  the  enormous  thickness  of  164  feet  (50  m.). 
Frequently  there  are  two  or  three  beds ;  at  the  great  Somatino 
mine,  for  instance,  the  deposit  is  100  to  115  feet  (30  to  35  m.) 
thick,  divided  into  six  separate  seams,  from  6  to  25  feet  (2  to  8  m.) 
each,  by  partings  of  barren  rock. 

As  a  rule,  a  bed  less  than  5  feet  (1.50  m.)  in  thickness  is  not 
worth  working,  unless  it  is  exceptionally  rich  or  conveniently 
situated  for  working. 

The  yield  of  the  sulphur  rock  may  be  taken  on  an  average  at 
about  22  per  cent.,  though  occasional  rich  seams  give  as  much  as 
45  per  cent. 

Parodi*  subdivides  the  seams  according  to  quality,  thus  : 

Amount  of  Sulphur. 

By  Analysis.  Actual  Yield  by  the  Kilns. 

Per  cent.  Per  cent. 

Very  rich        .         .         .         .     30  to  40  20  to  25 

Kich        .         .         .         .         .     25  „  30  15  ,,  20 

Poor 15  „  25  10  ,,  15 

The  Sicilian  deposits  are  considered  to  have  been  formed  by 
chemical  precipitation  from  aqueous  solutions  in  lakes.f 

The  deposits  on  the  Italian  mainland  also  belong  to  the  Miocene 
period,  and  the  sulphur  beds  are  known  to  extend  for  a  long 
distance  on  the  east  of  the  Apennines.  Often  there  is  but  one 
seam  6  to  10  feet  (2  to  3m.)  thick  ;  the  rock  is  poorer  than  in 
Sicily,  for  it  contains  only  18  to  20  per  cent.,  and  the  yield  by 
the  kiln  (calcarone)  does  not  exceed  1 2  per  cent,  on  an  average. 

After  the  description  of  the  deposits  of  cupreous  pyrites  at 
Rio  Tinto,  it  is  quite  unnecessary  to  say  anything  further  about 
such  sources  of  sulphur.  Iron  pyrites  containing  no  copper  is 
sometimes  worked,  and  Cae  Coch  Mine,  in  Carnarvonshire, 
affords  an  example  of  a  deposit  of  this  kind! 

Tin. — Tin  ore  is  obtained  from  veins,  beds,  and  a  variety  of 
irregular  deposits. 

It  is  natural  for  an  Englishman  to  take  his  illustrations  of 

*  fSuW  estrazione  dello  Solfo  in  Sicilia.     Florence,  1873,  P-  Io- 
t  "  Notizie  sulle  condizioni  dell'  industria  solfifera  e  di  quelle  ad  essa 
affini,"  Rivistadel  servizio  miner ario  nel  1888,     Florence,  1890,  p.  clxv. 


84 


ORE  AND  STONE-MINING. 


veins  from  Cornwall.    Figs.  71  and  72  represent  two  veins  in  the 
parish  of  St.  Agnes.* 


FIG.  71. 


FIG.  72. 


A,  slate  (Idllas)  ;  B,  capel— that  is  to 
say,  slate  altered  into  a  hard  dark- 
coloured  mass  of  quartz  and  schorl, 
with  short  lenticular  veins  of  quartz, 
and  traversed  by  little  strings  of  cas- 
siterite  and  chlorite ;  CO,  the  leader, 
consisting  of  quartz,  cassiterite,  chlo- 
rite, a  little  iron  pyrites,  and  pieces  of 
capel. 


CENTIMETRES  ' — 


75     iO     25      0 


AA,  slate  (Jcillas)]  BB,  capel 
as  above  ;  CC,  small  leader  or 
vein  of  tinstone  and  quartz  ;  DD, 
main  leader,  consisting  of  iron 
pyrites,  cassiterite,  and  chlorite, 
containing  about  2^  per  cent,  of 
tinstone. 


Many  of  the  veins  in  granite  are  due  to  the  alteration  of  the 
rock  in  the  neighbourhood  of  fissures,  as  has  been*  already 
explained  (Fig.  3).  The  so-called  carbonas  of  the  St.  Ives  district 
are  essentially  masses  of  stanniferous  schorl  rock,  very  irregular 
in  shape  and  connected  with  a  main  lode  by  a  cross  joint  or  fissure. 
They  seem  to  be  altered  granite. 

Mulberry  Mine,  near  Bodmin  (Fig.  16),  has  already  been  cited 
as  an  instance  of  a  network  deposit  or  stockwork. 

At  Altenberg,  in  Saxony,  there  is  a  huge  mass  of  tin-bearing 
rock,  locally  known  as  "Zwitter"  or  "Zwittergestein."  Von  Cottaf 
has  shown  by  analyses  that  it  is  merely  granite,  which  has  lost 
about  3  per  cent,  of  silica  and  2  per  cent,  of  potash,  and  has 
taken  up  about  4  per  cent,  of  ferrous  oxide  and  J  per  cent,  of 
oxide  of  tin.  It  has  been  worked  for  tin  during  a  period  of 
several  centuries. 

Beds  containing  tin  ore  in  the  form  of  rolled  pebbles  and 
sand  occur  with  the  alluvial  deposits  of  existing  valleys  in 
many  countries.  The  principal  Cornish  deposits  have  long 

*  C.  Le  Neve  Foster,  "  Remarks  upon  some  Tin  Lodes  in  the  St.  Agnes 
District,"  Trans.  R.  Geol,  Soc.  Cornwall,  vol.  ix.  p.  206, 

t  B.  von  Cotta,  J*  Die  Steingruppe  im  Hofe  der  Bergakademie,"  Fest- 
schrift zum  Tiundertjahrigen  Jubildum  der  Koniyl.  Sachs.  Bergakademie  zu 
Freiberg.  Dresden,  1886,  p.  157. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


been  exhausted,  though  as  lately  as  1873  tin  ore  was  raised 
from  a  bed  under  Restronguet  Creek,  a  branch  of  Falmouth 
Harbour  (Fi<r.  364).  In  the  Malay  Peninsula  alluvial  deposits  or 
"stream  works"  are  yielding  large  quantities  of  ore;  and  New 
South  Wales  is  remarkable  not  only  for  its  recent  stanniferous 
alluvia,  but  also  for  much  older  deposits,  which,  like  the  ancient 
gold  gravels,  have  been  preserved  under  a  covering  of  basalt.  The 
accompanying  map  (Fig.  73)  shows  part  of  Vegetable  Creek,  New 
South  Wales ;  the  stippling  by  the  side  of  the  creek  represents 
the  tin-bearing  alluvium,  which  has  been  worked  by  open  pits. 
The  rest  of  the  country  is  granite,  except  the  shaded  part  at  AB 

FIG.  73. 


B  ^^^ 


^*^r?;§S>. 

3&-S? 


which  denotes  basalt ;  this  flowed  down  an  old  valley  and  filled  it 
up  entirely,  as  shown  by  the  section  (Fig.  74).  The  hard  cover  of 
lava  has  preserved  the  stanniferous  alluvium  and  the  white  clay 
from  denudation.  Old  alluvia  of  this  description  are  known  as 
"deep  leads." 

Zinc. — Zinc  ore  is  found  in  veins,  beds,  and  irregular  masses. 

Liiderich  mine,  situated  near  Bensberg,  on  the  right  bank  of 
the  Rhine,  not  very  far  from  Cologne,  derives  large  quantities  of 
blende  from  a  huge  vein  in  the  Devonian  rocks.  The  actual 
horizon  is  that  of  the  "  Lenneschiefer,"  which  is  classed  as  Middle 


86 


ORE  AND  STONE.MINING. 


Devonian.  The  rocks  are  slate,  interstratified 
with  sandstone  and  slaty  sandstone.  The  lodes 
of  the  district,  as  a  rule,  run  E.  and  W.,  or  a 
little  north  of  west ;  the  Liiderich  mine,  however, 
is  an  exception,  for  the  lode  strikes,  roughly 
speaking,  north  and  south.  It  may  be  best  de- 
scribed as  a  zone  or  belt  of  broken  and  disturbed 
rock,  40  to  50  metres  wide,  containing  ore  in 
irregular  veins  and  masses.  The  ore-bodies  are 
usually  lenticular  in  shape,  dying  out  gradually 
in  every  direction ;  they  sometimes  consist  of 
solid  blende  for  a  width  of  several  yards.  The 
minerals  found  in  the  lode  are :  blende,  galena, 
copper  pyrites,  iron  pyrites,  fahlerz,  quartz  and, 
rarely,  chalybite.  The  fahlerz  is  silver-bearing, 
and  the  blende  always  contains  cadmium, 
and  occasionally  gallium.  The  total  production 
of  the  mine  in  1890  was  8304  tons  of  blende 
ready  for  the  smelter,  and  423  tons  of  lead  ore. 
It  is  therefore  of  more  importance  as  a  zinc 
mine  than  any  in  this  country. 

The  largest  zinc  mine  in  the  British  Isles  at 
the  present  time  is  Minera,  near  Wrexham.  It 
may  be  safely  inferred  from  its  name  that  it 
was  worked  during  the  Roman  occupation  of  the 
country ;  but  the  object  of  the  mining  in  those 
days,  and,  indeed,  until  quite  a  recent  date,  was 
lead  and  not  zinc  ore. 

The  surrounding  rocks  are  Carboniferous 
Limestone  and  Millstone  grit,  and  as  the  lode 
is  a  well-marked  fault,  the  Coal  Measures  are 
met  with  on  the  downthrow  side.  There  are 
two  principal  veins  running  parallel  to  one 
another  in  a  general  N.W.  and  S.E.  direction, 
and  dipping  steeply  to  the  N.E. ;  and  where  pro- 
ductive they  are  nearly  perpendicular.  They 
vary  in  size  from  a  mere  cleft  in  the  rock  to  a 
width  of  1 8  feet ;  a  fair  average  size  is  6  feet. 
Besides  these  two  main  veins  there  are  numerous 
branches  and  ramifications.  The  valuable  mine- 
rals are  zinc  blende  and  galena,  and,  as  would 
be  expected,  the  matrix  consists  mainly  of  calc- 
spar.  In  the  upper  parts  of  the  mine  to  a  depth 
of  220  yards,  galena  was  met  with  in  large  quan- 
tities, and  the  mine  made  considerable  profits  upon 
its  sales  of  lead  ore ;  but  during  the  last  twelve 
years  blende  has  greatly  predominated.  At  the 
present  time  it  may  be  reckoned  that  the  "  stuff  " 


MODE  OF  OCCURRENCE  OF  MINERALS.          87 

brought  up  from  the  mine  yields  yj  percent,  of  blende  and  i^  per 
cent,  of  galena.  The  total  production  of  the  mine  in  1891  was 
5433  tons  of  zinc  ore  and  906  tons  of  lead  ore  ready  for  the 
market.o 

At  *Ammeberg,  near  the  northern  extremity  of  the  Wetter 
Lake,  in  Sweden,  zinc  blende  occurs  in  beds.  The  surround- 
ing rock  is  a  schist  consisting  of  felspar  and  quartz,  with  a  little 
mica,  which  may  be  regarded  as  a  variety  of  gneiss.  The  blende 
is  accompanied  by  iron  pyrites,  pyrrhotine,  hornblende,  chlorite, 
garnet,  tourmaline  and  other  minerals,  and  in  places  it  may  be 
plainly  seen  to  replace  the  mica  of  the  gneiss.  The  Ammeberg 
beds  are  worked  on  a  large  scale  by  the  Vieille  Montagne 
Company. 

Diepenlinchen  mine,  near  Stolberg,  in  Prussia,  is  interesting 
not  only  on  account  of  being  a  large  producer  of  zinc  ore,  but  also 
because  some  of  it  is  derived  from  a  great  stockwork,  a  form  of 
deposit  less  common  with  zinc  than  tin.  The  stockwork  consists 
of  an  oval  mass  of  limestone,  about  120  metres  long  from  east  to 
west,  and  50  metres  across  from  north  to  south.  In  this  region 
the  limestone  is  full  of  cracks,  which  have  been  filled  up  with 
zinc  blende,  and  this  mineral  is  also  seen  lining  small  irregu- 
lar cavities  in  the  rock;  judging  by  its  structure  it  has  been 
deposited  layer  after  layer,  and  probably  from  an  aqueous  solution. 
The  rock  is  so  intermingled  with  blende  that  the  whole  of  it 
has  to  be  worked  away,  and  the  separation  of  the  valuable  con- 
stituent from  the  waste  is  effected  by  dressing. 

Fig.  15  is  a  section  across  one  of  the  irregular  masses  of 
calamine  at  Altenberg,  in  the  neutral  territory  of  Moresnet,  be- 
tween Belgium  and  Prussia. 

FAULTS. — All   kinds   of   deposits   are  subject  not  only  to 
irregularities  dependent  upon  their  mode  of  formation,  such  as  a 
gradual  thinning  out  or  thickening, 
but  to  others  which  have  taken  place  FIG.  75. 

subsequently.      Sometimes   a    bed,       _T_1 

such  as  AB,  has  had  a  portion  de-       -\— V-  *— -v  '--+—*! — K  ~w  ~i~~v 

nuded    by  a    current   during    the       .  .•  -.  •' ;  0..-  -..-'.  -.  •-•'  ;'..-  .;  .• 

general  period  of  deposition.     Such 

an   occurrence   is   called   a   "wash  ^  _ 

out "    fault,    or     "  dumb     fault  "       ^~-^^-— ^  r-^vq-fr 

(Fig.  75)-. 

In  addition  to  irregularities  of  this  kind,  deposits  suffer  from 
the  disturbances  which  have  taken  place  in  the  rock  masses  which 
contain  them.  Slight  undulations  of  the  strata  are  common,  and 
when  the  disturbance  has  been  greater,  the  beds  are  bent  into 
arches  and  troughs,  or  anticlinals  and  synclinals.  Further,  a 

*  A.  von  Groddeck,  Die  Lelire  von  den  Lagerstdtten  der  Erze.  Leipsic 
1879,  p.  in. 


88 


ORE  AND  STONE-MINING. 


FIG.  76. 


lateral  pressure  may  have  been  sufficient  to  cause  great  crumplings 
and  contortions,  and  in  places  to  invert  the  order  of  succession,  in 
other  words  to  make  the  newer  beds  lie  under,  instead  of  above, 
the  older  ones.  When  beds  are  much  bent  there  is  often  a 
thickening  in  the  anticlinals  and  synclinals,  and  a  corresponding 
thinning  in  the  connecting  limbs. 

A  bed  may  be  so  folded  and  crumpled  as  to  lose  its  original 
sheet-like  form  in  places,  and  assume 
the  shape  of  an  irregular  mass. 
This  may  happen  even  with  a  coal 
seam.* 

The  disturbances  of  the  rocks  may 
finally  produce  rents,  accompanied  by 
displacement,  which  are  called  faidts, 
heaves,  throws,  or  slides. 

We  will  take  the  case  of  a  bed 
(Fig.  76).  AB  is  a  seam  which  ends 
suddenly  at  B,  whilst  the  continua- 
tion is  found  at  a  lower  level,  CD.  The  two  parts  of  the  bed 
must  have  originally  been  on  the  same  horizon,  but  subsequently 
a  fracture  took  place  along  the  line  XY,  followed  by  a  movement 
of  one  side  or  both  sides.  As  a  rule  the  portion  of  rock  on  the 
upper  or  hanging  wall  side  appears  to  have  slid  downwards,  or 
the  under  portion  to  have  been  thrust  upwards. 

The  rent  may  be  clean,  sharp,  and  narrow,  with  the  shifted 
portions  of  rock  touching  each  other ;  or  there  may  be  a  suc- 


FIG.  77. 


FIG.  78. 


cession  of  fissures  producing  a  step-like  arrangement  of  the  seam 
(Fig.  77) ;  frequently  the  cracks  are  filled  up  with  clay,  or  there 
is  a  zone  several  yards  in  width  composed  of  broken  fragments 
and  clay,  produced  by  the  attrition  of  the  sides  of  the  two  rock 
masses  (Fig.  78).  Signs  of  rubbing  may  be  seen  upon  the  walls 

*  J.  Gallon,  Lectures  on  Mining,  vol.  i.  p.  63,  and  Atlas,  Plate  VIII., 

Fig.  44- 


MODE  OF  OCCURRENCE  OF  MINERALS, 


89 


FIG.  79. 


in  the  form  of  grooves  and  scratches,  or  polished  surfaces  known  as 
"  slickensides."  A  fault  is  of  the  same  origin  as  a  mineral  vein  ; 
the  filling  is  due  either  to  mechanical  or  chemical  agencies,  or  to 
both  combined,  but  does  not  happen  to  be  worth  working  com- 
mercially. The  prolongation  of  a  valuable  mineral  vein  may 
be  unproductive  on  entering  certain  rocks,  and  will  then  be  looked 
upon  as  a  fault.  Thus,  some  of  the 
mineral  veins  of  the  Carboniferous 
Limestone  in  Flintshire  appear  to  be 
continued  as  faults  in  the  Coal  Measures. 

The  throw  of  a  fault  is  measured  by 
the  amount  of  vertical  displacement.  If 
XY  is  a  fault  shifting  a  bed  AB  (Fig. 
79),  draw  BE  vertical  and  CF  at  right 
angles  to  BE.  Then  BF  is  the  vertical 
dov,rnthrow,  CF  represents  the  horizontal 
displacement,  and  BC  the  shift  along  the 
line  of  dip. 

The  study  of  faults  is  important  be- 
cause the  miner  working  the  bed  AB  (Fig.  78),  wants  to  know  after 
reaching  the  fault  XY  where  to  find  the  continuation  of  the  de- 
posit. The  rule  is  to  follow  the  greater  angle.  The  angle  ABY 
is  greater  than  the  angle  ABX,  and  the  missing  part  may  be 
expected  somewhere  along  the  line  BY.  If  the  miner  were  work- 
ing from  D  to  C,  the  same  rule  would  apply,  for  the  angle  DCX 
is  greater  than  DCY. 

This  rule  gives  the  direction  of  the  throw,  but  affords  no  indi- 
cation as  to  its  amount,  which  may 
vary  considerably.  If  the  beds  are 
distinctly  marked  by  lithological  pe- 
culiarities or  by  fossils,  the  miner 
can  obtain  useful  information  by 
driving  through  the  fault  into  the 
rocks  upon  the  other  side.  Suppose, 
for  instance,  that  a  valuable  bed  of 
shale  AB  (Fig.  80)  ended  off  suddenly 
ao-ainst  a  fault  FG.  A  continuation 
of  the  workings  in  the  direction  AB 
comes  upon  a  bed  of  conglomerate, 
which  the  miner  recognises  as  one 

that  is  usually  40  feet  above  him.  He  can  fairly  conclude  that 
the  distance  BE  at  right  angles  to  the  prolongation  of  DC  will 
be  40  feet.  As  the  respective  dips  of  the  bed  and  of  the  fault  are 
known,  the  angle  EBC  can  at  once  be  ascertained  and  the  distance 
BC  calculated. 

The  throw  of  a  fault  is  not  always  the  same ;  it  varies  along  the 
strike,  and  finally  dies  away  altogether.  This  will  be  understood 
by  making  a  slit  with  a  penknife  through  a  sheet  of  cardboard 


FIG.  80. 


90  ORE  AND  STONE-MINING. 

or  india-rubber,  and  pressing  down  one  side ;  the  throw  dimin- 
ishes from  a  maximum  at  C  to  nothing  at  A  and  B  (Fig.  81). 
Change  in  the  direction  of  throw  may  be  due  to  the  beds  on 

FIG.  8 1.  FIG.  82. 


one  side  of  a  fault  being  puckered  or  bent,  whilst  they  are  flat  or 
dip  evenly  on  the  other  (Fig.  82). 

The  distance  to  which  some  faults  may  be  traced  is  very  great. 
The  Gorze-Ars-Metz  fault*  extends  from  St.  Julien  in  France, 
right  across  Lorraine  to  beyond  the  Saar,  near  Wacheren,  a  total 
distance  of  53  miles  (85  kilometres),  and  another  fault  in  the 
same  district  is  known  for  28  miles  (45  kilometres).  The  throw 
of  a  fault  varies  from  a  few  inches  to  hundreds  and  even  thousands 
of  feet. 

Near  a  fault  a  bed  is  often  found  to  dip  more  steeply,  as  if  it 
had  been  bent  before  it  broke.  This  is  the  case  with  the  great 
iron  ore  bed  of  Lorraine.f  The  usual  dip  is  very  slight,  only  i  to 
2 1  in  a  hundred,  but  near  faults  it  is  decidedly  more,  and  reaches 
4  in  a  hundred. 

The  rule  that  the  portion  of  the  hanging  wall  side  has  shifted 
downwards  along  the  dip  of  the  fault  is  not  without  exceptions, 
FIG.  83.  FIG.  84. 


especially  in  localities  where  rocks  are  much  bent  and  folded. 
Heim  shows  by  a  series  of  figures  the  various  stages  in  the  pro- 
duction of  a  displacement  of  this  kind,  which  is  known  as  a 
reversed  or  overlap  fault  (Fig.  83).  Fig.  84  also  shows  a  reversed 
fault. 

As  mineral  veins  have  been  formed  in  regions  where  rocks 
have  been  broken  and  dislocated,  it  is  only  natural  to  expect  that 

*  Wandesleben,  "  Das  Vorkommen  der  oolitischen  Eisenerze  (Minette)  in 
Lothringen,  Luxemburg  und  dem  ostlichen  Frankreiche."  Festschrift 
tmd  Verhandlungen  Der  IV.  Allyemeine  Deutsche  Bcrgmannstay  in  Halle 
(Sadie.}  Halle,  1890,  p.  301. 

f  Ibid.  p.  301. 


MODE  OF  OCCURRENCE  OF  MINERALS. 


PLAN. 


they  also  should  be  affected  by  movements  and  shif tings  of  the 
earth's  crust.  Owing  to  the  fact  that  veins  are  usually  highly 
inclined,  and  that  there  is  often  much  difficulty  in  deciding  how 
the  dislocated  rocks  fitted  together  before  they  were  shifted,  the 
vein  miner  speaks  of  faults  in  different  terms  to  the  bed  miner. 
Instead  of  talking  of  doivntkrows  and  upthroifs,  he  looks  at  the 
shift  produced  sideways  and  calls  it  a 
heave.  The  miner  driving  a  horizontal 
tunnel  AB  (Fig.  85)  in  a  vein,  comes 
into  the  fault  XY  at  the  point  B,  and 
finds  that  his  vein  ends  off  suddenly  ; 
in  order  to  regain  it  he  is  obliged  to 
drive  sideways  in  barren  ground  from 
B  to  C,  where  he  meets  with  the  con- 
tinuation along  the  line  CD.  The 
miner  says  that  there  has  been  a  left- 
hand  heave,  because  whether  driving 
in  the  direction  A  to  B  or  D  to  C, 
he  finds  the  faulted  portion  to  the 
left  hand.  It  is  evident  in  many  cases  from  the  striations  upon 
the  walls  of  the  faults,  that  the  displacement  of  the  two  adjacent 
rock  masses  took  place,  not  along  the  line  of  greatest  dip,  but  in 
a  diagonal  direction,  causing  a  shifting  sideways  as  well  as 
downwards.  Nevertheless,  where  beds  or  veins  are  not  horizontal, 
a  mere  shift  along  the  line  of  dip  is  suffi- 
cient to  cause  a  heave  sideways.  This  will 
be  understood  from  Fig.  86.  Let  AB 
and  CD  represent  two  portions  of  the  lode 
dislocated  by  the  fault  EF.  The  point  B' 
corresponded  originally  with  B,  and  the 
dislocation  was  caused  by  the  simple 
sliding  of  B'  along  the  line  of  dip  of  the 
fault.  Here  again  the  mincer  would  speak 
of  the  heave  as  taking  place  to  the  left. 

The  subject  of  the  heaves  of  lodes  and 

beds   has   been    elucidated    by    Schmidt,*   Zinimermann  t    and 
others. 

Zimmermann's  rule  for  finding  the  lost  part  of  a  vein  on  the 
other  side  of  a  fault  is  as  follows  : 

Lay  down  upon  paper  the  line  of  strike  of  the  lode  and  the 
line  of  strike  of  the  fault  (cross-course),  and  by  construction 
ascertain  the  horizontal  projection  of  the  line  of  their  intersection ; 
from  the  point  where  the  cross-course  was  struck  by  the  lode, 
draw  a  line  at  right  angles  to  the  strike  of  the  former  and 
directed  to  its  opposite  wall.  Notice  on  which  side  of  the  line  of 

*  Theorie  der  Verschiebung  alter er  Gdnpe.     Frankfort,  1810. 
t  Die  Wiederausrichtung  venvorfener  Gange,  Lager  und  Flbtze.     Darm- 
stadt and  Leipsic,  1828. 


FIG.  86. 


92  ORE  AND  STONE-MINING. 

intersection  this  perpendicular  falls,  and,  after  cutting  through 
the  cross-course,  seek  the  heaved  part  of  the  lode  on  that  side. 
Thus  let  AB  (Fig.  87)  represent,  at  some  given  depth,  the  line 

of   strike  of  a  fault  or  cross- 

FIG.  87.  course   dipping  east,  and   CD 

the  line  of  strike  of  a  lode  dip- 
ping south,  and  we  will  sup- 
pose that  in  driving  from  C  to 
D,  in  a  westerly  direction,  the 
fault  has  been  met  with  at  D. 
Knowing  the  dip  of  the  lode 
and  that  of  the  fault,  it  is  easy 
to  lay  down,  on  any  given  scale, 
A'B'  and  C'D',  the  lines  of 
strike  of  the  fault  and  lode 
respectively  at  a  certain  depth, 
say  ten  fathoms,  below  AB. 
The  point  D",  where  A'B'  and  C'D'  meet,  is  one  point  of  the 
line  of  intersection.  Join  D  and  D"  and  prolong  on  both  sides. 
The  line  MN  represents  the  horizontal  projection  of  the  line  of 
intersection  of  the  two  planes.  At  D  erect  DE  at  right  angles 
to  AB,  and  directed  towards  the  opposite  wall  of  the  fault.  As 

FIG. 


DE  falls  south  of  MN,  the  miner,  after  cutting  through  the  fault 
would  drive  in  a  southerly  direction,  and  eventually  strike  the 
lode  again  at  F.  It  will  be  at  once  understood  that  if  the  miner 
were  following  the  lode  from  G  to  F,  the  perpendicular  would  lie 
to  the  north  of  the  line  of  intersection,  and  following  the  rule 
he  would  drive  in  that  direction,  after  cutting  through  the  fault. 

When  several  faults  dislocate  lodes  one  after  the  other  very 
great  complications  may  arise. 

Fig.  88*  is,  fortunately  for  the  miner,  an  unusual  instance  of  a 
succession  of  faults. 


*  J.  W.  Pike,   "  OQ  some  remarkable  He  ft  res   or    Throws  in  Penhalls 
Mine,"  Quart.  Jour.  Geol  tioc.,  vol.  xxii.  (1866),  p.  537. 


(     93     ) 


CHAPTER    II. 

PROSPECTING. 

Chance  discoveries. — Adventitious  finds. — Uses  of  geology. — Associated 
minerals. — Surface  indications  :  form,  colour,  gozzans,  springs,  indica- 
tive plants,  burrows  of  animals.— Shoading.— Hushing. — Piercing. — 
Lode-lights. — Altered  vegetation  and  other  indications. — Old  workings, 
slag  heaps,  ruins. — Names  of  places. — Divining-rod. — Dipping  needle. 
— Qualifications  of  the  prospector. 

Chance  Discoveries. — The  number  of  discoveries  of  valuable 
mineral  deposits  by  pure  chance  is  very  great.  I  will  mention  a 
few  cases,  mostly  recent,  taking  the  minerals  in  alphabetical  order. 

Amber. — Pieces  of  amber  cast  up  on  the  shores  of  the  Baltic 
after  storms,  no  doubt  were  the  first  sources  of  supply  of  the 
mineral,  and  eventually  led  to  a  search  for  the  parent  beds. 

Cobalt. — The  cobalt  ore  recently  worked  in  Flintshire  was  dis- 
covered in  1870,  by  Mr.  Gage,  who  happened  to  test  with  the 
blowpipe  some  black  matter  which  formed  strings  in  the  Carboni- 
ferous Limestone. 

Copper. — The  owner  of  a  sheep  run  on  Yorke's  Peninsula, 
South  Australia,*  picked  up  some  atacamite  on  the  coast  in  1859, 
and  became  convinced  that  there  were  deposits  of  copper  ore 
inland.  In  1860  he  came  across  the  workings  of  a  wombat  which 
had  thrown  out  a  quantity  of  this  green  ore  in  making  its  burrow. 
Pits  were  put  down,  and  the  great  Wallaroo  lode  was  thus  dis- 
covered. Other  lodes  in  the  district  were  afterwards  hit  upon  in 
the  same  way,  or  from  green  ore  thrown  up  by  some  burrowing 
insect. 

Diamonds. — The  fate  of  South  Africa  has  been  wholly  changed 
by  the  finding  of  diamonds.  Mr.  O'Reilly,  a  trader,  describes  his 
discovery  in  these  words  : — 

"In  March  1867,  I  was  on  my  way  to  Colesberg,  from  the 
junction  of  the  Vaal  and  Orange  Rivers ;  I  outspanned  at  Mr. 
Niekerk's  farm,  where  I  saw  a  beautiful  lot  of  Orange  River 
stones  on  his  table,  which  I  examined.  I  told  Niekerk  they 
were  very  pretty.  He  showed  me  another  lot,  out  of  which  I  at 
once  picked  the  '  first  diamond.'  I  asked  him  for  it,  and  he  told 
me  I  could  have  it,  as  it  belonged  to  a  Bushman  boy  of  Daniel 

*  S.  Higgs,  "  Some  Remarks  on  the  Mining  District  of  Yorke's  Peninsula. 
South  Australia,"  Trans.  It.  Geol.  8oc.  Cornwall,  vol.  ix.  p.  127. 


94  ORE  AND  STONE-MINING. 

Jacobs."  Mr.  O'Reilly  then  sent  the  stone  to  Cape  Town  for 
examination,  when  it  turned  out  to  be  a  true  diamond,  worth 
£509." 

The  value  of  the  diamonds  produced  annually  far  exceeds  that 
of  the  gold  of  any  one  of  our  colonies. 

Gold. — The  story  told  of  the  finding  of  gold  in  California,  in 
1848,  is  that  Marshall,  who  was  superintending  a  sawmill,  hap- 
pened to  see  something  glittering  in  the  mill  leat.  It  turned  out 
to  be  gold.  He  found  more  nuggets,  and  soon  the  discovery  was 
noised  abroad. 

In  Australia  the  first  discoveries  of  gold  were  by  chance. 

The  attention  of  Dr.  Plassard  was  directed  to  the  existence  of 
gold  in  Venezuela  from  seeing  some  specimens  in  the  possession 
of  a  native. 

Iron. — Traces  of  soft  haematite,  noticed  among  the  roots  of  an 
overturned  tree,  led  to  the  discovery,  in  1891,  of  the  important 
Biwabikf  iron  mines  of  the  Mesabi  range,  Minnesota. 

Nickel. — The  Sudbury  nickel  deposits  were  discovered  in 
making  a  cutting  for  the  Canadian  and  Pacific  Railway,  and  even 
then  it  was  the  copper  which  first  attracted  notice. 

Phosphate  of  Lime. — In  May  1886,  a  geologist,  M.  Merle,  took 
it  into  his  head  to  analyse  the  sand  of  an  apparently  abandoned 
pit,  which  had  been  worked  for  centuries  in  order  to  give  bricks 
a  violet  tint  much  esteemed  in  the  neighbourhood.  He  found  it 
contained  77^85  per  cent,  of  phosphate  of  lime.  This  was  the 
origin  of  the  workings  in  the  Upper  Chalk  at  Beau val,  in  the 
department  of  the  Somme.t 

The  discovery  of  the  phosphate  beds  of  Florida§  was  made  in  the 
autumn  of  1889  by  an  orange-grower,  who  out  of  curiosity  sent 
to  a  chemist  a  sample  of  the  white  subsoil  of  his  grove;  this 
turned  out  to  contain  80  per  cent,  of  phosphate. 

Quicksilver. — The  Redington  Quicksilver  Mine,||  in  California, 
was  discovered  in  making  a  cutting  for  a  road. 

Silver. — A  man  made  a  fire  to  cook  his  food  and  protect  himself 
from  the  cold,  near  the  site  of  Catorce,fl  in  Mexico,  and  in  the 
morning  found  silver  shining  in  the  ashes.  This  was  in  1775^ 

*  T.  Keunert,  "  Diamond  Mining  at  the  Cape,"  Official  Handbook  to  the 
Colonial  Exhibition.  History,  Productions,  and  Resources  of  the  Cape  of 
Good  Hope.  Cape  Town,  1886,  p.  178. 

t  Winchell,  Twentieth  Annual  Report  of  the  GeoL  and  Nat.  Hist.  Survey  of 
Minnesota,  p.  157.  Minneapolis,  1893. 

$  Statisque  de  V  Industrie  Miner  ale  en  France  pour  I'annee  1886.  Paris, 
1888,  p.  252. 

§  Ledoux,  "  The  Phosphate  Beds  of  Florida,"  Eng.  Min.  Jour.,  vol.  xlix. 
(1890),  p.  176. 

||  Becker,  "  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope," 
Monographs  of  the  U.S.  GeoL  /Survey,  vol.  xiii.  p.  10.  Washington,  1888. 

^f  Chism,  "  The  Catorce  Mining  District,"  Eng.  Min.  Jour. ,  vol.  xlviii 
(1889),  p.  340. 


PROSPECTING.  95 

and  three  years  later  another  man  pulled  up  a  bush  to  throw 
upon  his  fire,  and  found  native  silver  in  the  roots.  Mining  soon 
began,  and  between  1779  and  1812  the  district  yielded  ore  worth 
from  thirty  to  forty  million  pounds  sterling.  Tradition  relates 
that  the  famous  silver  mines  of  Potosi,  in  Bolivia,  were  dis- 
covered in  a  similar  manner  in  1538,  by  the  accidental  displace- 
ment of  a  bush  which  had  small  lumps  of  native  silver  among  the 
roots. 

The  existence  of  silver  in  the  Province  of  Famatina,  in  the 
Argentine  Republic,*  was  made  known  by  a  pure  accident.  Leita 
and  Echavarria  were  making  a  journey,  in  181 1,  across  the  Andes, 
and  during  a  terrible  storm,  took  refuge  in  a  cave,  and  there 
passed  the  night.  In  the  morning  they  found  that  the  stones 
they  had  put  round  the  fire  at  night  were  white,  and  on  further 
examination  silver  was  plainly  to  be  seen  in  them. 

Adventitious  Finds. — Search  for  one  mineral  often  leads  to 
the  discovery  of  another.  The  working  of  veins  for  tin  ore  has 
revealed  the  presence  of  the  decomposed  granite  which  furnishes 
china  clay. 

The  finders  of  the  Comstockt  lode  worked  it  at  first  for  gold, 
being  quite  ignorant  of  the  presence  of  rich  silver  ore. 

In  the  winter  of  1858-59,  some  prospectors  washed  a  panful  of 
earth  from  a  broad-topped  mound  which  one  of  them  had 
noticed  previously.  This  gave  gold  to  the  value  of  fifteen  cents, 
a  high  average  return.  They  then  noticed  a  gopher  hole  in  the 
mound,  and  took  up  the  earth  which  had  been  thrown  up.  This 
they  washed,  with  satisfactory  results,  and  at  once  staked  out 
claims.  Another  part  of  the  lode  was  discovered  by  some  other 
prospectors,  who  had  dug  a  hole  in  order  to  make  a  little  reservoir 
for  water.  They  chanced  to  wash  some  of  the  earth,  and  to  their 
surprise  found  it  rich  in  gold.  The  upper  part  (back)  of  the  lode 
was  then  worked  for  this  metal.  They  threw  away  bits  of  a  black 
rock  which  they  found  mixed  with  the  earth  and  yellow  sand, 
and  when,  at  a  depth  of  3  or  4  feet,  they  came  upon  a  vein  of  the 
black  mineral,  they  had  not  the  least  idea  that  it  was  valuable. 
Pieces,  however,  were  carried  away  by  curious  visitors,  and  one 
was  given  to  Mr.  Melville  Attwood  for  assay.  He  discovered 
that  it  was  worth  $3,000  per  ton  for  silver  and  $876  for  gold. 
The  black  mineral  was  sulphide  of  silver,  and  the  yellow  sand 
proved  to  be  the  chloride.  The  working  of  the  Comstock 
lode  for  silver  dates  from  this  discovery,  which  was  in  June  1859. 

There  are  reasons  for  supposing  that  the  original  discoverers 
of  the  Comstock  lode  were  two  brothers  named  Grosh  who  had 
found  a  rich  vein  of  silver  in  1856.  But  one  brother  died  from 

*  Hoskold,  La  Republique  Argentine,  p.  19. 

f  Lord,  "  Comstock  Mining  and  Miners,"  Monographs  of  the   U.S.  Geol. 
Survey,  vol.  iv.  pp.  34-55- 
J  Op.  cit.  pp.  27-31. 


96  ORE  AND  STONE-MINING. 

the  effects  of  a  slight  accident,  and  the  other  soon  after  succumbed 
under  the  hardships  he  had  undergone  in  crossing  the  snows  of 
the  Sierras  in  December  1857.  The  knowledge  of  this  vein  was 
then  lost  for  a  time. 

In  1885*  some  natives  or  Spaniards  took  to  M.  Bastide  speci- 
mens of  what  they  thought  was  calarnine  from  the  top  of  Djebel 
Toumai'-Kebir,  Department  of  Oran,  Algeria.  It  turned  out  to 
be  phosphate  of  lime. 

"When  boring  for  rock  salt  in  1839  near  Stassfurt,t  the 
Prussian  Government  found  brine  with  chloride  of  magnesium 
and  chloride  of  potassium.  Later,  in  1852,  they  sank  two  shafts 
through  the  beds  containing  these  minerals,  without  in  any  way 
recognising  their  value,  in  order  to  work  the  rock-salt  underneath. 
However,  it  was  not  long  before  this  mistake  was  corrected,  and 
the  potassium  salts  soon  became  the  main  object  of  the  mining. 

The  sub-wealden  bore-hole  near  Battle,  which  was  put  down 
for  general  information  concerning  the  underlying  strata,  met 
unexpectedly  with  a  bed  of  gypsum,  which  is  now  regularly 
mined. 

The  bed  of  salt  in  the  Cleveland  district  was  discovered  in  1863 
by  a  boring  made  for  the  purpose  of  getting  water.  The  total  area 
now  proved  is  20  square  miles ;  and  if  the  approximate  average 
thickness  of  the  bed  is  taken  at  only  90  feet,  it  may  be  estimated 
to  contain  115,200,000  tons  of  salt  per  square  mile.+ 

A  bore-hole  was  put  down  in  Louisiana  near  Lake  Charles  on 
the  New  Orleans-Texas  Railway  in  search  of  petroleum, §  and  a 
rich  bed  of  sulphur-bearing  rock,  100  feet  (30  m.)  thick,  was 
pierced  unexpectedly.  Owing  to  the  watery  .nature  of  some  of 
the  strata  by  which  it  is  overlain,  it  has  not  yet  been  worked. 

According  to  a  statement  issued  by  the  Broken  Hill  Proprietary 
Company,  Limited,  ||  the  original  claims  of  this  productive  silver 
mine  were  pegged  off  under  the  impression  that  the  outcrop  was 
that  of  a  tin  lode. 

The  Sulphur  Bank^f  in  California  was  originally  worked  for 
sulphur,  and  the  fact  of  there  being  quicksilver  was  long 
unsuspected. 

Instances  of  valuable  minerals  passing  unrecognised  are 
common. 

It  is  related  that  the  original  proprietor  of  the  site  of  Mount 

*  Statistique  de  VIndustrie  minerale  en  France,  pour  I'anme  1886.  Paris, 
1888,  p.  285. 

t  Filhrer  zum  vierten  allgemeinen  Deutschen,  Bergmannstag.iSSg.  Halle 
a.d.  Saale,  1889,  p.  xxxiii. 

£  Marley,  "  On  the  Cleveland  and  South  Durham  Salt  Industry,"  Trans. 
Fed.  Inst.  Af.E.,  vol.  i.  (1889-90),  p.  342. 

§  Hivista  del  Servizio  Miner  ario,  1888,  p.  clxxxiii. 

||  Report  and  Statement  of  Accounts  for  Half-year  ending  November  30, 
1886.  Melbourne,  Victoria,  1886,  p.  57. 

1"  Becker,  op.  cit.  p.  10. 


PROSPECTING. 


97 


Morgan  gold*  mine  used  to  sell  some  of  the  auriferous  stone, 
which  resembles  pumice,  as  hearthstone  for  cleaning  doorsteps. 

Geology  as  a  Guide  to  Minerals. — A  knowledge  of 
geology  will  often  serve  to  guide  the  miner.  Coal  has  been 
discovered  in  the  south-east  of  England  by  very  careful  reasoning, 
based  upon  the  geological  structure  of  South  Wales  and  Somer- 
setshire on  the  west  and  that  of  Northern  France  and  Belgium  on 
the  east. 

M.  Meugy,f  Inspector-General  of  Mines,  hearing  of  the  dis- 
covery of  phosphate  of  lime  in  the  Lower  Greensand  of  England, 
concluded  that  similar  deposits  might  occur  in  the  Cretaceous 
rocks  of  France.  Search  was  made,  and  valuable  deposits  were 
found  in  1852. 

Geology  also  affords  the  miner  aid  by  enabling  him  to  identify 
certain  horizons  in  stratified  rocks  by  their  fossils.  The  valuable 
bed  itself  may  not  always  be  fossiliferous,  but  definite  horizons 
above  or  below  it  may  be  recognisable,  and  so  guide  the  miner  in 
his  explorations. 

Associated.  Minerals. — The  existence  of  valuable  minerals  may 
be  suspected  from  meeting  with  some  of  their  common  associates, 
and,  even  for  the  sake  of  its  importance  to  the  prospector,  the 
subject  of  the  paragenesis  of  minerals  deserves  careful  study. 

The  facts  are  specially  marked  in  the  case  of  tin  ore.  Cassit- 
erite  is  usually  associated  with  minerals  containing  boron  and 
fluorine,  such  as  tourmaline,  topaz,  fluor-spar  and  lithia  mica, 
and  also  with  wolfram,  chlorite,  and  arsenical  pyrites ;  masses  of 
magnetic  iron  ore  are  frequently  accompanied  by  rocks  containing 
garnets,  hornblende,  and  epidote. 

Zinc  blende  is  a  common  hanger-on  of  galena,  which  likewise 
often  has  barytes  in  its  train.  Galena  invariably  contains  silver, 
and  frequently  enough  to  enhance  its  value. 

The  associates  of  gold  in  quartz  veins  are  various  metallic 
sulphides,  such  as  iron  pyrites,  magnetic  pyrites,  copper  pyrites, 
mispickel,  galena,  zinc  blende,  stibnite,  tetradymite,  and  bis- 
muthine. 

Salt  is  accompanied  by  gypsum  and  anhydrite,  and  frequently 
has  its  habitat  in  red  rocks.  Mottura  explains  this  by  pointing 
out  that  when  sea  water  is  evaporated,  the  first  precipitate  is  oxide 
of  iron,  that  gypsum  crystallises  out  next,  and  later  the  sodic 
chloride. 

S  HBP  ACE  INDICATIONS.— The  indications  which  guide 
the  prospector  are  precisely  those  upon  which  the  geological  sur- 
veyor depends  in  making  his  maps,  viz.,  form  of  the  ground,  colour, 
nature  of  the  decomposed  outcrop,  ordinary  springs,  mineral 
springs,  indicative  plants,  altered  vegetation,  burrows  of  animals, 
old  workings,  slag  heaps,  ruins,  names  of  places  and  old  records. 

*  W.  H.  Dick,  A  Mountain  of  Gold.    Brisbane,  1889,  p.  11. 
f  Stat.  Min.  France,  1886.     Paris,  1888,  p.  280. 

G 


98  ORE  AND  STONE-MINING. 

Form  of  the  Ground. — If  the  valuable  mineral  is  harder  or 
softer  than  the  surrounding  rocks,  it  will  affect  the  manner  in 
which  the  surface  is  sculptured  by  atmospheric  agencies.  Hard 
rocks  will  project  in  some  way,  soft  ones  will  be  cut  into  hollows, 
especially  if  they  are  impermeable.  The  outcrop  of  a  hard  bed  will 
be  denoted  by  a  steep  face  or  escarpment,  and  unyielding  mineral 
veins  project  above  the  surface  in  the  form  of  huge  crags  (Fig.  89). 

In  parts  of  our  country,  these  out- 
FIG.  89.  crops   have  been  worked  away  and 

are  no  longer  apparent ;  but  lode- 
quartz  blanched  by  weathering  may 
often  be  seen  standing  up  several 
feet  above  the  surface  on  the  Welsh 
hills,  and  the  run  of  some  lodes  can 
be  traced  for  a  long  distance  by  a 
succession  of  such  outcrops. 

In  the  United  States  and  in  Australia  this  phenomenon  is 
common. 

At  the  Great  Western  Quicksilver  Mine*  in  California,  the 
outcrop  of  the  vein  appears  as  a  dike  over  100  feet  wide,  and 
having  precipitous  sides  in  places  75  feet  high. 

Some  of  the  silver  veins  of  Butte,  Montana,  crop  out,  according 
to  vom  Rath,f  as  great  wall-like  ridges  of  brown  and  black  rock, 
which  is  quartz  containing  the  oxides  of  iron  and  manganese  ;  the 
Rainbow  lode  stood  up  20  feet  above  the  surface. 

The  Broken  Hill  lode  at  Silverton,  New  South  Wales,  was 
traceable  for  fourteen  miles  by  the  outcrop  of  huge  black  crags 
consisting  of  ferruginous  quartz,  brown  ironstone,  pyrolusite  and 
other  minerals,  which  in  places  rose  to  a  height  of  50  feet  above 
the  ground,  and  were  10  to  120  feet  wide. 

Speaking  of  the  outcrops  of  gold  veins  of  the  Hodgkinson  gold- 
field  of  Queensland,  Mr.  R.  L.  Jack,J  the  government  geologist, 
says,  "  they  can  be  followed  from  hill  top  to  hill  top,  forming  at 
times  insurmountable  walls  a  hundred  feet  high ;  as,  for  example, 
in  the  peaks  west  of  Mount  Tenison  Woods.  In  other  places 
denudation  has  left  their  remains  on  hill  sides  or  hill  tops  in  the 
form  of  huge  cubes  of  quartzite,  from  which  the  surrounding  soft 
rocks  have  crumbled  away.  These  cubes  stand  up  weird  and 
solitary,  like  the  *  perched  blocks '  of  Alpine  and  Arctic  lands." 

The  tin  lodes  of  San  Jacinto  in  California  are  found  in  a 
country  destitute  of  all  vegetation  except  grass,  and  their  black 
outcrops  are  said  to  be  unusually  distinct. § 

*  Luther  Wagoner,  "  The  Geology  of  the  Quicksilver  Mines  of  California," 
Eng.  Min.  Jour.,  vol.  xxxiv.  (1882),  p.  334. 

f  Neues  Jahrb.  f.  Miner.,  Geol,  u.  Palaontologie,  1885,  p.  162. 

J  Handbook  of  Queensland  Geology.     London,  1886,  p.  27. 

§  Benedict,  "The  San  Jacinto  Tin  Mines,"  Eng.  Min.  Jour.,  vol.  1.  (1890), 
p.  452. 


PROSPECTING.  99 

The  Great  Quartz  Vein  of  California  has  "a  very  conspicuous 
outcrop,  forming  the  crest  of  the  hills,  so  that  it  can  be  readily 
seen  from  a  distance  of  several  miles."* 

The  "  main  reef  "  of  auriferous  conglomerate  at  Johannesburg, 
in  the  Transvaal,  could  be  traced  in  places  by  the  pebbles  on 
the  surface. 

Soft  minerals  like  clay  offer  less  resistance  to  rain,  flood,  and 
frost,  are  more  deeply  cut  into,  and  give  rise  to  hollows.  Thus 
the  bed  of  clay  known  as  the  Gault,  occupies  a  depression  between 
the  hard  and  pervious  beds  of  the  Chalk  and  the  Lower  Greensand. 

The  presence  of  the  masses  of  decomposed  granite  which  fur- 
nish china  clay  t  is  almost  always  indicated  by  a  slight  depression 
of  the  surface. 

The  ore  bodies  in  the  Sierra  Mojada,  Mexico,  are  softer  than 
the  enclosing  rocks,  which  often  stand  out  when  the  ore  has  been 
worn  away  by  weathering.* 

Colour. — Colour  is  an  important  factor  in  the  discovery  of 
mineral  deposits.  Sometimes  the  ore  itself  has  a  distinct  hue. 
When  Gamier  was  exploring  New  Caledonia  in  1863,  he  was 
struck  by  the  special  green  colour  of  the  rocks,  and  he  found 
that  it  was  due  to  coatings,  veins,  and  lumps  of  a  hydrous  silicate 
of  nickel  and  magnesium,  which  is  now  largely  worked. 

Copper  minerals  will  produce  green,  blue,  and  red  stains, 
which  catch  the  attention  very  quickly.  Iron  gives  a  red  or 
brown  colour,  manganese  a  black ;  lead  may  furnish  a  green,  a 
yellow,  or  a  white  coating,  cobalt  a  pink  one,  whilst  cinnabar  is 
the  natural  vermilion.  Coloured  minerals  are  often  used  as  pig- 
ments by  savages,  and  in  this  way  may  be  brought  to  the  know- 
ledge of  the  explorer. 

Gozzan. — A  mineral  deposit  near  the  surface  is  frequently  so 
altered  by  atmospheric  agencies  that  it  bears  little  resemblance  to 
the  undecomposed  bed  or  vein  which  will  eventually  be  met  with  at 
a  greater  depth.  A  bed  of  hard  shale  will  crop  out  at  the  surface 
as  a  soft  clay  ;  but  the  most  common  cases  of  change  are  furnished 
by  the  conversion  of  sulphides  into  oxides  or  oxidised  compounds, 
and  the  removal  of  some  of  the  mineral  in  the  form  of  a  soluble 
sulphate.  Thus  iron  pyrites,  which  is  such  a  frequent  constituent 
of  mineral  veins,  is  converted  into  hydrated  oxide  of  iron,  and  a 
vein,  originally  consisting  of  iron  pyrites  and  quartz,  becomes  a 
honeycombed  brown  and  yellow  rock,  the  removal  of  the  iron 
pyrites  in  the  form  of  a  soluble  sulphate  leaving  cavities  which 
are  only  partly  filled  up  by  oxide.  The  ferruginous  solutions 
which  flow  away  stain  and  discolour  the  adjacent  rock. 

*  Whitney,  The  Auriferous  Gravels  of  the  Sierra  Nevada  of  California. 
Cambridge,  U.S.,  1880,  p.  46. 

t  J.  H.  Collins,  "The  Hensbarrow  Granite  District."     Truro,  1878,  p.  7. 

±  Chism,  "  Ore  Deposits  of  Sierra  Mojada,"  Trans.  Am.  Inst.  M.E.,  vol. 
xv.  (1886-87),  P-  549- 


ioo  ORE  AND  STONE-MINING. 

The  ferruginous  outcrop  of  mineral  veins  has  been  noticed  in 
all  mining  countries.  In  Cornwall  it  is  called  gozzan,  and  this 
term  has  been  carried  by  the  ubiquitous  Cornish  miner  to  other 
English-speaking  countries,  though  in  Australia  we  hear  of  iron- 
stone blows. 

In  Germany  the  iron  hat  gives  the  proverb — 

Es  ist  kein  Bergwerk  nie  so  gut, 
Es  hat  denn  einen  eisern  Hut ; 

translated  by  the  late  Sir  Warington  Smyth  as  follows — 

"  A  lode  will  ne'er  cut  rich  and  fat, 
Unless  it  have  an  "  iron  hat." 

In  France  the  chapeau  en  far  is  the  equivalent  of  the  German 
expression,  whilst  the  Italian  miner,  ascribing  the  cindery,  burnt- 
up  appearance  to  the  action  of  fire,  calls  such  outcrops  bruccioni.* 
The  Spanish  term  colorados  has  reference  to  the  red  tint  due  to 
iron  oxides.  In  some  parts  of  South  America,  such  as  the 
Argentine  Republic  and  Bolivia,  the  word  pacos  is  used  for  the 
oxidised  ores. 

The  nature  of  a  gozzan  varies  naturally  very  greatly,  not  only 
in  different  districts,  but  also  in  different  parts  of  the  same  lode. 
If  the  vein  originally  consisted  very  largely  of  iron  pyrites,  the 
gozzan  will  be  mainly  ochre  and  brown  iron  ore,  often  in  botry- 
oidal  and  stalactitic  forms.  If  quartz  was  present  also,  a  cellular, 
cindery,  cavernous,  ferruginous  rock  is  the  result  of  the  atmos- 
pheric weathering. 

Other  metallic  minerals  will  leave  their  traces.  Galena  be- 
comes changed  into  anglesite,  cerussite,  pyromorphite,  and  mime- 
tite.  The  sulphides  of  copper  yield  native  copper,  melaconite, 
cuprite,  malachite,  chessylite,  together  with  phosphates,  arseniates, 
and  silicate  of  the  metal,  and  sometimes  the  oxychloride  or  oxy- 
sulphide.  Carbonate  of  manganese  gives  rise  to  black  oxides,  whilst 
argentiferous  minerals  furnish  native  silver,  kerargyrite  and 
embolite. 

Gold  is  unlocked  from  enveloping  sulphides,  and  specimens  of 
quartz  may  be  seen  from  nearly  every  gold-field  in  which  cubical 
cavities,  left  by  the  removal  of  iron  pyrites,  are  partly  filled  up 
with  ochre  and  delicate  skeletons  of  the  precious  metal.  Gold 
may  exist  in  combination  with  other  elements  and  be  liberated 
by  the  weathering  process. 

The  depth  to  which  the  oxidising  and  leaching  action  proceeds 
is  often  considerable.  In  the  Comstock  lode  f  "  the  quartz  is 
reddened  and  the  iron  minerals  more  or  less  oxidised  to  a  depth 
of  500  feet,  but  it  is  probable  that  the  lower  ioo  feet  are  chiefly 

*  Zoppetti,  Arte  Mineraria.     Milan,  1882,  p.  85. 

t  Hague,  Mining  Industry  of  the  Fortieth  Parallel.  Washington,  1870, 
P- 75- 


PROSPECTING. 


101 


coloured  by  the  percolation  of  the  surface  waters."  Sometimes 
there  is  a  sharp  line  of  demarcation,  sometimes  a  gradual  passage, 
between  the  gozzan  and  the  sulphides. 

In  the  sections  of  a  mineral  vein,  Figs.  90  and  91,  A,  is  the 
gozzan,  showing  itself  occasionally  by  rough  crags  at  the  surface ; 
C,  represents  the  undecomposed  sulphides,  and  B  is  an  interme- 
diate zone  where  the  process  of  alteration  is  incomplete.  At 
Huanchaca  silver  mine,  Bolivia,  the  oxidised  ores  near  the  sur- 
face are  called  pacos,  the  transition  oxysulphides  mulatos,  whilst 
the  unchanged  sulphides  are  known  as  metales  frios.  In  the 
longitudinal  section,  Fig.  91,  the  alteration  is  shown  as  ceasing 


FIG.  90. 


FIG.  91. 


soon  after  the  level  of  the  bottom  of  the  valley  is  reached,  that 
is  to  say  when  the  water  no  longer  has  an  easy  exit ;  but  cir- 
cumstances may  bring  about  a  system  of  circulation  causing  the 
rainwater  to  penetrate  below  this  level,  and  then  the  gozzan  will 
naturally  extend  to  a  greater  depth. 

Gozzan  is  important  to  the  miner  not  only  because  it  is  an 
indication  of  a  lode,  but  also  because  the  ore  is  sometimes  more 
valuable  from  the  decomposition  of  the  sulphides.  This  is 
specially  the  case  with  gold  and  silver.  Gold,  as  already  explained, 
is  set  free  from  a  tight  covering  of  pyrites,  or  possibly  from  a  state 
of  combination  with  some  other  element,  and  can  now  be  easily 
caught  by  quicksilver.  The  miner  speaks  of  the  ore  as  "  free- 
milling  "  on  this  account.  Silver,  when  brought  into  the  native 
state,  or  converted  into  chloride,  is  likewise  readily  extracted  by 
amalgamation. 

In  the  case  of  argentiferous  lead  veins,  chloride  of  silver  mixed 
with  carbonate  of  lead  and  oxide  of  iron  is. more  acceptable  to 
the  smelter  than  a  complex  mass  of  metallic  sulphides.  The 
removal  of  zinc  blende  by  atmospheric  agencies,  no  doubt  through 
its  conversion  into  a  soluble  sulphate,  is  of  much  importance; 
for  the  ore  is  thus  freed  from  an  ingredient  which  gives  trouble 
in  the  lead  furnaces,  and  which  cannot  be  satisfactorily  separated 
mechanically  when  very  intimately  mixed  with  galena,  iron 
pyrites  and  other  sulphides.  Furthermore  the  removal  of  some 


io2  ORE  AND  STONE-MINING. 

of  the  heavy  worthless  ingredients,  whilst  the  silver  remains 
fixed  as  insoluble  chloride,  raises  the  tenour  of  the  ore  in 
the  precious  metal.  Lastly,  the  upper  parts  of  the  vein  are 
more  cheaply  worked  from  their  softness,  and  the  small  cost 
of  pumping  and  winding.  Under  these  circumstances  the  fact 
of  a  mine  sometimes  becoming  less  profitable,  or  wholly  un- 
profitable, when  the  zone  of  sulphides  is  reached  will  easily  be 
understood. 

These  points  must  not  fail  to  be  considered  by  the  miner  ;  he 
must  recollect  that  the  zone  of  the  oxidised  ores  will  be  succeeded 
by  sulphides,  more  costly  to  work,  and  sometimes  requiring 
totally  different  treatment. 

Gozzans  should  be  carefully  assayed,  especially  for  silver. 
Instances  could  be  given  of  gozzans  having  been  stamped  and 
worked  for  gold,  to  the  utter  neglect  of  the  silver  which  was  by 
far  the  more  valuable  ingredient. 

In  Cornwall  gozzans  of  copper  lodes  have  been  worked  for  tin 
ore,  which  was  originally  enclosed  in  or  mixed  with  copper  and 
iron  pyrites.  Owing  to  its  insolubility  it  resisted  the  weathering 
which  carried  away  the  copper  and  some  of  the  iron  in  solution. 

The  Anaconda  mine*  at  Butte,  Montana,  now  famous  for  its 
enormous  output  of  copper,  was  originally  bought  as  a  silver 
mine.  For  a  depth  of  400  feet  the  ores  contained  no  notable 
quantity  of  copper ;  this  metal  had  been  carried  off  in  solution, 
whilst  the  silver,  converted  into  an  insoluble  chloride,  was 
rendered  proof  against  any  further  action  of  rainwater. 

Deposits  of  cupreous  iron  pyrites  may  have  the  copper  and 
sulphur  so  completely  removed  that  the  remaining  oxide  of  iron 
is  worked  as  an  ore  of  this  metal.f 

The  iron  ores  of  Bilbao  are  the  decomposed  portions  of  deposits 
of  the  carbonate.  The  weathering  has  had  two  useful  effects ; 
it  has  raised  the  percentage  of  iron,  and  it  has  lowered  the 
amount  of  sulphur  by  decomposing  the  iron  pyrites,  which  occurs 
in  small  quantities  in  the  unaltered  ore. 

The  seams  containing  native  sulphur  in  Sicily  often  show  no 
trace  of  that  element  at  the  surface,  as  the  sulphur-bearing 
limestone  weathers  into  a  soft,  white,  grey,  or  yellowish  white, 
granular  or  pulverulent  variety  of  gypsum,  called  briscale$ 
by  the  miners,  and  considered  by  them  to  afford  important 
indications  concerning  the  bed  itself.  In  this  case  the  sulphur 
has  gradually  become  oxidised  and  has  combined  with  some  of 

*  Douglas,  "The  Copper  Eesources  of  the  United  States,"  Trans.  Amer. 
Inst.  M.K.,  vol.  xix.  (1890-91),  p.  679. 

t  Moxham,  "The  'Great  Gossan  Lead'  of  Virginia/'  Trans.  Amer.  Inst. 
31.fi.,  vol.  xxi.  (1892),  p.  134. 

£  Lorenzo  Parodi,  Suit'  estrazione  detto  Solfo  in  Sicilia.  Florence,  1873, 
pp.  7,  24  :  and  L.  Baldacci,  Descrizione  geoloyica  dclV  Isoki  di  Sicilia. 
Home.  1886  p.  106. 


PROSPECTING.  103 

the  lime  to  form  a  sulphate ;  and  it  is  only  natural  to  suppose 
that  the  thicker  and  the  richer  the  original  bed  was,  the  greater 
will  be  the  amount  of  briscale  produced,  and  the  more  apparent 
its  signs  on  the  surface. 

Each  mineral  therefore  has  to  be  considered  separately,  and  I 
may  mention  a  few  other  special  cases. 

Veins  of  asbestos  have  been  discovered  by  noticing  a  white 
powdery  substance  in  cracks  in  the  rocks,  which  led  to  fibrous 
asbestos  when  worked. 

Steam-puffs  are  indications  of  the  small  superficial  deposits  of 
sulphur  in  volcanic  districts ;  and  here  sight  is  aided  by  the  sense 
of  smell,  for  I  recollect  remarking  the  odour  of  sulphuretted 
hydrogen  long  before  I  rode  up  to  some  sulphur  banks  in 
Iceland.  In  Tuscany  the  natural  steam-puffs  which  yield  boracic 
acid  are  plainly  visible,  and  bore-holes  *  are  also  put  down  to 
produce  them  artificially  where  the  rocks  are  hot  at  the  surface, 
and  so  give  hopes  of  tapping  vapour  at  a  shallow  depth. 

Some  of  the  successful  bore-holes  for  carbonic  acid  gas  in  the 
Eifel,  Germany,  were  planned  on  account  of  natural  emanations 
of  the  gas  in  the  immediate  vicinity. 

Attention  has  been  directed  to  petroleum  by  a  layer  or  an 
iridescent  film  of  the  oil  upon  pools  of  water,  and  the  odour  is 
sometimes  perceptible  for  a  long  distance.  Off  Baku,  on  the 
Caspian,  even  the  sea  is  sometimes  covered  with  an  oily  film  of 
petroleum. 

Brine  springs  point  to  salt,  chalybeate  springs  to  iron,  but  not 
necessarily  to  deposits  of  any  commercial  value ;  the  same  may 
be  said  of  water  impregnated  with  sulphuretted  hydrogen  as  an 
indication  of  native  sulphur.  Springs  of  ordinary  water  may  be 
expected  to  appear  where  a  pervious  bed  rests  upon  an  imper- 
vious one,  so  that  the  outcrop  of  a  bed  of  clay  under  sandstone 
is  often  denoted  by  a  succession  of  springs,  in  addition  to  the 
change  in  the  form  of  the  ground. 

•  Even  when  the  valuable  deposit  presents  no  striking  outcrop, 
it  may  be  followed  by  observing  some  more  marked  attendant. 
Thus  the  "  red  bar  "f  of  the  Johannesburg  district,  is  a  bed  of 
dark  red  slate  which  is  seen  protruding  above  the  surface,  a  little 
to  the  north  of  the  gold-bearing  conglomerate,  for  a  distance  of 
20  miles  along  the  strike. 

In  California  £  a  dark  opaline  or  chalcedonic  rock,  known  to 
the  miners  as  "  quicksilver  rock,"  is  associated  with  the  deposits 
of  cinnabar,  and  owing  to  its  comparative  hardness  stands  out 
sometimes  as  a  projecting  outcrop. 

Indicative  Plants. — As  plants  derive  part  of  their  nourish- 

*  Jervis,  1  tesori  sotterranei  dell'  Italia,  vol.  ii.  p.  428. 
t  Quart.  Jour.  Geol.  /S'oc.,  vol.  xlvi.  (1890),  Proceedings,  p.  4. 
J  Becker,  «'  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope, 
Monograph  of  the  U.S.  Geol.  /Survey,  vol.  xiii.  p.  360.     Washington,  1888. 


io4  ORE  AND  STONE-MINING. 

ment  from  their  roots,  and  as  different  plants  require  different 
foods,  it  is  only  natural  to  suppose  that  a  change  of  soil  causes  a 
change  in  the  vegetation. 

Beds  of  porous  limestone  let  the  rain  soak  down  at  once,  the  soil 
is  shallow,  and  the  foothold  for  trees  is  not  so  good  as  in  the 
case  of  clays.  Thus  the  chalk  hills  are  bare,  and  the  Weald  clay 
is  the  home  of  the  oak  from  a  mechanical  reason,  in  addition  to 
the  chemical  one  of  nourishment. 

Clays  will  retain  water  and  naturally  be  the  habitat  of  rushes 
and  other  moisture-loving  plants. 

The  effect  of  salt  in  the  rocks  is  especially  marked,  and 
Gatzschmann*  gives  a  long  list  of  plants  which  either  flourish  best 
when  getting  salt,  or  cannot  exist  without  it. 

The  flora  of  Monte  Catini,f  in  the  province  of  Lucca,  well 
known  for  its  brine  baths,  resembles  that  of  the  coast,  although 
24  miles  away  from  the  sea,  and  separated  from  it  by  the  Pisan 
Hills. 

My  friend,  Mr.  S.  Herbert  Cox,  tells  me  that  the  run  of  the 
deposit  of  alunite  which  he  is  working  in  New  South  Wales,  is 
marked  by  a  lighter  green  in  the  colour  of  the  leaves  of  the 
eucalyptus  trees  which  cover  the  district.  He  has  also  noticed 
in  New  Zealand  that  the  Karacca  trees  growing  upon  limestone 
have  darker  leaves  than  those  growing  upon  slate.  A  band  of 
limestone  can  be  traced  in  this  way. 

The  subject  of  indicative  plants  is  dealt  with  in  an  interesting 
paper  by  Raymond,!  who  gives  some  additional  details  concerning 
the  calamine  pansyof  Rhenish  Prussia,  mentioned  by  Gatzschmann. 
This  pansy,  called  by  botanists  Viola  calaminaria,  is  peculiar  to 
the  calamine-bearing  hills  near  Aix-la-Chapelle,  and  in  West- 
phalia. The  blossoms  are  almost  always  yellow ;  but  on 
the  borders  of  the  zinc  regions  some  are  light  violet,  or  bluish, 
or  mixed  yellow  and  blue,  and  are  supposed  to  be  hybrids 
between  V.  calaminaria  and  the  ordinary  wild  pansy,  V.  tricolor. 
Analysis  has  revealed  the  presence  of  zinc  in  the  plant 
and  in  the  sap.  This  plant  is  said  to  have  been  recognised  at 
Horn  Silver  Mine  in  Utah,  the  ore  of  which  contains  zinc 
blende. 

The  lead  plant,  Amorpha  canescens,  Nutt.,  is  a  low  shrub,  i  ft. 
to  3  ft.  high,  whitened  with  hoary  down.  The  plant  is  most 
abundant  in  Michigan,  Wisconsin,  and  Illinois,  and  miners 
believe  that  it  flourishes  best  where  lead  ore  exists  in  the  soil. 

Dr.  F.  Stapff  found  that  prospectors  for  phosphorite,  in 
Estremadura  were  guided  by  a  creeping  plant  with  bell-shaped 
flowers,  Convolvulus  althceoides ;  in  Montana  the  Erigonum 

*  Die  Aufsuchung  und  Untersuchung  von  Lagerstatten  nutzbarer  Miner  alien. 
Leipsic,  1866,  p.  321. 

t  Jervis,  Guida  (die  deque  minerali  d'ltalia.     Turin,  1868,  p.  12. 
I  Trans.  Am.  Inst.  M.E.,  vol.  xv.  (1886-87),  p.  647. 


PROSPECTING.  105 

ovali/olium,  Nutt.,  is  looked  upon  as  an  indication  of  silver  ore  in 
the  vicinity. 

Animal's  as  Indicators. — Animals  also  may  occasionally 
render  services  to  the  prospector.  I  have  already  mentioned  the 
case  of  the  wombat,  by  whose  burrows  copper  was  discovered  in 
South  Australia.  Prospectors  seeking  for  tin  lodes  in  Victoria* 
have  also  been  guided  to  success  by  the  ore  thrown  out  from 
decomposed  dykes  by  this  animal.  Ledouxf  says  that  a  useful 
indication  of  phosphate  of  lime  in  Florida  was  furnished  by  ant- 
hills and  gopher  holes,  which  showed  small  whitish  grains  of  the 
mineral  in  the  earth. 

GatzschmannJ  mentions  cases  of  the  discovery  of  valuable  ores 
by  the  scratchings  of  the  beaver,  the  bear,  and  the  marmot,  as 
well  as  by  the  wallowing  of  pigs ;  he  also  brings  forward  in- 
stances in  which  the  first  indications  of  mineral  wealth  were 
afforded  by  stones  kicked  up  by  a  horse,  or  tossed  out  by  a 
bull,  or  lying  in  the  nest  of  a  vulture,  or  found  in  the  crop  of  a 
grouse. 

At  the  Caratal  diggings  in  Venezuela,  a  bird  called  the  minero 
was  thought  to  mark  the  site  of  gold-bearing  gravel.  I  often 
heard  its  notes  when  passing  pits  where  gold  was  being  obtained, 
and  it  is  possible  that  it  preferred  certain  trees  which  grew  upon 
the  old  alluvia.  In  fact,  as  so  many  animals  obtain  their  food 
from  special  plants,  it  is  evident  that  the  fauna  dependent  upon  the 
flora  must  be  affected  indirectly  by  the  minerals  of  the  soil.  The 
special  case  of  there  being  more  genera  and  species  of  snails  in  a 
limestone  country  is  a  case  in  point.  Lastly,  the  tracks  of  animals 
may  lead  to  salt  springs  which  they  frequent. 

Sheading. — The  prospector  seeks  *  for  natural  sections  of  the 
rocks  such  as  occur  in  cliffs,  or  in  river  valleys  and  their  tributary 
gullies  and  gorges.  He  examines  the  materials  constituting  the 
river  beds,  especially  when  the  water  is  low  in  the  dry  season, 
often  digging  up  and  washing  portions  in  a  pan  or  in  a  batea,  in 
order  to  ascertain  whether  they  contain  traces  of  the  heavy  ores 
or  metals. 

If,  while  prospecting  in  a  valley,  he  discovers  stones  that  have 
the  appearance  of  having  once  belonged  to  veins  or  other  valuable 
deposits,  he  endeavours  to  trace  them  to  their  source,  and  is, 
perhaps,  rewarded  by  finding  similar  fragments,  but  less  water- 
worn,  as  he  goes  up  the  stream.  Further  on  he  may  come  upon 
large  blocks  of  veinstuff  lying  about,  and  finally  find  the  veins 
laid  bare  in  a  gorge,  or  at  the  bottom  of  a  brook,  or  possibly  pro- 
jecting above  the  soil  in  the  form  of  huge  crags  of  quartz  in  the 
manner  already  described. 

*  Victoria,  Reports  and  Statistics  of  the  Mining  Department  for  tlie  Quarter 
ended  March  31,  1890,  p.  15.  Melbourne,  1890. 

t  A.  K.  Ledoux,  "  The  Phosphate  Beds  of  Florida,"  Etuj.  Miii.  Jour., 
vol.  xlix.  Feb.  1890,  p.  176.  £  Op.  cit.  p.  311. 


io6  ORE  AND  STONE-MINING. 

Loqse  pieces  of  veinstuff  found  lying  about  on  the  surface  are 
known  in  Cornwall  as  shoad-stones ;  and  sheading  is  the  term 
given  to  the  process  of  tracking  them  to  the  parent  lode. 

If  the  prospector  has  ascertained  the  existence  of  a  lode  by 
shoad-stones,  and  has  some  idea  of  the  position  of  the  outcrop 
which  lies  concealed  under  the  soil,  he  proceeds  to  dig  trenches 
across  the  presumed  line  of  strike,  until  he  hits  upon  the  back 
of  the  lode.  When  the  covering  of  soil  is  too  deep  for  trenching, 
a  little  shaft  is  sunk,  and  a  tunnel  is  driven  out  at  right  angles 
to  the  supposed  course  of  the  vein. 

Loaminy  in  Australia  corresponds  to  sheading.  The  prospector 
washes  earth  from  the  base  and  slope  of  a  hill  till  the  specks 
of  gold  are  pretty  frequent,  and  then  endeavours  to  trace  the  gold 
uphill  to  the  reef  that  furnished  it.  When  he  can  no  longer  get 
gold  by  washing  he  concludes  he  has  gone  past  the  outcrop  of  the 
reef,  and  he  proceeds  to  search  for  it  by  trenching.  Reefs  have 
been  discovered  in  this  way  which  showed  no  surface  indication 
whatever.* 

Hushing.t — Hushing  consists  in  causing  a  stream  of  water 
to  rush  down  a  hillside,  and  cut  a  ditch  through  the  soil,  which 
will  lay  bare  the  outcrops  of  veins,  if  any  exist.  A  reservoir  is 
made  at  some  suitable  spot  on  the  high  ground,  and  a  shallow 
gutter  is  dug  down  the  slope  along  the  line  which  it  is  pro- 
posed the  stream  should  take.  The  water  is  allowed  to  run  down 
gently  at  first,  and  then  as  a  torrent,  which  scours  out  a  trench 
to  the  solid  rock.  An  examination  of  the  trench  and  of  the  stones 
washed  out  of  it  may  result  in  the  discovery  of  a  vein. 

Piercing. — In  some  special  cases  when  the  mineral  lies  very 
near  the  surface,  and  is  either  harder  or  softer  than  the  surround- 
ing rock,  the  searcher  makes  use  of  a  sharp  pointed  steel  rod, 
which  he  thrusts  into  the  ground.  The  well-known  French  J 
burr-stones,  lying  in  soft  sand  and  clay  at  a  depth  of  10  to  18 
feet,  are  found  in  this  way  ;  whilst  in  the  Isle  of  Man  superficial 
pockets  of  umber  in  the  Carboniferous  Limestone  are  detected  by 
the  ease  with  which  the  rod  runs  down. 

Kauri  gum,  a  semi-fossil  resin  of  New  Zealand,  which  occurs  in 
lumps  of  about  the  size  of  a  hen's  egg  a  few  inches  below  the  sur- 
face in  the  high  ground,  and  a  few  feet  in  the  swamps,  is  sought 
for  by  a  similar  tool. 

Mr.  Lawn  informs  me  that  in  the  Furness  district  a  pointed 
iron  rod  is  occasionally  used  in  searching  for  shallow  deposits 
of  haematite,  lying  within  6  or  8  feet  of  the  surface.  The  miner 
examines  the  point  of  the  rod  after  thrusting  it  through  the  thin 

*  "The  Gold-fields  of  Victoria,"  Reports  of  the  Mining  Registrars  for  the 
Quarter  ended  March  31,  1888.  Melbourne,  1888,  p.  68. 

t  Williams,  Natural  History  of  the  Mineral  Kingdom.  Edinburgh,  1789, 
vol.  i.  p.  370. 

+  Gallon,  Lectures  on  Mininy.     London,  1881,  vol.  ii.  p.  41. 


PROSPECTING.  107 

covering  of  soil,  and  if  he  finds  it  to  be  red,  he  concludes  that 
there  is  iron  ore  underneath.  If  the  indications  are  sufficient, 
he  sinks  a  little  pit  and  begins  to  work  the  ore. 

The  valuable  bed  of  phosphatic  nodules  in  South  Carolina  *  is 
much  harder  than  the  overlying  sand  and  clay ;  the  prospector 
carrying  a  steel  rod  works  it  down,  until  he  meets  with  the  resist- 
ing stratum.  He  notes  the  depth,  which  is  under  15  feet,  as 
no  phosphate  is  at  present  worked  deeper  than  that,  and  after 
walking  on  100  feet  further  forces  the  rod  down  again.  By 
thrusting  down  the  rod  at  regular  intervals  in  this  way,  and 
noting  the  results,  he  obtains  a  general  idea  of  the  lie  of  the  phos- 
phate bed,  and  proceeds  to  make  a  more  minute  examination  by 
sinking  exploratory  pits,  10  feet  by  5  feet,  at  intervals  of  500 
feet.  The  phosphate  rock  laid  bare  is  taken  out,  carefully 
sampled  and  analysed,  and  in  this  way  a  very  fair  estimate  can  be 
made  of  the  yield  of  a  given  area. 

The  process  of  testing  a  bed  of  mineral  by  pits  is  sometimes 
carried  out  on  a  very  extensive  scale.  According  to  Winchell 
$60,000  have  been  spent  in  mere  explorations  at  the  Biwabik 
Iron  Mine,f  in  the  Mesabi  Range,  Minnesota  ;  but  in  this  case  the 
pits  were  practically  small  shafts,  many  of  which  exceeded  100 
feet  in  depth. 

Lode-lights. — Appearances  of  flame  above  mineral  veins  are 
said  to  have  been  seen,  and  at  all  events  are  sufficiently  well  estab- 
lished to  have  received  a  special  name,  "  lode-lights,"  in  Cornwall. 
It  is  possible  that  a  will-of-the-wisp  (phosphoretted  hydrogen)  may 
have  been  produced  occasionally  by  the  action  of  organic  matter 
and  water  upon  phosphates,  which  are  so  common  in  the  upper 
parts  of  mineral  veins. 

Marsh-gas  is  known  in  the  workings  of  some  lead  lodes,  and 
may  have  occasionally  issued  in  sufficient  quantity  to  produce 
flame  when  ignited  accidentally. 

Altered  Vegetation  and  other  indications. — One  hears  of 
differences  in  the  appearance  of  the  vegetation  along  the  line  of 
mineral  deposits,  of  places  where  the  snow  will  not  lie  in  the 
winter,  and  of  vapours  hanging  over  the  ground.  Though  some 
writers  refuse  to  put  any  value  on  these  indications,  they  should 
not  be  entirely  overlooked,  because  the  outcrop  of  a  lode,  of 
different  nature  and  texture  to  the  surrounding  rocks,  may  readily 
cause  the  phenomena  just  mentioned.  One  need  only  look  at  the 
rubbish-heaps  of  some  mines,  especially  those  yielding  pyrites, 
which  remain  year  after  year  bare  and  barren,  to  understand  the 
blighting  and  withering  action  of  the  products  of  decomposition  of 
some  minerals  upon  vegetation,  It  is  only  natural  to  suppose  that 

*  Wyatt,  The  Phosphates  of  America.     New  York,  1891,  p.  49. 

t  "The  Biwabik  Mine,"  Trans.  Amer.  lust.  M.E.,  vol.  xxi.,  1892-3, 
p.  951  ;  and  Geol.  and  Nat.  Hist.  Survey  of  Minnesota.  Twentieth  Ann. 
Hep.  for  the  year  1891.  Minneapolis,  1893,  p.  156. 


io8  ORE  AND  STONE-MINING. 

grass  would  grow  less  luxuriantly  upon  a  wide  pyritous  vein  than 
upon  adjacent  slate,  and  that  a  decided  streak  of  altered  colour 
and  growth  would  be  visible  upon  the  turf. 

A  very  simple  experiment  will  convince  the  student  more 
readily  than  the  mere  statement.  Spread  a  thin  layer  of  earth 
upon  a  tray,  and  imitate  the  outcrop  of  a  lode  by  scraping  away 
some  of  the  earth  and  re-placing  it  by  powdered  iron  pyrites  or 
marcasite.  Now  scatter  mustard  seed  over  the  surface,  and 
water  frequently.  In  the  course  of  a  few  days  there  will  be  a 
crop  of  mustard  on  the  earth,  but  the  track  of  the  pyrites  will  be 
marked  by  a  bare  streak  on  which  the  seeds  have  been  killed  by 
sulphate  of  iron  formed  by  its  decomposition. 

The  rapid  disappearance  of  snow  on  the  outcrop  of  a  lode  has 
been  noticed  at  Ducktown  Mine,  Tennessee,*  among  other  places. 
The  oxidation  going  on  in  a  pyritous  lode  near  the  surface  must 
produce  a  certain  amount  cf  heat,  which  would  make  the  outcrop  of 
a  lode  warmer  than  the  adjacent  rock ;  but  one  need  not  have 
recourse  to  this  hypothesis  in  order  to  account  for  phenomena  of 
this  kind.  Mineral  veins  are  often  channels  along  which  under- 
ground waters  circulate  ;  this  water  may  come  near  to  the  surface 
in  places,  or  even  issue  forth  as  a  spring,  and  the  proximity  of 
the  comparatively  warm  water  may  keep  the  outcrop  warm  enough 
not  to  freeze.  In  a  porous  cavernous  gozzan  it  is  easy  to  imagine 
the  existence  of  slow  currents  of  the  air  which  would  have  the 
same  effect. 

The  fact  of  a  vein  often  being  a  channel  of  water  will  also 
explain  the  rising  of  vapours  from  lodes  under  certain  favourable 
conditions  of  the  atmosphere. 

Where  the  surface  is  cultivated  and  the  natural  springs  are 
tapped  by  adit  levels  or  other  mine  workings,  these  appearances 
cannot  be  looked  for  to  any  great  extent ;  and  it  is  not  unlikely 
that  the  old  miners,  who  have  handed  us  down  traditions  con- 
cerning the  signs  of  mineral  veins,  were  keener  observers  of 
nature  than  some  of  their  successors,  just  as  the  savage  may  be 
guided  by  marks  which  do  not  catch  the  eye  of  the  civilised 
traveller. 

Old  Workings,  Slag  Heaps,  Ruins. — Signs  of  old  workings, 
such  as  pits  and  rubbish-heaps,  often  tell  useful  tales.  When 
workings  were  shallow,  miners  put  down  shafts  in  close  proximity, 
and  the  line  of  a  series  of  shafts  and  rubbish-heaps  will  give  a 
fairly  correct  idea  of  the  strike  of  a  lode.  The  rubbish-heaps 
will  show  what  was  the  ore  worked,  and  with  what  it  was  asso- 
ciated. 

It  even  happens  that  mining  refuse,  thrown  away  as  worthless 
in  the  days  when  dressing  appliances  were  crude  and  rough,  will 
pay  for  being  worked  over  again.  On  the  other  hand  it  is  not  safe 

*  Wendt,  "  The  Pyrites  Deposits  of  the  Alleghanies,"  Encj.  Min.  Journ., 
vol.  xli.  (1886),  p.  408. 


PROSPECTING.  109 

to  conclude  that,  because  it  paid  to  work  a  mine  some  centuries 
ago,  the  same  ore  will  yield  a  greater  profit  or  even  be  worth 
working  nowadays.  The  change  in  the  value  of  the  precious 
metals,  and  the  change  in  the  remuneration  of  the  labourer,  must 
be  duly  weighed  before  a  decision  can  be  arrived  at. 

It  is  important  to  ascertain  why  the  old  mines  were  abandoned. 
If  no  good  reason,  such  as  a  sudden  inrush  of  water,  or  the  break- 
ing out  of  a  great  war,  for  instance,  can  be  assigned  for  the  stop- 
page, it  is  usually  safe  to  assume  that  no  great  riches  have  been 
left  in  sight ;  statements  to  the  contrary  must  be  very  carefully 
sifted. 

Minerals  that  were  at  one  time  worthless  or  even  regarded  as 
obnoxious,  such  as  nickel  and  cobalt  ores,  or  zinc  blende,  become 
valuable  by  the  discovery  of  new  or  improved  processes  of  manu- 
facture or  smelting.  An  instance  of  this  kind  has  occurred  quite 
lately.  Some  forty  years  ago  the  outcrops  of  beds  of  impure  car- 
bonate of  manganese  in  North  Wales  were  worked  for  the  black 
oxides,  the  gozzans,  in  fact,  which  had  been  produced  by  the 
weathering  of  the  deposit  near  the  surface.  The  undecomposed 
carbonate  was  at  that  time  of  no  value  and  was  carefully  separated 
by  cobbing  and  rejected ;  and  the  workings  had  to  be  abandoned 
when  the  black  oxide  diminished  in  quantity  at  a  shallow  depth, 
and  was  replaced  by  unweathered  ore.  Owing  to  the  use  of  ferro- 
manganese  in  making  steel,  the  carbonate  can  now  be  utilised, 
and  the  ore  is  regularly  mined  and  sent  to  the  blast  furnaces  to 
be  smelted  with  iron  ore. 

On  the  other  hand  the  discovery  of  a  new  process  may  be  the 
means  of  causing  a  mine  to  be  unprofitable.  The  discovery  by 
Weldon  of  a  method  of  regenerating  the  oxide  of  manganese  used 
in  making  bleaching  powder,  seriously  affected  manganese  mining 
by  lessening  the  demand  for  the  ore. 

Old  mine. plans,  reports,  and  deeds  should  be  consulted  when 
available ;  and  information  should  be  sought  from  official  geological 
surveys  and  mining  records  when  they  exist,  as  they  do  in  this 
country.  A  prospector  told  me  a  few  years  ago  that  he  missed 
securing  some  manganese  properties  in  North  Wales,  from  not 
being  aware  that  a  government  geological  map  of  the  district  had 
been  published,  showing  some  of  the  outcrops  of  the  manganiferous 
bed. 

Slag  heaps  afford  indirect  evidence  of  mining,  and  like  old 
rubbish-heaps  may  occasionally  be  worth  smelting.  The  most 
notable  instance  of  late  years  has  been  the  profitable  treatment 
of  such  heaps  at  Laurium,  in  Greece. 

Ruined  cities,  or  other  indications  of  a  country  having  been  more 
thickly  populated,  are  sometimes  adduced  as  proofs  of  its  mineral 
wealth.  Where  it  is  possible  to  show,  from  remains  found  in  the 
towns  or  encampments,  that  the  inhabitants  were  engaged  in 
mining  or  smelting  operations,  the  prospector  may  fairly  lay  stress 


no  ORE  AND  STONE-MINING. 

upon  evidence  of  this  kind.  It  has  often  been  supposed  that  some 
of  the  old  entrenchments  in  Cornwall  were  made  for  the  protec- 
tion of  diggers  or  smelters  of  alluvial  tin  ore ;  and  after  the  careful 
explorations  of  Mr.  Theodore  Bent  at  Zimbabwe,  in  Mashonaland, 
most  persons  will  be  disposed  to  agree  with  him  that  this  old  city 
and  its  fellows  owed  their  existence  to  gold  mining. 

Names  of  Places. — Local  names  may  sometimes  supply  in- 
formation, either  by  denoting  some  natural  feature  connected  with 
the  deposit,  or  by  recording  in  some  way  the  existence  of  mine  work- 
ings. They  will  be  found  in  all  languages,  and  I  need  only  give  a  few 
instances.  "  Cae  Coch,"  near  Trefriw,  in  Carnarvonshire,  means 
the  "  red  field,"  from  the  chalybeate  springs,  which  are  due  to  the 
existence  of  a  bed  of  iron  pyrites  now  being  worked.  "  Graig 
Goch  "  or  "  red  rock,"  a  name  which  is  not  uncommon  for  mines 
in  Wales,  denotes  no  doubt  that  the  vein  was  discovered  by  a  red 
ferruginous  outcrop,  and  so  does  the  name  "  Fron  Goch  "  or  "  red 
breast."  Red  Mountain,  near  Birmingham,  Alabama,  owes  its 
name  to  the  outcrop  of  an  important  bed  of  iron  ore.  "  Glasdir," 
meaning  "  blue  ground,"  is  the  name  of  a  copper  mine  in  North 
Wales.  I  cannot  help  suspecting  that  the  locality  was  so  called 
in  consequence  of  the  blue  colour  given  to  rocks  or  stones  by 
coppery  minerals  derived  from  chalcopyrite  near  the  surface. 
"  Balmy nhir  "  or  the  "  diggings  at  the  long  stone,"  denotes  work- 
ings for  tin  in  the  neighbourhood  of  a  "  menhir  "  or  erect  stone  in 
Cornwall.  Sometimes  the  substance  is  named,  as  in  the  words 
Tincroft,  Stahlberg  (steel  mountain),  Porto  Ferraio  (iron  port)  in 
Elba,  Gebel  Zeit  (oil  mountain)  on  the  shores  of  the  Red  Sea, 
Yenang-yaung  (Creek  of  oil),  the  site  of  the  petroleum  wells  in 
Burmah.  The  names  Leadhills  (Scotland),  Bleiberg  (Germany), 
and  Gebel-el-Kohol  (Tunis),  all  have  the  same  signification,  and 
have  been  given  from  the  existence  of  workings  for  lead  ore. 
"  Al  maden  "  means  *'  the  mine,"  and  turning  from  Spain  to  our 
own  country,  we  find  "  Minera,"  near  Wrexham,  with  a  similar 
signification  given  in  this  case  by  the  Romans,  instead  of  the 
Moors.  The  Smoky  Mountains,*  in  North  Carolina,  were  called 
by  the  Indians  "  Unaka,"  from  their  word  "  Unakeh,"  meaning 
"  white,"  because  they  obtained  white  kaolin  from  them. 

Salt  is  indicated  by  the  prefix  "  Sal,"  "  Salz,"  or  its  equivalent 
"  Hall,"  in  numerous  names  of  places. 

The  German  word  for  miner,  "Bergmann" — i.e.,  mountain 
man  or  highlander — reminds  us  that  the  old  ore-seekers  were 
hillmen,  and  found  their  treasures  among  the  mountains,  and  we 
constantly  find  the  word  "  Berg  "  (mountain),  or  its  equivalent  in 
other  languages,  forming  part  of  the  names  of  mines  or  mining 
towns.  Schneeberg,  Marienberg,  Freiberg,  in  Saxony,  are 
instances,  and  of  recent  date  we  have  Mount  Morgan  in  Queens- 

*  W.  B.  Phillips,  "Mica  Mining  in  North  Carolina,"  Encj.  Min.  Journ., 
vol.  xlv.  (1888),  p.  398. 


PROSPECTING.  in 

land,  and  Broken  Hill  in  New  South  Wales.  In  the  list  of 
copper  mines  of  South  Australia*  I  find  no  less  than  twenty-six 
names  of  mines  beginning  with  "  Mount,"  in  addition  to  others 
containing  the  word  "  hill "  or  "  knob." 

Other  names  refer  to  mining  or  smelting  operations.  The 
village  of  Pestarena,  near  Monte  Rosa,  was  evidently  so  called 
from  the  crushing  of  gold  ore  in  the  days  of  the  Romans. 
"  Cinderford,"  in  the  Forest  of  Dean,  points  to  old  heaps  of  iron 
slag,  and  such  a  name  as  "  hammer  pond,"  in  the  Weald  of  Kent 
and  Sussex,  likewise  tells  us  of  iron  working  in  days  gone  by.  But 
no  stress  should  belaid  upon  names  ;  they  afford  at  most  an  indica- 
tion of  the  existence  of  a  mineral,  without  any  evidence  of  its 
value  at  the  present  day. 

Divining  Bod. — Belief  in  the  divining  rod,  or  dowsing  rod, 
has  not  died  out  completely  even  in  Cornwall,  where  one  still 

FIG.  92. 


meets  with  educated  persons  who  profess  to  be  able  to  discover 
mineral  veins  by  the  dipping  down  of  the  forked  twig  when  they 
walk  across  them. 

Fig.  92,  reduced  from  Agricola,f  shows  old  German  miners 
searching  for  veins  with  the  rod. 

Dipping  Needle. — In  the  special  case  of  magnetic  iron  we  have 
a  safer  guide.  In  Sweden  a  magnet,  suspended  so  that  it  can  dip 

*  H.  Y.  L.  Brown,  "A  Record  of  the  Mines  of  South  Australia." 
Adelaide,  1890. 

t  De  re  Metallicd,  Basle,  1556,  p.  28  ;  and  Brough,  "  Cantor  Lectures  on 
Mine  Surveying,"  Jour.  Soc.  Arts,  vol.  xl.  (1892),  p.  803. 


112 


ORE  AND  STONE-MINING. 


FIG.  93. 


in  any  direction,  is  regularly  used  for  tracing  masses  of  magnetic 
iron  ore,  even  when  concealed  by  some  thickness  of  drift  or  some 
depth  of  water;  when  the  lakes  are 
frozen  over  in  winter,  this  kind  of  pro- 
specting is  easy. 

The  miner  carries  his  compass  care- 
fully over  the  ground,  and  on  approach- 
ing magnetic  ore  the  needle  dips  towards 
it ;  the  amount  of  dip  increases,  until  at 
last,  when  standing  directly  over  the 
deposit,  the  needle  becomes  vertical,  and 
remains  so  as  long  as  there  is  a  strong 
mass  of  ore  underneath  it.  The  boun- 
dary of  the  deposit  can  thus  be  laid  down 
on  a  map  with  some  degree  of  accuracy. 
The  modification  of  the  Swedish  dipping 
needle  shown  in  Fig.  93,  borrowed  from 
Brough,*  has  been  adopted  in  the  United 
States.  Improved  methods  devised  by 
Brooks,  Thalen,  and  Tiberg  are  described 
by  the  same  author. 

Qualifications  of  the  Prospector. 
— From  the  above  observations  it  will  be 
seen  that  the  miner  is  greatly  aided  in  his 
search  by  a  variety  of  natural  indications ; 

but  in  a  new  and  unsettled  country  the  physical  difficulties  of 
travel  are  often  so  great,  that  strength  of  body  and  the  capability 
of  supporting  fatigue  and  hardships  become  some  of  the  most 
important  qualifications  of  the  prospector.  He  should  have 
a  general  knowledge  of  geology,  and  understand  mineralogy 
sufficiently  to  recognise  all  the  common  and  valuable  minerals 
and  their  ordinary  associates,  and  to  confirm  his  opinion  by 
simple  tests.  The  pick,  shovel,  and  pan  should  be  handled  with 
ease,  as  well  as  the  rifle  and  the  gun.  Keen  and  good  eyesight  is 
a  sine  qua  non ;  a  myopic  prospector  would  fail  to  recognise 
natural  features,  and  a  colour-blind  person  would  not  be  struck 
by  important  differences  of  tint. 

*  The  mode  of  discovering  minerals  by  boring  is  a  subject  of  so 
much  importance  that  it  requires  a  separate  chapter. 

*  A  Treatise  on  Mine  Surveying.     London,  1891,  p.  261. 


CHAPTER   III. 


BOEING. 

Uses  of  bore-holes. — Methods  of  boring  holes: — I.  Boring  by  rotation  ;. 
Auger  ;  Diamond  drills.  — II.  Boring  by  percussion  with  rods  ;  Iron 
rods,  wooden  rods ;  Driven  wells. — III.  Boring  by  percussion  with 
rope;  American  system;  Mather  and  Platt's  system. — Surveying 
bore-holes. 

The  uses  of  bore-holes  are  numerous  : 

'  i.  To  reach  a  mineral  deposit  by  a  small  hole  and  ascertain  its  nature,, 
depth  from  the  surface,  thickness,  dip,  and  strike,  with  the  object 
of  working  it  if  possible. 

2.  To  ascertain  the  nature  of  the  subjacent  rocks  for  engineering  pur- 

poses, such  as  their  suitability  for  railways,  canals,  locks,  sewers,, 
or  foundations  of  bridges  and  buildings. 

3.  To  obtain  liquids,  such  as  ordinary  water,  mineral  water,  brine  or 

petroleum,  which  either  rise  to  the  surface,  or  have  to  be  pumped 
up  from  a  certain  depth. 

4.  To  make  absorbent  wells  in  dry  and  porous  strata. 

5.  To  obtain  gases,  such  as  natural  inflammable  gas,  carbonic  acid  gas, 

or  vapours  containing  boric  acid. 

6.  To  drain  off  gas  from  rocks,  and  water  or  gas  from  mine  workings. 

7.  To  make  passages  for  conveying  power  into  underground  workings 

by  steam,  water,  wire-ropes,  or  electricity. 

8.  To  put  signal  wires  or  speaking  tubes  into  underground  workings. 

9.  To  introduce  cement  into  unsound  foundations  in  order  to  strengthen, 

them,  and  also  into  mine-workings  in  order  to  dam  back  water. 
10.  To  sink  holes  for  lightning  conductors,  house-lifts,  or  piles. 
u.  To  sink  mine  shafts. 

The  methods  of  boring  holes  for  these  purposes  are : 

I.  By  rotation. 
II.  By  percussion,  with  rods. 
III.  By  percussion,  with  ropes. 

I.  BORING  BY  ROTATION.— Auger.— Soft  rocks,  such 
as  clay,  soft  shale,  sandy  clay,  and  sand  can  be  bored  by  an 
open  auger  (Fig.  94),  like  the  well-known  carpenter's  tool. 

The  mode  of  working  consists*  in  twisting  the  tool  round  by 
means  of  a  cross-head  or  spanner,  and  lengthening  it  as  the 
hole  is  deepened.  The  lengthening  rods  are  made  of  wood  or 
iron,  the  iron  ones  being  ij  inch  gas-pipe,  with  screwed  pin 

*  Darley,  "  Artesian  Wells,"  Engineering,  vol.  xxxix.  (1885),  p.  683. 

u 


OKE  AND  STONE-MINING. 


and  box  ends  welded  on.  Even  when  iron  rods  are  used,  some 
made  of  pine,  4  inches  by  4  inches,  are  added  in  order  to  take 
off  part  of  the  heavy  weight  by  their  buoyancy  in  water.  For 
raising  the  rods  an  iron  or  wooden  derrick  is  employed,  such  as  is 


FIG.  94. 


FIG.  95. 


shown  in  the  figure  95.  It  is  30  feet  high,  so  as  to  give  room  for 
pulling  up  a  rod  of  the  usual  length  of  25  feet,  which  is  drawn 
up  by  means  of  a  crab-winch  with  a  i  J  inch  iron  or  steel  wire 
rope.  The  winch  is  worked  by  hand  or  horse-power  as  required. 
The  top  rod  is  made  of  square  iron,  and  the  cross-head  or  capstan 
spanner  can  be  fixed  to  it  at  the  height  most  convenient  for 
handling. 


or  THE 
UNIVERSITT 


n6 


OEE  AND  STONE-MINING. 


FIG.  97. 


The  process  of  boring  consists  in  turning  the  rod  by  two 
men  at  the  capstan  until  the  working  tool  has  filled  itself ;  it  has 
then  to  be  drawn  up  and  emptied.  In  drawing  up,  each  rod  has 
to  be  unscrewed  and  taken  off,  and  the  process  is  reversed  when 
the  tool,  after  having  been  cleaned  out,  is  again  lowered. 

In  favourable  strata  holes  are  bored  400  feet  deep  at  the 
rate  of  25  feet  a  day  by  this  method  ;  it  is  obvious  that,  owing  to 
the  time  occupied  in  raising  and  lowering  the  rods,  the  first 
part  of  the  boring  is  performed  at  a  much  greater  speed  than  the 
last. 

In  order  to  obviate  the  loss  of  time  which  ensues  in  raising  and 
lowering  the  rod,  for  the  purpose  of  extracting  the  contents  of  the 
auger,  a  current  of  water  may  be  sent  down  through  the  hollow 
rod,  and  made  to  ascend  in  the  annular  space  be- 
tween it  and  the  side  of  the  hole  with  sufficient 
velocity  to  carry  up  the  debris. 

Fig.  96,  again  borrowed  from  Barley,*  shows 
the  derrick  and  general  arrangement  of  the 
plant :  a  is  the  boring  rod  made  of  2^-  inch  (in- 
ternal diameter)  gas-pipe  or  lap-welded  iron  pipe, 
in  lengths  of  25  feet.  The  separate  rods  are 
joined,  as  shown  in  Fig.  97,  by  screwed  spigot 
and  socket  connections  which  are  riveted  on. 

The  short   topmost  piece  of  rod  b  (Fig.  98), 
carries  the  chamber  c,  at  the  base  of  which  the 
head  of  b  can  revolve  freely.     On  the  same  rod  b 
is  keyed  the  spur-wheel  d.     This  is  actuated  by 
the  pinion  e  upon  the  vertical  shaft  f,  which  re- 
ceives its  motion   from   the    horizontal   shaft   h 
(Fig.  96),  through  a  belt  and  the  mitre  wheels  g. 
The  boring  rod  is  driven  at  a  speed  of  80   to 
100  revolutions  per  minute.     It  is  easy  to  under- 
stand from  the  figure  how  the  rope  drums  j  are 
worked  from  the  same  shaft  h  at  slow  or  high 
speed  by  using  one  or  other  of  the  two  clutches 
upon  this  shaft.    Water  is  pumped  into  c  by  a 
hose,  descends  the  rod,  and  passing  through  the  bit  ascends  with 
the  sludge  and  chips  of  rocks. 

As  the  bit  and  rods  descend,  the  carrier  under  the  spur-wheel 
d  follows  them,  and  also  the  pinion  e,  which  is  loose  upon  the 
square  shaft  f. 

Fig.  99  represents  a  favourite  form  of  cutting  tool  or  boring 
bit,  which  begins  by  making  a  small  hole  and  then  speedily 
enlarges  it  to  the  full  diameter. 

As  the  lining  tubes  are  usually  7  inches  in  diameter,  the 
annular  space  between  the  tube  and  the  boring  rod  is  large, 


Op.  tit.  p.  684. 


BORING. 


117 


and  this  is  diminished  by  adding  a  lagging  of  wood  (shown  in 
Fig.  97)  for  the  purpose  of  increasing  the  velocity  of  the  upward 
current  and  so  promoting  the  discharge  of  the  debris. 

The  rapidity  with  which  some  holes  are  bored  by  this  machinery 
is  considerable.     Mr.  Darley  mentions  that  a  hole  had  been  bored 


FIG. 


FIG. 


to  the  depth  of  500  feet,  and  cased  all  the  way  in  n^  days, 
including  the  time  occupied  in  putting  up  the  derrick. 

Another  rotatory  method  for  sinking  wells  or  exploring  in  soft 
or  moderately  hard  ground  consists  in  revolving  the  casing  or 
lining  tube,  which  is  shod  with  hard  steel  teeth,*  whilst  a  stream 
of  water  is  forced  down  through  it ;  the  water  ascends  in  the 
narrow  annular  space  between  the  tube  and  the  sides  of  the  hole. 
The  core  is  gradually  washed  away  by  the  descending  current, 
and  the  inventors  claim  that  any  clay  carried  up  by  the  water 
forms  in  time  a  protecting  shell  to  the  sides  of  the  bore-hole, 
if  composed  of  very  loose  strata.  They  even  send  down  clay, 
chaff,  bran,  or  cement  by  the  tube  for  the  express  purpose  of 
its  making  a  resisting  lining  shell. 

In  the  alluvium  of  the  Mississippi  at  New  Orleans  a  7 -inch 
well  was  bored  in  this  manner  500  feet  deep  in  48  hours. 

For  boring  holes  not  exceeding  40  or  50  feet  ( 1 2  to  1 5  in.)  in  depth, 
which  may  be  required  for  geological  surveys  or  for  investigating 
shallow-lying  deposits,  a  convenient  portable  set  of  tools  has  been 
arranged  by  Messrs.  Van  den  Broeck  and  Kutot.f  It  consists  of 
the  following  parts  :  (i)  a  series  of  rods  4  feet  i  inch  (1*25  m.) 
long,  which  can  be  put  together  by  screw  joints;  (2)  either  a 
chisel  cutter  or  a  twisted  auger,  for  doing  the  actual  boring  ;  and 
(3)  a  handle  which  is  attached  to  the  topmost  rod.  As  accessory 

.*  Encyclopedia  of  Well-Sinking  Appliances.  The  American  Well  Works, 
Aurora,  Illinois,  U.S.A.,  1886,  p.  183. 

t  "  Un  nouvel  appareil,  portatif  de  sondage  pour  reconnaissance  rapide 
du  terrain,"  Bulletin  Soc.  Beige  de  Geologic,  tome  ii.  (Annee  1888),  29  Mai. 


n8 


ORE  AND  STONE-MINING. 


FIG.  ioo. 


parts,  there  are  spanners  for  unscrewing  the  rods,  a  key  for  support- 
ing the  rods  during  this  operation,  and  a  second  handle  which  can 
be  fixed  on  any  part  of  the  line  of  rods  if  more  force  is  required 
for  the  work.  By  a  very  ingenious  clip,  each  joint  can  be  so  fixed 
that  it  cannot  become  unscrewed  during  the  process  of  boring. 
The  diameter  of  the  large  auger  is  if  inch  (45  mm.)  and  the 
cutting  part  has  two  wings  which  are  of  service  in  penetrat- 
ing the  ground.  The  chisel  is  used  for  hard  seams,  such  as 
ironstone,  grit,  and  beds  containing  fossils  or  pebbles ;  like  the 
auger,  it  is  if  inch  across.  The  apparatus  is  very  portable, 
for  no  part  is  more  than  4  feet  i  inch  long  ;  each  rod  weighs  4*4 
Ibs.  (2  kil.),  and  the  total  weight  of  all  the  plant  required  for 
making  a  boring  40  feet  deep  is  only  64  Ibs.  (29  kil.). 

Diamond  Drills. — The  most  important  kind  of  boring  by 
rotation  is  done  with  the  diamond  drill.  The  working  part  of 
the  drill  consists  of  the  so-called  crown,  which 
is  a  short  piece  of  tube  made  of  cast  steel,  at 
one  end  of  which  a  number  of  black  dia- 
monds are  fastened  into  small  cavities.  The 
crown  is  screwed  on  to  wrought-iron  pipes, 
which  constitute  the  boring  rod.  This  is 
made  to  rotate,  and  the  result  is  that  an 
annular  groove  is  cut  at  the  bottom  of  the 
hole,  leaving  a  core  which  often  breaks  off  of 
itself,  is  caught  by  a  little  shoulder,  and 
brought  out  with  the  rod  (Fig.  ioo).*  In 
places  where  it  is  not  necessary  to  make  any 
verification  of  the  rocks  traversed,  the  crown 
may  be  arranged  with  diamonds  in  the  centre 
also,  so  that  the  whole  of  the  bottom  of  the  hole  is  ground  away. 
The  debris  in  either  case  are  washed  away  by  a  stream  of  water, 
which  is  forced  down  the  tube  and  flows  up 
the  sides  of  the  hole. 

In  order  to  prevent  capital  from  being 
locked  up  in  a  stock  of  large  crowns,  Messrs. 
Docwra  sometimes  fix  the  diamonds  in  steel 
plugs,  which  will  fit.  holes  in  any  ring.  The 
diamonds  can  then  easily  be  taken  out  of  one 
crown  and  placed  in  another  without  re- 
setting. 

The  crown  represented  in  Fig.  101  was  the 

largest  employed  at  the  deep  boring  at  Northampton.  It  was 
screwed  to  a  tube  30  feet  long  (Fig.  102),  which  enabled  cores  of 
almost  that  length  to  be  cut  without  withdrawing  the  tool.  The 
object  of  the  open  sediment-tube  above  the  core-tube  was  to  catch 


FIG.  101. 


*  Eunson,  "  On  a  Deep  Boring  at  Northampton,"  Min.  Proc.  Inst.  C.E., 
vol.  Ixxiv.  (1883),  p.  270. 


BORING. 


119 


FIG.  102. 


FIG.  103. 


any  coarse  particles  too  heavy  to  be  carried  up  by  the  water,  as 
well  as  any  fragments  falling  from  the  sides  of  the  hole. 

Though  pieces  of  the  core  often  broke  off  of  themselves  and  came 
up  in  the  tube,  it  was  necessary  to  use  the 
extractor  (Fig.  103) ;  it  consisted  of  a  ring  A, 
which  was  screwed  by  a  few  threads  to  the 
core-tube  in  the  place  of  the  crown.  On 
reaching  the  bottom  of  the  hole  the  screw- 
ing-up  was  continued,  and  the  descent  of  the 
portion  C  gradually  forced  down  six  teeth, 
such  as  B,  into  the  position  shown  by  B', 
gripping  the  core  tightly.  If  not  broken  off 
completely  by  this  action,  it  gave  way  when 
the  tube  was  pulled,  and  came  up  inside  it. 

The  "  Dauntless"  (Fig.  104)  is  one  of  the 
diamond  drills  made  by  the  Bullock  Manu- 
facturing Company,  of  Chicago,  for  boring 
prospecting  holes,  and  is  capable  of  drilling  a 
2 -inch  hole  to  a  depth  of  more  than  2000 
feet,  and  furnishing  cores  of  iTVjh  inch  in 
diameter.  Cores  show- 
ing visible  gold  have 
lately  been  brought  up 
from  a  hole  2500  feet 
deep,  bored  by  one  of 
these  drills  near  Johan- 
nesburg. 

The  machine  is  con- 
structed as  follows :  A 
is  one  of  a  pair  of  cylin- 
ders, driven  by  steam 
or  compressed  air,  which 
work  the  bevel  wheel 
B  by  gearing.  The  feed-screw  CC  can  slide  readily  up  and 
down  through  B ;  but  as  B  carries  a  feather  lying  in  a  slot  in  C, 
the  latter  is  driven  round  when  the  former  rotates.  D  is  the 
crown  set  with  diamonds,  screwed  on  to  the  first  piece  of  boring 
tube  C",  attached  to  C  by  the  chuck  C'.  The  hose,  E,  coming 
from  a  special  pump,  brings  in  a  continuous  supply  of  water 
which  passes  down  C  and  comes  out  through  D.  F',  F",  F'", 
and  G',  G",  G"',  constitute  the  differential  feed-gear  for  causing 
the  feed-screw  C,  and  consequently  the  bit  D,  to  descend  as  the 
hole  is  deepened. 

F7,  F",  and  F"7  are  connected  with  B  so  that  they  revolve  when 
it  does ;  G',  G",  and  G"'  are  loose  upon  the  counter-shaft,  but  any 
one  of  them  can  be  made  fast  to  it  by  operating  the  clutch  H. 
K  is  a  toothed  wheel  attached  solidly  to  the  bottom  of  a  feed-nut 
through  which  C  passes  ;  when  K  rotates  it  causes  C  to  ascend  or 


—  15 


120 


ORE  AND  STONE-MINING. 


descend.     L  is  a  wheel  equal  in  size  to  K,  which  it  drives  when 
its  shaft  is  rotated  by  G',  G",  or  G'". 

If  F'  and  G'  had  the  same  number  of  teeth  each,  one  revolution 

FIG.  104. 


of  B  would  make  one  revolution  of  G',  one  revolution  of  L,  and 
one  revolution  of  K ;  consequently  the  feed-nut  attached  to  K 
would  be  revolving  at  the  same  rate  as  C,  and  C  would  not  descend. 
In  reality  G',  G",  and  G'"  have  a  slightly  smaller  number  of  teeth 
than  E',  F",  and  F'";  therefore  one  revolution  of  F'  causes  slightly 


BORING.  121 

more  than  one  revolution  of  G',  K  moves  rather  faster  than  C,  and 
0  descends  slowly.  As  arranged  in  this  particular  case,  the  gear 
F7  G7  causes  C  to  descend  i  inch  for  every  300  revolutions, 
the  gear  F"  G'7  gives  a  feed  of  i  inch  for  every  450  revolutions, 
and  F'"  G'"  a  similar  feed  for  750  revolutions.  The  driller  is 
thus  enabled  to  regulate  his  feed  to  the  hardness  of  the  rock 
bored.  In  practice  these  three  speeds  of  advance  have  been  found 
sufficient. 

M  is  a  drum  which  is  used  for  hoisting  the  rod  out  of  the  hole ; 
N  is  the  hinge  upon  which  the  whole  of  the  boring  head  can  be 
turned,  so  as  to  leave  the  mouth  of  the  hole  perfectly  free  while 
raising  or  lowering  rods.  O  is  the  thrust  register,  upon  which  is 
indicated  by  a  dial  the  resistance  exerted  by  the  rock  against  the 
bit.  This  is  an  addition  of  great  importance,  for  by  watching  the 
indicator  the  driller  can  detect  changes  in  the  hardness  of  the 
strata  passed  through,  and  can  measure  the  exact  thickness  of  the 
hard  and  soft  beds  before  he  has  seen  either  the  cuttings  or  the  cores. 
The  thrust  register  prevents  the  possibility  of  drilling  through  a 
bed  of  coal  or  other  mineral  without  its  being  noticed,  as  has 
happened  when  the  seam  was  so  soft  that  it  failed  to  furnish  a 
core,  The  rod  is  lengthened  as  the  drilling  proceeds  by  screwing 
on  piece  after  piece  between  C'  and  the  topmost  rod  projecting 
above  the  hole. 

Mr.  Bullock  has  recently  brought  out  a  contrivance  by  which 
the  core  can  be  drawn  up  through  the  hollow  boring  rods  without 
removing  them  from  the  hole.  The  immense  saying  of  time 
•effected  in  this  manner  is  of  supreme  importance  when  boring  at 
great  depths. 

The  large  rock  drill  used  by  the  American  Diamond  Rock 
Boring  Company,*  for  putting  down  holes  to  a  depth  of  2000 
feet,  consists  of  a  20  horse-power  boiler  with  two  oscillating 
6-inch  cylinders  and  the  necessary  gearing  for  working  the  drill, 
.all  mounted  on  a  carriage,  so  that  the  whole  machine  is  readily 
moved  from  place  to  place.  The  feed  is  effected  hv  Bearing,  or 
VL^by  hydraulic  pressure,  a  2  f -inch  crown  is  employed,  leaving  a 
.2 -inch  core.  Each  separate  drill  rod  is  10  feet  long.  The  total 
weight  of  the  machine  is  about  four  tons. 

The  newt  Victorian  Giant  Drill,  said  to  be  the  largest  and  most 
powerful  drill  in  Australia,  contains  some  improvements  suggested 
by  experience.  The  cylinders  are  7^  inches  in  diameter,  and  are 
made  stationary,  because  the  heavy  vibrations  of  oscillating 
cylinders  are  imparted  to  the  boring  rods  and  diamond  bit,  and 
do  harm  to  the  machinery.  The  winding  drum  has  a  friction 
pulley  and  a  brake,  which  enable  the  rods  to  be  lowered  without 
working  the  engine,  and  so  prevent  unnecessary  wear  and  tear. 

*  Eng.  Min.  Jour.,  vol.  xlviii.  (1889),  p.  569. 

t  Victoria,  Annual  Report  of  the  Secretary  for  Mines  for  the  Year  1889. 
Melbourne,  1890,  p.  35. 


122  ORE  AND  STONE-MINING. 

Various  parts  are  strengthened,  and  there  is  an  arrangement  for 
working  the  steam  expansively. 

This  method  of  boring  is  expensive.  During  the  year  1889, 
the  cost  of  prospecting  for  gold  by  diamond  drills  in  Victoria*  was 
i os.  3jjjd.  per  foot  bored,  exclusive  of  the  wear  and  tear  of 
diamonds,  taking  the  average  of  a  total  18,454  feet  bored.  The 
cost  for  the  wear  and  tear  of  diamonds  for  30,294  feet  bored  in 
search  of  coal  and  gold  is  put  down  at  ^6000,  or  nearly  43.  per 
foot.  In  the  borings  executed  by  the  Government  of  New  South 
Wales,f  the  cost  for  diamonds  is  very  much  less,  varying  as  a  rule 
from  is.  to  2S.  per  foot.  This  may  probably  be  accounted  for  by 
the  fact  that  most  of  the  New  South  Wales  bore-holes  were  made 
in  the  comparatively  soft  Carboniferous  strata,  whilst  some  of 
the  bore-holes  for  deep  leads  in  Victoria  had  to  traverse  hard 
basalt. 

The  cost  at  Broken  Hill,  where  a  boring  3  inches  in  diameter 
was  carried  from  1122  feet  to  a  depth  of  1880  feet  in  1889,  was 
£i  95.  iojd.,  or,  roughly  speaking,  303.  per  foot,  exclusive  of 
office  salaries,  store  wages,  rent,  and  the  Superintendent  of 
Drills'  travelling  expenses.  The  rocks  traversed  were  gneiss, 
mica  schist  and  quartzite,  sometimes  garnetiferous.  The  average 
rate  of  boring  was  only  571  inches  per  hour,  whilst  in  the  sandstone 
and  shale  of  the  Carboniferous  strata  there  was  a  progress  of  9 
to  31  inches  per  hour,  at  a  cost  (exclusive  of  the  items  mentioned 
above)  of  6s.  2d.  to  i8s.  4d.  per  foot.  The  average  working  cost 
of  7854  feet  bored  by  the  Department  of  Mines,  New  South 
Wales,  in  1889,  including  all  expenses,  was  143.  3^-d.  per  foot. 
Of  the  total  7854  feet,  no  less  than  7096  were  in  strata  of  Car- 
boniferous age,  and  only  758  in  metamorphic  schists;  the  holes 
were  from  2\  inches  to  4  inches  in  diameter. 

With  reference  to  the  rate  of  boring,  it  must  be  remembered 
that  the  figures  given  refer  to  the  speed  obtained  while  the 
machine  was  at  work,  but  the  average  amount  of  deepening  of 
the  hole  at  Broken  Hill  during  the  year  was  little  over  2  feet  per 
day.  Omitting  Sundays,  there  were  313  working  days.  Only 
199,  or  less  than  two-thirds,  were  employed  in  boring;  of  the 
remainder,  86  were  occupied  in  repairing,  15  in  reaming,  4  by 
delays,  9  by  holidays ;  the  working  day  was  eight  hours. 

The  amount  of  core  obtained  at  Broken  Hill  compared  with 
the  total  depth  bored  was  as  much  as  97 -J  per  cent.,  and  the  average 
for  the  total  7854  feet  referred  to  above  was  89-33  per  cent.,  a 
very  excellent  result. 

Small  diamond  drills,  which  will  bore  in  any  direction,  and 
which  are  driven  by  hand,  compressed  air,  or  electricity,  are 
largely  used  underground  for  prospecting.  The  hand  drill  of  a 

*  Op.cit.,p.  63. 

t  Annual  Report  for  the  Department  of  Mines,  New  /South  Wales,  for  the 
Tear  1889.  Sydney,  1890,  p.  139. 


BORING. 


123 


Swedish  boring  company*  gives  cores  J  inch  in  diameter.  Ex- 
ploration by  these  little  machines  is  very  decidedly  cheaper  than 
by  driving  or  sinking  by  hand  in  hard  rocks,  and  fully  ten  times  as 
quick.  On  the  other  hand,  the  ground  is  not  opened  out  as  it  would 
be  by  a  shaft  or  drift,  and  the  sample  furnished  is  but  small. 

Several  good  veins  have  been  discovered  by  the  aid  of  the  little 
hand-machine  in  Scandinavia — for  instance,  a  copper  lode  1 5  feet 
(4*5  m.)  wide  at  Roraas,  and  iron  lodes  from  32  to  65  feet 
(10  m.  to  20  m.)  wide  at  Dannemora  and  Persberg. 

The  hand-power  drill  of  the  Bullock  Manufacturing  Company, 
Chicago,  is  a  somewhat  similar  little  machine,  and  it  is  said  to  be 


FIG.  105. 


FIG.  1 06. 


capable  of  boring  a  hole  of  if  inch  diameter,  with  a  i  js¥  inch 
core,  to  a  depth  of  400  feet. 

Machines  driven  by  compressed  air  are  often  employed  at 
ore  mines  in  the  United  States  for  exploratory  purposes. 
Fig.  105  shows  the  Little  Champion  prospecting  drill.  Two 
inclined  cylinders  drive  a  horizontal  crank-shaft,  which  works 
bevel  gear,  causing  the  drill  to  revolve.  At  the  same  time  a 
counter-shaft  is  likewise  set  in  motion,  and  this  effects  the 
advance  of  the  drill  by  driving  the  feed-screw,  in  the  manner 
already  explained  in  the  description  of  the  "  Dauntless  "  machine 

*  Nordenstrom,  "  Die  Diamantbohrmaschine  mit  Handbetrieb,"  B.  u.  h. 
Z.  1889,  pp.  389  and  449  ;  and  Petiton,  Bull.  Soc.  2nd.  Min.,  36  Serie,  vol. 


lii.  (1559),  P-  1395- 

t  Eng.  Min.  Jour.,  vol.  xxxiii.  (1882),  p.  119. 


124  ORE  AND  STONE-MINIHG. 

(p.  120).  The  feed-screw  and  its  connections  are  carried  by  a 
swivel-head,  and  this  can  be  turned  so  as  to  drill  holes  at  an 
angle.  The  drum  shown  above  the  cylinders  is  used  for  hoisting 
out  the  drill-rods  by  a  rope.  The  rods  are  lap-welded  iron  tubes 
1 1  inch  in  diameter,  fitted  with  a  bayonet  joint. 

Another  light  portable  prospecting  drill  for  underground  work 
is  represented  in  Fig.  106.*  It  is  intended  for  drilling  holes 
ij  inch  in  diameter  to  a  depth  of  150  feet.  The  cores  which  it 
yields  are  J  inch  in  diameter.  It  has  double  oscillating  cylinders 
3^  inches  in  diameter,  with  3 \  inches  stroke,  which  are  run  up  to 
a  speed  of  800  revolutions  a  minute.  The  drill  can  be  set  to 
bore  in  any  direction  by  turning  the  swivel-head  on  which  it  is 
carried. 

The  Sullivan  prospecting  drill  is  a  diamond  borer  driven  by  an 
electric  motor  on  the  same  frame  as  the  drill.  The  motor  also 
works  the  force-pump.  The  feed  is  not  by  toothed  wheels  as 
shown  in  the  figures,  but  by  friction  gearing.  It  will  bore  at  any 
angle  to  a  depth  of  300  feet. 

Georgi's  t  electric  diamond  drill,  primarily  intended  for  boring 
holes  for  blasting,  can  also  be  employed  for  prospecting  under- 
ground. 

Substitutes  for  Diamonds. — Olaf  TerpJ  uses  emery  instead 
of  diamonds.  In  some  cases  he  puts  in  the  fragments  of  emery 
loose  at  the  bottom  of  the  hole  and  allows  them  to  wedge  them- 
selves into  grooves  in  the  boring  crown,  which  is  made  of  soft 
metal.  Another  plan  is  to  make  the  boring  crown  entirely  of 
emery.  The  speed  of  rotation  is  three  or  four  times  as  great  as 
with  diamonds,  and  holes  can  be  bored  from  f  inch  (20  mm.) 
to  3  feet  4  inches  (i  m.)  in  diameter.  Healey  bores  with  small 
chilled  cast-iron  shot,  which  are  dropped  into  the  hole  while  a 
wrought-iron  tube  is  revolving  in  it.  The  debris  are  carried  up 
by  water,  and  the  cores  are  extracted  in  the  ordinary  way. 


II.  BORING  BY  PERCUSSION  WITH  RODS. 

Iron  Rods. — The  rods  are  either  of  iron  or  wood.  In  France 
preference  is  given  to  iron,  and  the  following  details  relate  to 
modes  of  construction  now  employed  by  M.  Paulin  Arrault,§  the 
well-known  boring  engineer  of  Paris. 

The  actual  boring  apparatus  consists  of  the  cutting  tool,  the 
rods,  and  the  driving  machine ;  but  in  addition  it  is  necessary  to 

*  Eng.  Mln.  Jour.,  vol.  xxxiii.  (1882),  p.  273. 

t  Jahrb.f.  d.  Berg-  und  Hiittenwesen  im  K.  SacJisen,  1890,  p.  95. 

I  Olaf  Terp's  "  Bohrmaschine  mit  Schmirgelbohrkrone,"  B.  u.  h.  Z.,  1890, 
P-  4i5- 

§  The  figures  are  copied  by  permission  from  M.  Arrault's  work,  Outils 
et  proctdts  de  Bondage.  Paris,  1890. 


BORING.  125 

have  clearing  tools,  and  appliances  for  remedying  accidents,  lining 
the  bore-holes,  and  obtaining  samples  of  the  rocks  traversed. 

Cutting  Tools. — The  actual  cutting  tool  is  usually  a  chisel  (Fig. 
107)  of  some  kind ;  for  soft  rocks  the  edge  is  straight ;  for  hard 
rocks  there  are  wings  to  guide  the  tool  and  keep 
the   hole   vertical,   or  even    special  guides   above       FIG.  107. 
it.     For  diameters  not  exceeding  40  inches  (i  m.), 
there  is  usually  only  one  chisel;  but   the  actual 
cutting  blade  is  sometimes  made  in  a  separate  piece 
fastened  by  gibs  and  cotters  to  the  tool  carrier  (Fig. 
1 1 8).     In  boring  larger  holes  the  chisel  is  made  of 
two,  three,  or  four  separate  blades. 

Boring  Rods. — The  boring  rods  are  made  of  iron 
of  square  section.     The  usual  mode  of  connection 
is  by  a  screw- joint  such  as  is  shown  in  Fig.  108, 
care  being  taken  to  have  all    the   bars  alike,   so 
that  any  two  bars  can  be  screwed  together.     M.  Arrault  prefers 
to  have  a  connecting  socket  (Fig.  109).     The  ordinary  rods  have 
a  thread  at  each  end,  to  one  of  which  is  screwed  a  socket  or  sleeve 
which  is  fixed  by  a  pin.     This  socket  then  receives  the  end  of 
another  rod,  which  is  screwed  up  until  both  ends  meet.     When 
the  thread  of  a  socket  becomes  worn,  it  is  taken 
off  and  put  on  to  the  other  end  of  the  rod  ;  in  a    FIGS.  108  &  109. 
similar  manner,  if  the  thread  of  a  rod  is  worn, 
the  socket  may  be  screwed  on  to  it  and  the  un- 
worn end  used  in  the  process  of  jointing  and 
unjointing.     The  rods  are  generally  screwed  up 
to  the  right  and  are  turned  in  that  direction  ; 
but  in  special  cases  it  may  be  necessary  to  have 
the  sockets  fixed   by   two  pins,  or  to  have  a 
special  joint  or  a  left-handed  thread. 

The  height  of  the  tower,  derrick,  or  shears 
erected  above  the   bore-hole  should   be    some 
multiple  of  the  length  of  the  rods,  so  as  to  be  able  to  detach  or 
attach  two  or  three  lengths  at  a  time,  instead  of  having  to  make 
and  unmake  every  joint. 

FIG.  no.  FIG.  in.  FIG.  112. 


Arrault's  rods  vary  in  length  from  i  foot  8  inches  (0*50  m.)  to 
20  feet  (6  m.),  being  usually  an  exact  number  of  metres,  and  in 
size  from  J  inch  (22  mm.)  to  3!  inches  (90  mm.)  on  the  side. 


126 


ORE  AND  STONE-MINING. 


They  have  two  shoulders  at  each  extremity,  so  that  the  upper  one 
can  be  used  with  the  lifting  hook,  Fig.  no,  when  the  lower  is 
resting  upon  the  key,  Fig.  in. 

A  cap  such  as  Fig.  112,  maybe  screwed  on  and  used  instead  of 
the  lifting  hook  for  raising  the  rods  by  the  rope. 

Working  the  Rod. — The  up-and-down  movement  of  the  rods  may 
be  obtained  in  various  ways.  For  depths  not  exceeding  60  to  80 

FIG.  113. 


feet,  nothing  can  be  simpler  than  the  device  shown  in  Fig.  113. 
The  man  at  the  windlass  raises  the  rods  by  turning  the  handle,  and 
the  master  borer  detaches  them  and  causes  them  to  fall  by  simply 
pressing  down  the  end  of  the  hook,  which  he  holds  in  his  right 
hand.  The  chain  is  lowered,  the  hook  put  in,  the  rods  are  raised 
by  the  winch,  and  then  again  allowed  to  fall,  the  master  borer 
taking  care  to  turn  them  a  little  each  time. 


BORING. 


127 


Fig.  114  shows  the  principal  tools  supplied  by  Arrault  f or  a 
small  boring. 

For  greater  depths  a  lever  has  to  be  employed,  the  rods  being 
suspended  at  one  end,  while  the  other  can  be  pressed  down  by 
men  using  their  hands  or  feet.  The  spring  pole  is  another 
arrangement ;  the  pole  is  pulled  down  to  make  the  stroke,  and 
its  elasticity  lifts  the  rod  again.  The  length  of  the  stroke  can  be 

FIG.  114. 


B 


i,  guide  tube;  2,  bit  or  chisel  with  wings;  3,  straight  bit  or 
chisel :  4,  ordinary  open  scoop  or  wimble ;  5,  scoop  or  wimble 
with  auger ;  6,  closed  scoop  ;  7,  sludger  with  ball  valve  ;  8,  bell- 
screw  or  screw  grab  ;  9,  auger  ;  10,  combination  bit  and  sludger 
with  ball  valve;  n,  combination  auger  and  sludger  with  ball 
valve;  12,  boring  rod;  13,  matching  piece;  14,  wrench  for  un- 
screwing rods  ;  15,  matching  or  lengthening  piece  ;  16,  clamp ; 
17,  clamp  with  eye  ;  18,  wrench  ;  19,  retaining  or  supporting  key  ; 
20,  cap ;  21,  tiller  ;  22,  double  wrench  ;  23,  scraper;  24,  picker. 

rendered  uniform  during  the  boring  by  means  of  a  screw  in  a 
swivel-head  at  the  top  of  the  rod. 

With  deep  holes,  and  especially  those  of  large  diameter,  steam 
machinery  has  to  be  employed  for  working  the  rod.  Arrault 
frequently  uses  a  winch  driven  by  steam.  The  chain  to  which 
the  rods  are  attached  passes  over  a  pulley  hung  from  a  derrick 
and  is  coiled  on  a  drum,  which  is  loose  upon  the  main  axle  of  the 
winch ;  it  can  be  thrown  in  and  out  of  gear  by  a  clutch  moved  by 
a  lever.  It  is  easy  therefore  to  raise  the  rods  by  working  the 
winch,  and  then  let  them  drop  by  simply  releasing  the  clutch. 


128  ORE  AND  STONE-MINING. 

Occasionally  a  direct-acting  engine  is  placed  immediately 
above  the  bore-hole,  but  a  commoner  arrangement  is  to  employ  a 
single-acting  cylinder  with  its  piston  acting  at  one  end  of  a 
beam,  while  the  rods  are  attached  to  the  other  end.  A  favourite 
plan  also  is  to  actuate  the  beam  by  a  connecting  rod  worked  by  a 
crank. 

Process  of  Boring. — The  actual  machinery  has  now  been 
described,  and  the  mere  boring  appears  to  be  a  very  simple 
matter,  consisting  only  in  lifting  the  rod  a  little  and  allowing  it 
to  drop,  after  turning  it  slightly  before  each  stroke.  Never- 
theless the  process  of  putting  down  a  bore-hole  is  far  more  com- 
plicated than  it  might  seem,  for  there  are  numerous  operations 
which  take  up  much  time.  In  the  first  place  the  debris  must  be 
removed  by  a  clearing  tool,  and  before  this  can  be  lowered  the 
cutting  tool  must  be  taken  off.  The  swivel-head  is  disconnected, 
and  a  cap  screwed  on  ;  a  length  of  rod  is  now  drawn  up  by  a  hand 
or  a  steam  windlass,  the  retaining  key  is  put  under  a  shoulder, 
and  the  joint  unscrewed  by  another  key.  It  is  well  to  have  as 
many  c/ips  as  there  are  lengths  to  be  drawn  up,  and  then  each 
length  can  be  suspended  in  the  boring  house  or  derrick. 

As   soon    as  the   hole   is  free    the   clearing   tool  is   lowered, 
either  by  the  rods  in  precisely  the  same  way  as  the  boring  chisel, 
or  by  means  of  a  rope  and  windlass.     The  clearing  tool 
FIG.  115.    is  usually  a  hollow  cylinder  with  an  ordinary  clack  or 
a  ball  valve  (shell  pump  or  sludger)  (Fig.  115).     It  is 
worked  up  and  down  a  little  till  it  is  filled,  and  it  is 
then  drawn  up  to  the  surface  and  emptied.     The  opera- 
tion is  repeated  if  necessary,  and  the  boring  is  resumed 
with  the  rod.     Sometimes  a  cutting  blade  is  added  to 
the  sludger  so  that  it  bores  a  little  and  picks  up  the 
debris  at  the  same   time.     In  certain  rocks  such  as 
marls,  it  is  convenient  to  have  a  shell-pump  with  a 
lip.     It  is  fixed  to  the  rods,  and  when  it  is  turned  a 
little  as  well  as  moved  up  and  down,  it  soon  fills  itself. 

Oeynhauseris  Joint  and  free-falling  tools. — When  a  hole  of  large 
diameter  is  being  bored,  the  weight  of  the  rods  is  so  great 
that  much  vibration  ensues  when  they  are  suddenly  arrested 
by  the  chisel  striking  against  the  bottom.  Yarious  devices  have 
been  contrived  for  overcoming  this  difficulty,  among  which  may 
be  mentioned  Oeynhausen's  sliding  joint  and  three  methods  of 
making  the  tool  fall  independently  of  the  rod.  Oeynhausen's 
contrivance  (Figs.  116  and  117)  consists  of  an  upper  piece  a  pro- 
vided with  a  slot  in  which  the  lower  piece  b  can  slide  ;  b  is  pre- 
vented from  dropping  out  by  a  crosshead  and  carries  the  boring 
chisel,  whilst  a  is  attached  to  the  line  of  rods. 

When  a  down-stroke  is  made  and  the  chisel  strikes  the 
bottom,  the  piece  a  slides  over  b  and  is  therefore  but  little 
affected  by  any  jar  produced  by  the  blow  of  the  tool.  The  length 


BORING. 


129 


FIGS.  116,  117  &  118. 


ft. 


C 


of  the  stroke  is  arranged  so  that  the  top  of  the  slot  will  not 
descend  far  enough  to  touch  the  crosshead  ;  a  is  then  raised  once 
more  and  again  catches  the  crosshead. 
One  of  the  simplest  arrangements 
for  making  the  tool  fall  independently 
is  the  sliding  joint  shown  in  Fig.  118. 
The  piece  supporting  the  boring  tool  has 
two  wings  (-Fig.  119)  which  rest  upon 
shoulders,  at  the  top  of  a  long  slot  in 
a  cylinder  attached  to  the  lowest  rod  ; 
by  giving  the  rods  a  sharp  turn  to 
the  left,  the  wings  lose  their  support 
and  the  tool  drops. 

The   actual    process   of    boring    is 
carried  on  in  the  following  manner  : — 
The  line  of  rods  suspended  to  a  chain 
is  raised  by  a  steam  winch. 
FIG.  119.  Steam  is  then  shut  off,  and 
the  master  borer  by  a  sudden 
twist  of  the  tiller  causes  the 
bayonet  joint  to    act ;    the 
tool  drops  and  makes  its  cut. 
The  rods  are  then  lowered, 
and    the    slot   comes    down 
over  the   wings   which   are 
pressed  by  the  inclined  sur- 
faces at  the  end  on  to  the 
shoulders;     the     steam     is 
turned  on  again,  and  the  operations  of 
winding  up,  stopping,  twisting,  letting 
the  tool  fall  and  lowering  are  repeated. 
The  contrivance  acts  so  easily  that  it  is 
sometimes  used  even  for  comparatively 
v~v      shallow  bore-holes. 

LJ  The  free  fall  is  obtained  by  Arrault  in 

a  different  manner  when  the  boring  is 
done  by  a  beam  (Fig.  120).     The  tool  is  suspended 
from  the  catch  h  (Fig.  121).     The  part  a  b  has  a 
pin  it  which  lies  in  an  oval  hole.     While  the  rods 
are  being   lifted  the    beam   strikes   a   bumping- 
piece,   and  their   upward  movement   is  suddenly 
checked  ;  inertia  carries  the  catch  a  b  up  a  little, 
the  end  a  strikes  an   inclined  surface  and  causes  the  end  b  to 
move  outwards  and  detach  the  tool.     When  the  rods  are  lowered 
the  part  h  hooks  itself  on  without  difficulty,  and  the  chisel  is 
raised  and  dropped. 

This  tool  requires  the  boring  rod  to  be  guided,  for  otherwise  the 
hole  might  not  be  bored  straight. 


130 


ORE  AND  STONE-MINING. 


Fig.  122  explains  a  well-known  free-falling  tool  invented  many 
years  ago  by  Kind.*     The  head  of  the  actual  boring  rod  is  held 


FIG.  121. 


FIG.  122. 


FIG.  120. 


by  a  click  or  grapple.  When  the  main  rod  descends,  the  resist- 
ance of  the  water  in  the  hole  checks  the  sliding  disk  D ;  the  jaws 
J  J  are  opened  by  the  little  rod  which  connects  them  to  D,  and 
the  boring  part  falls  and  strikes  the  bottom  without  any  injurious 
vibrations  being  communicated  to  the  main  rod.  When  the  disc 
descends  further,  the  head  is  caught  again  by  the  click. 

Accidents. — Tools  for  putting  things  right  in  case  of  accident 
are  numerous,  and  many  of  the  contrivances  which  have  been 
invented  by  engineers  are  extremely  ingenious. 

Among  the  accidents  is  a  breakage  of  the  rod.  If  the  rods  are 
not  caught  in  any  way,  a  claw  called  the  crow's-foot  (Fig.  123)  is 
lowered  and  turned  round  till  it  catches  a  rod  below  one  of  the 
shoulders  ;  it  is  then  drawn  up.  Sometimes  it  is  found  that  a  hole 
has  suddenly  deviated  from  the  vertical,  owing  to  a  difference  in 
hardness  in  the  rock,  which  causes  the  chisel  to  work  more  easily 
on  one  side  than  the  other.  One  method  of  remedying  this  evil 
is  to  fill  the  bad  part  with  cement,  and  rebore  it  very  carefully. 

Broken  ropes  can  be  caught  hold  of  by  tools  resembling  a  cork- 
screw. The  tool  shown  in  Fig.  124  serves  to  cut  a  thread  upon 
the  end  of  a  broken  rod.  The  position  of  the  broken  end  is  first 

*  J.  Gallon,  Lectures  on  Mining,  vol.  i.,  Atlas,  Plate  IX.,  Fig.  52. 


BORING. 


ascertained  by  taking  an  impression  upon  tallow  or  wax,  and  the 
cone  is  then  lowered  on  to  it ;  by  turning  it  round  a  thread 
is  cut  on  the  broken  end,  which  can  now  be  raised  with  the  rods 
and  tools  attached  to  it. 

If  the  cutting  chisel  is  broken,  some  kind  of  grasping  nippers 
must  be  used,  and  there  are  contrivances  for  making  them  act 
when  they  have  reached  the  bottom  of  the  hole. 

Linings. — Where  the  strata  are  soft  and  would  fall  in,  or  where 
it  is  necessary  to  shut  off  the  inflow  of  certain  water-bearing 
beds  in  order  to  confine  the  well  to  one  particular  source  of 


FIGS.  i?3  &  124. 


FIG.  125. 


FIG.  126. 


supply,  the  hole  has  to  be  lined  with  a  tube.  Tubes  are  made  of 
iron,  copper,  or  wood.  This  last  material  is  seldom  employed 
nowadays,  because  it  occupies  so  much  space,  and  because  it  is  not 
easy  to  make  good  wooden  tubes. 

Fig.  125  is  a  tube  of  riveted  sheet  iron  with  sockets  fixed  on, 
which  enable  the  joints  to  be  made  by  screwing.  Fig.  126  is  a 
tube  with  a  screwed  joint  perfectly  smooth  outside  and  inside. 
Copper  tubes  are  advisable  when  the  water,  such  as  that  coming 
from  pyritiferous  beds,  would  attack  iron  and  in  time  eat  it  away; 
but  this  difficulty  is  also  overcome  by  putting  earthenware  pipes 
inside,  and  filling  up  the  interspace  with  cement. 

Cores. — Though  the  fragments  brought  up  in  the  sand-pump 
will  indicate  the  nature  of  the  rocks  which  are  being  traversed,  it 
is  often  desirable  to  obtain  a  core  of  the  actual  stratum  itself, 
which  will  show  the  direction  and  amount  of  the  dip  of  the 
rocks,  and  possibly  contain  fossils  and  so  afford  valuable  knowledge 
concerning  their  precise  age.  A  core  is  cut  out  either  by  rota- 
tion or  percussion.  In  the  former  case  the  tool  consists  of  a 
sheet-iron  cylinder  (Figs.  127  and  128)  armed  at  the  bottom  with 


I32 


ORE  AND  STONE-MINING. 


steel  sawing  teeth ;  in  the  latter  the  cylinder  is  surrounded  by 
four  cutting  chisels,  which  chip  out  a  ring  and  leave  a  solid 
cylinder  standing. 

The  core  now  has  to  be  detached,  and  for  this  purpose  various 
contrivances  may  be  adopted.  One  of  Arrault's  tools  is  shown  in 
Fig.  129.  It  is  a  hollow  cylinder  a  attached  to  the  fork  b  c,  with  a 
longitudinal  slot  containing  a  sliding  bar  d,  armed  with  a  toothed 
wedge  e,  which  is  prevented  from  dropping  out  by  the  shoulder./. 
The  bar  d  is  further  kept  in  position  by  the  spring  g  h,  fixed  at 


FIGS.  127  &  128. 


FIG.  129. 


l— 


Section  at  A  B. 


the  top  of  the  tube,  which  presses  it  against  the  two  outer  plates 
ij  and  the  ring  k  ;  I  is  a  little  slot  in  the  spring,  and  m  a  small 
stud  upon  the  bar  d.  When  this  tool  is  lowered  over  the  core 
and  the  wedge  e  touches  the  bottom  of  the  annular  groove  around 
it,  the  tube  slides  down  and  forces  the  wedge  inwards ;  the 
weight  of  the  rods  causes  sufficient  pressure  to  drive  the  teeth  of 
the  wedge  into  the  core  and  break  it  off.  In  the  meantime  the 
slot  I  has  passed  over  the  stud  m ;  the  wedge  is  thus  prevented 
from  slipping  down,  and  the  core  is  held  till  it  is  drawn  up  to  the 
surface. 

In  order  that  the  direction  of  the  dip  may  be  ascertained  from 
the  core,  it  is  necessary  to  know  exactly  how  it  stood  when  it  was 


BORING. 


133 


in  situ.  In  Victoria*  the  rods  and  the  core-breaker  are  put 
together  at  the  surface,  and  all  the  joints  are  marked  in  a  straight 
line  with  a  chisel.  The  rods  are  then  taken  apart,  and  are  care- 
fully screwed  together  in  precisely  the  same  manner  when  thejT 
are  lowered  into  the  bore-hole.  If  the  position  of  the  marks  at 
the  surface  is  noted  while  the  core  is  being  detached,  the  direction 
of  the  dip  can  at  once  be  determined.  To  prevent  the  possibility 
of  error  from  a  movement  of  the  core  after  it  has  been  detached, 
it  is  marked  while  at  the  bottom  of  the  hole  with  a  vertical 
scratch  or  groove.  This  is  made  by  a  sharp  steel  point  on  the 
gripper  as  it  slides  down  over  the  core. 

A  method  lately  invented  by  Arrault  consists  in  lowering  a 
compass,  enclosed  in  a  case  made  of  phosphor  bronze,  on  to  the 


FIG.  130. 


FIG.  I30A. 


top  of  the  core  (Figs.  130  and  I30A).  The  case  has  an  india- 
rubber  base,  with  two  grooves  filled  with  felt  impregnated  with 
a  thick  ink.  The  compass  case  also  contains  clockwork,  arranged 
like  an  alarum,  which  can  be  made  to  liberate  a  catch  and  so 
clamp  the  compass.  The  compass  is  lowered  by  a  rope,  and  suffi- 
cient time  is  given  to  enable  it  to  assume  its  proper  position  before 


*  ^Reports  and  Statistics  of  the  Mining  Department,  Victoria,  for  ilie  Quarter 
ended  March  j/,  1891,  p.  28,  with  Plate. 


ORE  AND  STONE-MINING. 


t 


it  is  fixed  by  the  clockwork.  It  is  drawn  up,  the 
core  is  then  extracted,  and  by  means  of  the  ink  marks 
the  compass  can  be  put  upon  the  core  in  precisely  the 
same  position  as  it  originally  occupied  in  the  hole. 

Instead  of  using  ink  marks,  some  plastic  material* 
such  as  clay  may  be  lowered  on  to  the  top  of  the  core 
and  allowed  to  remain  long  enough  to  take  an  impres- 
sion. A  clockwork  arrangement  in  a  watertight  box 
above  the  plastic  lump  sets  a  magnet  fast  after  the 
lapse  of  a  given  time  as  before,  and  when  the  core  is 
brought  up  it  is  placed  so  as  to  fit  the  impressions, 
the  orientation  of  which  is  known  by  the  magnet.t 

Wooden  Rods. — In  some  districts  wooden  rods  are 
found  more  suitable  than  iron  ones.  They  have  been 
used  in  Canada,  and  they  are  preferred  in  Galicia. 
Fig.  131  represents  the  manner  in  which  the  rods  are 
made  for  boring  oil  wells  in  that  country.  The  rods 
employed  in  Galicia  are  of  ash,  32  feet  10  inches  (10  m.) 
long,  and  2  inches  in  diameter ;  at  each  end  a  forked 
iron  coupling  is  riveted  on,  terminating  by  a  conical 
male  or  female  screw,  and  in  the  middle  are  two 
strapping  plates  of  iron  to  give  more  strength  and 
stiffness.  To  the  end  of  the  lowest  rod  is  attached  an 
Oeynhausen  sliding  joint  which  carries  a  sinker  bar 
with  the  cutting  chisel  attached  to  it.  The  sinker 
bar  is  from  20  to  30  feet  (6  to  9  m.)  long,  and  weighs 
from  12  to  15  cwt.  (600  to  750  kil.). 

The  top  of  the  line  of  rods  is  fastened  to  a  chain 
(Fig.  132)  ;  this  makes  three  turns  round  one  end  of 
the  boring  beam,  capped  for  this  purpose  by  a  casting 
with  a  spiral  groove,  and  is  then  wound  on  to  a  little 
windlass  placed  on  the  beam.  The  beam  receives  its 
up-and-down  movement  from  a  connecting  rod  attached 
to  a  crank  upon  the  axle  of  a  wheel  driven  by  a  belt 
from  a  small  steam-engine.  J 

After  boring,  the  chain  is  unfastened,  and  the  rods 
are  drawn  up  by  means  of  a  hemp  or  manilla  rope 
if  inch  (45  mm.)  in  diameter,  which  is  also  used  for 
working  the  sand-pump.  The  master  borer  can  per- 
form all  the  necessary  operations  while  sitting  in  front 
of  the  hole.  By  means  of  the  rope  a  he  can  work 
the  windlass  upon  which  the  chain  is  coiled,  and  by 
pulling  the  lever  b  he  can  throw  in  or  out  of  gear  the 

*  B.  u.  h.  Z.,  1890,  p.  205, 

f  lleports  and  Statistics  of  the  Mining  Department,  Victoria, 
Quarter  ended  March  31,  1891,  Dip  contrivance,  p.  28. 

J  Syroczynski,  "Note  sur  le  forage  canadien,"  Bull.  Soc. 
Ind.  Min.,  tome  iii.,  3°  Serie.  Saint-Etienne,  1889,  p.  1417. 


BORING.  135 

pulley  which  drives  the  drum  with  the  winding  rope,  and  so  raise 
or  lower  the  rods  or  the  sand-pump.  The  lever  c  actuates  a 
brake  which  enables  him  to  stop  the  machinery,  if  necessary,  and 
with  his  left  foot  he  can  press  upon  a  pedal  e,  and  so  regulate 
the  steam  valve,  and  alter  at  pleasure  the  speed  of  the  engine. 

FIG.  132, 


The  cord  d  works  a  second  steam  valve.  Two  other  workmen, 
one  at  the  bore-hole,  and  the  other  on  a  platform  33  feet  (10  m.) 
above  him,  are  shown  in  the  act  of  unscrewing  and  putting  away 
the  rods. 

During  the  actual  boring,  the  two  assistants  stand  at  the  hole 
and  turn  the  rods,  whilst  the  master  borer  regulates  the  blow  by 


136  ORE  AND  STONE-MINING. 

the  cord  a  which  commands  the  windlass,  and  the  cord  d  which 
controls  the  admission  of  steam. 

The  tower  or  derrick  is  about  50  feet  (15  to  16  m.)  high,  and 
1 6  feet  (5  m.)  square  at  the  base.  It  is  closed  in  with  planks. 
The  adjacent  space  required  for  the  steam-engine,  belts,  wheels, 
<kc.,  is  35  square  yards  (30  square  m.).  The  end  of  the  beam 
travels  about  20  inches  (50  cm.);  but  owing  to  the  inter- 
position of  the  sliding  joint  the  stroke  of  the  chisel  is  some- 
what less.  There  are  about  50  to  60  blows  a  minute.  After 
work  has  gone  on  for  a  time,  and  the  debris  begin  to  accu- 
mulate, the  rods  are  withdrawn  and  the  shell-pump  is  lowered 
by  the  rope.  It  is  a  cylinder  32  feet  (10  m.)  long,  with 
a  valve  in  the  bottom  ;  it  fills  itself,  it  is  drawn  up,  and  the  valve 
is  opened  to  discharge  the  sludge.  In  consequence  of  the  light- 
ness of  the  rods,  the  conicity  of  the  screw  joints,  and  the  skill  of 
the  workmen,  the  various  boring  operations  are  carried  on  with 
surprising  rapidity.  Scarcely  half  a  minute  is  required  for  un- 
screwing a  joint,  and  a  set  of  rods  650  feet  long  (200  m.)  is  drawn 
up  or  lowered  in  10  or  12  minutes. 

For  a  hole  1000  feet  (300  m.)  deep,  the  four  operations  of 
raising  the  chisel,  lowering  and  raising  the  shell-pump,  and 
again  lowering  the  rods  and  chisel,  do  not  require  more  than 
an  hour. 

Three  men  are  required,  of  whom  one  is  the  master  borer  and 
one  the  engineman.  Their  wages  do  not  exceed  10  florins  a  day, 
and  if  the  wages  of  the  smiths,  who  are  constantly  required,  are 
added,  the  total  cost  of  wages  per  day  will  be  from  15  to  16 
florins. 

The  initial  diameter  of  the  hole  varies  from  9!  inches  (0-25  m.) 
to  15!  inches  (0*40  m.)  in  loose  ground,  and  the  final  diameter  is 
4  inches  (0*10  m.).  The  hole  is  lined  with  tubes  throughout, 
they  are  made  of  welded  sheet-iron  screwed  together  and  perfectly 
watertight. 

The  successive  columns  of  tubes  of  the  lower  part  of  the  hole 
are  placed  one  within  the  other.  They  are  not  withdrawn  till  the 
hole  is  completed.  The  cost  of  the  plant  varies  from  8000  to 
10,000  florins,  including  a  12  to  15  h.-p.  steam-engine,  which, 
with  its  boiler,  comes  to  3500  florins.  To  this  must  be  added  the 
cost  of  the  tubing,  which,  according  to  the  diameter,  varies  from 
3  to  10  or  ii  florins  per  metre. 

The  boring  contractors  ask  from  15  to  25  florins  per  metre  for 
a  boring  estimated  to  be  1000  feet  deep  (300  metres),  plus  50  per 
cent,  of  the  petroleum  obtained  in  the  first  case,  or  30  per  cent, 
in  the  latter.  They  leave  the  tubes  necessary  for  preserving  the 
well,  provided  they  are  paid  one-half  of  their  value.  Contracts  are 
also  made  for  sinking  wells  at  50  florins  per  metre,  without  any 
interest  in  the  output. 

As  an  example  of  the  work,  a  well  was  bored  738  feet  deep 


BORING.  137 

(225  m.)  at  Wietrzno,  by  M.  Suszycki,  beginning  with  a  diameter 
of  i5f  inches  (0*40  m.)  and  ending  with  5^  inches  ('145  m.)  in  90 
days,  of  which  70  were  occupied  in  actual  boring.  The  average 
progress  was  10  feet  6  inches  per  day  (3*20  m.),the  maximum  32 
feet  (9*81  m.)  per  day.  Several  wells  have  been  bored  to  a  depth 
of  1500  feet  (over  450  metres)  at  Stoboda  Runzwoska.  Under 
some  exceptionally  favourable  circumstances  a  hole  475  feet 
(145  m.)  deep  was  bored  in  eight  days  with  140  hours  of  effective 
work. 

This  system,  therefore,  seems  suited  to  the  conditions  prevailing 
in  Galicia.  The  American  method  of  boring  with  the  rope,  which 
answers  in  Pennsylvania,  where  the  beds  are  nearly  horizontal, 
did  not  succeed  in  Galicia,  with  the  soft  Tertiary  rocks,  which 
often  dip  considerably.  As  regards  the  material  for  the  rods, 
wood  is  to  be  preferred  to  iron  in  Galicia.  Wooden  rods  are 
lighter  and  more  easily  manipulated  than  iron  rods,  besides  which 
they  are  more  easily  repaired,  a  matter  of  much  importance  in 
districts  far  from  foundries  and  engineering  shops. 

Driven  Wells. — Under  the  head  of  boring  by  percussion  may 
be  classed  the  process  of  making  driven  wells,  or  Abyssinian  tube- 
wells,  as  they  are  often  called  in  this  country.  A  tube  shod  with 
steel  is  rammed  down  by  a  heavy  weight,  raised  by  men  with 
ropes  passing  over  a  pulley,  and  then  allowed  to  fall  and  strike 
a  stop  clamped  to  the  tube.  The  tube  is  perforated  just  above 
the  shoe,  and  when  a  water-bearing  stratum  of  sand  or  gravel  is 
reached,  water  flows  into  it,  and  can  be  pumped  up.  This,  how- 
ever, is  a  special  process,  and  can  scarcely  be  considered  as  true 
mining. 


III.  BORING  BY  PERCUSSION  WITH  ROPE. 

American  System. — The  use  of  the  rope  for  boring  is  of  very 
ancient  date  in  China,  and  the  process  has  been  brought  to  great 
perfection  in  America  for  the  purpose  of  obtaining  petroleum  and 
natural  gas.  Within  the  last  few  years  the  American  system 
has  been  employed  at  Port  Clarence,  on  the  Tees,  for  obtaining 
brine.* 

The  first  operation  consists  in  erecting  the  drilling  rig,  consist- 
ing of  the  derrick,  steam-engine,  band-wheel,  walking  beam,  bull- 
wheel  and  sand-pump  reel. 

The  derrick  (Fig.  133)  is  a  framework  in  the  form  of  an  acute 
truncated  pyramid,  72  feet  high,  20  feet  by  20  feet  at  the  base, 
and  about  3  feet  square  at  the  top.  It  is  ingeniously  constructed 
of  2 -inch  plank,  without  any  large  or  heavy  pieces  of  timber,  and 

*  C.  Le  Neve  Foster,  "Some  Mining  Notes  in  1887,"  Trans.  Min.  Assoc. 
ami  7«.<f.,  Cornwall,  vol.  ii.  Truro,  1888,  p.  128. 


or  THE 


138 


ORE  AND  STONE-MINING. 


it  serves  to  carry  two  pulleys.  The  reason  of  its  height  is  to 
enable  the  driller  to  raise  the  whole  string  of  boring  tools  from 
the  hole  without  any  disjointing. 

The  engine  has  a  horizontal   cylinder,  8  inches  in  diameter, 
with  a  1 2-inch  stroke,  and  is  reckoned  to  be  of  15  horse-power. 

FIG.  133. 


By  means  of  a  belt,  power  is  transmitted  to  a  wooden  pulley 
(a)  called  the  band-wheel ;  this  is  provided  with  a  crank  (&),  and 
through  a  pitman  (c)  actuates  one  end  of  the  walking  beam  (d), 
26  feet  long.*  A  smaller  pulley  bolted  to  the  band- wheel  enables 
the  bull-wheel  (e)  to  be  driven  by  an  endless  rope,  and,  by  means 

*  The  figure  shows  the  pitman  taken  off  from  the  crank  pin. 


BORING.  139 

of  a  lever,  a  friction  pulley  (f )  can  be  brought  against  the  band- 
wheel  so  as  to  drive  the  sand  reel. 

These  are  the  principal  parts  of  the  rig.     In  addition  there  are 
wanted : — 

1 .  A  set  of  drilling  tools  (/*,  i,  j,  k.  I). 

2.  A  sand-pump  (m),  or  a  bailer. 

3.  A  rope  (g)  i  j  inch  in  diameter  for  lifting  the  tools. 

4.  A  rope  (g1)  J  inch  in  diameter  for  working  the  bailer  or 
the  sand-pump. 

FIG.  134.        FIG.  135.     FIG.  136.      FIG.  137.      FIG.  138.       FIG.  139. 


The  set  of  drilling  tools  consist  of  the  following  parts : — 


Rope  socket 
Sinker  bar 
Jars 

Auger  stem 
Bit  . 


Diameter, 
inches. 


Fig.  134  (and  k,  Fig.  133) 


135  (and  i 

136  (and/ 

137  (and  k 


Length, 
leec. 

3 

12 

6 


3* 


38  &  139  (and  /,  Fig.  133) 


Weight. 

Jbs. 

90 

400 

3co 

1050 

140 


140 


ORE  AND  STONE-MINING. 


The  jars  are  like  two  links  of  a  chain,  and  their  object  is  to 
enable  an  upward  blow  to  be  struck  if  the  bit  sticks ;  the  force  of 
this  upward  blow  is  increased  by  the  momentum  of  the  sinker 
bar. 

The  rope  socket  receives  the  end  of  the  boring  cable,  any  part 
of  which  can  be  connected  to  the  walking  beam  by  a  clamp  at- 
tached to  an  adjustable  link  called  the  temper  screw  (Fig.  140). 

FIG.  140.  FIG.  141.  FIG.  142. 


T 


The  bailer  is  a  wrought-iron  cylinder,  18  or  20  feet  long,  with  a 
valve  in  the  bottom,  which  opens  as  soon  as  its  projecting  stem 
touches  the  ground. 

1  The  sand-pump  (Fig.  141)  is  an  iron  cylinder,  5  feet  or  more  long, 
with  a  valve  in  the  bottom  and  a  piston.  When  it  is  lowered  to 
the  bottom  of  the  hole  the  piston  descends,  and  when  the  piston 
is  raised,  it  sucks  the  mud  and  debris  into  the  cylinder,  and  they 
are  retained  by  the  valve. 

When  the  hole  has  to  pass  through  loose  alluvial  soil,  a  drive- 
pipe  (a  a,  Fig.  350)  is  rammed  down  before  any  true  boring  begins. 
The  drive-pipe  is  made  of  steel,  J  inch  thick,  and  is  8J  inches  in 


BORING.  141 

diameter  internally.  It  is  supplied  in  lo-feet  lengths,  and  these 
are  connected,  like  gas-pipes,  by  screwed  sleeve  couplings,  14 
inches  long.  The  first  pipe  is  shod  with  a  sharp  steel  shoe. 

The  drive-pipe,  protected  at  the  top  by  an  iron  cap,  is  rammed 
down  by  a  heavy  wooden  block  (maul),  like  the  ram  or  monkey  of 
a  pile-driver,  working  between  two  vertical  guides,  and  length 
after  length  is  added  as  it  descends.  The  manner  in  which  the 
blow  is  given  will  be  plain  from  the  accompanying  diagram  (Fig. 
142),  in  which  the  guides  are  omitted.  The  maul  (a)  hangs  from  a 
rope  or  cable  which  passes  over  the  crown  pulley  (b)  at  the  top  of 
the  derrick  and  round  the  shaft  of  the  bull-wheel  (c).  Another 
rope  is  attached  to  the  crank  of  the  band-wheel  (d),  and  tied  to 
the  first  rope.  As  the  crank  revolves  it  pulls  the  cable  and  raises 
the  maul,  and  then  letting  the  cable  go  back,  causes  the  maul  to 
drop. 

When  the  pipe  has  been  rammed  down  until  the  shoe  is  driven 
into  hard  ground,  the  earth  inside  has  to  be  removed.  A 
swivel-head  is  attached  to  the  rope  in  place  of  the  block,  and  to  it 
are  screwed  the  sinker  bar,  or  the  auger-stem,  and  a  bit.  This  is 
worked  up  and  down  like  the  maul,  save  that  it  is  rotated ;  water 
is  poured  in,  and  soon  the  earth  is  knocked  up  into  mud.  The 
sand-pump  is  then  lowered  and  the  mud  brought  up.  These 
operations  are  repeated,  and  when  60  feet  have  been  cleared  in 
this  way  the  regular  boring  can  be  commenced. 

The  proper  cable  is  placed  upon  the  bull-wheel  shaft,  one  end 
brought  over  the  crown  pulley  and  attached  to  the  socket,  and  to 
this,  in  succession,  the  sinker  bar,  jars,  auger-stem,  and  bit.  I  will 
now  suppose  the  string  of  drilling  tools  to  be  hanging  in  the  hole. 
The  temper  screw  (Fig.  140,  and  n  Fig.  133)  is  clamped  to  the  cable, 
and  its  eye  hung  on  to  the  hook  at  the  end  of  the  walking  beam, 
the  cable  is  now  lowered,  and  the  string  of  tools  hangs  from  the 
walking  beam.  The  engine  is  set  in  motion,  and  as  the  band- 
wheel  revolves,  the  crank  turns  and  causes  the  walking  beam  to 
move  up  and  down,  and  the  bit  strikes  a  succession  of  blows  at 
the  bottom  of  the  hole.  The  driller  rotates  the  tool  by  turning 
the  clamp  round  and  round,  this  causes  the  slack  of  the  cable  to 
coil  around  the  part  below  the  temper  screw.  After  a  time  he 
turns  the  other  way,  and  the  coils  unwind  ;  this  process  is  re- 
peated over  and  over  again.  As  the  hole  deepens,  the  screw 
above  the  clamp  is  fed  out,  and  when  it  can  go  no  farther  the 
clamp  is  loosened,  and  shifted  higher  up  after  the  screw  has  been 
run  back. 

The  gravel,  sand,  and  mud  made  by  the  chipping  motion  of  the 
bit,  are  removed  by  the  sand-pump  lowered  and  raised  by  the 
special  rope  on  the  sand-pump  reel,  driven  by  the  friction  pulley. 
An  examination  of  the  small  fragments  drawn  up  in  the  sand- 
pump,  tells  the  driller  what  rocks  he  is  passing  through.  The 
two  operations,  drilling  and  clearing  out,  are  repeated  until  the 


142  ORE  AND  STONE-MINIXG. 

hole  has  reached  the  required  depth.  At  Port  Clarence  the  hole 
has  to  be  lined  with  a  steel  tube  (Fig.  350,  in  which  the  size 
of  the  tubes  is  greatly  exaggerated),  6f  inches  in  diameter  in- 
ternally;  for  the  first  150  feet  from  the  bottom  the  steel  is  half 
an  inch  thick,  then  five-sixteenths  of  an  inch  for  300  feet,  and 
the  remainder  quarter-inch  thick.  With  the  sleeve  couplings 
over  them,  they  just  pass  down  the  drive-pipe.  In  the  rock-salt 
and  in  the  600  feet  of  water-bearing  sandstone,  the  lining  pipe 
is  perforated  with  holes  one  inch  in  diameter,  and  1 2  inches  apart 
vertically.* 

By  the  American  system  the  cost  of  a  brine  well  at  Port 
Clarence,  1000  feet  deep,  including  the  rig  and  a  share  of  the 
boiler,  is  ^"1000,  and  it  is  drilled  in  three  weeks. 

Some  wells  bored  by  the  diamond  drill,  on  the  other  hand,  cost 
^3000  each,  and  took  three  months  to  make. 

The  American  system  presents,  therefore,  very  great  advan- 
tages, especially  in  the  case  where  holes  have  to  be  numerous,  and 
where  it  is  not  certain  how  long  a  well  will  retain  its  productive- 
ness. On  the  other  hand,  in  making  preliminary  explorations  of 
the  rocks  of  a  new  district,  the  diamond  drill  may  fairly  claim 
the  superiority,  because  it  furnishes  actual  cores,  showing  the  dip, 
which  give  a  better  idea  of  the  strata  than  pounded  fragments. 

Though  to  English  eyes  the  American  "rig"  appears  rather 
rough,  we  cannot  but  admire  its  effectiveness,  and  also  its  suit- 
ability in  the  case  of  petroleum  and  brine  wells.  The  "  rig  "  erected 
for  boring  is  utilised  for  pumping  when  the  hole  is  completed,  so 
that  there  is  no  unnecessary  expense  in  the  plant.  The  various 
parts  of  the  "  rig  "  are  very  simple  in  construction,  and  as  timber 
is  largely  used  in  place  of  metal,  repairs  can  be  done  by  the 
master  driller,  without  the  aid  of  fitter  or  foundry.f 

Mather  and  Platt's  System. — Another  method  of  boring 
with  the  rope  is  that  which  is  employed  by  Messrs.  Mather  and 
Platt.t  Its  peculiarities  are  a  flat  rope,  and  a  special  contrivance 
for  rotating  the  chisel. 

Fig.  143  represents  a  side  elevation  of  one  of  the  boring 
machines. 

A  A,  flat  hempen  rope  4^  inches  broad,  by  \  inch  thick ;  B  B, 
boring  head  ;  C,  drum  or  reel  for  the  rope,  driven  by  the  steam- 
engine  D  ;  E  E,  wooden  or  cast-iron  frame  ;  F,  guide  pulley  ;  G, 
flanged  pulley  carried  in  a  fork  on  the  top  of  the  piston-rod  of  a 
vertical  single-acting  steam-engine  shown  by  the  dotted  lines. 

*  For  the  process  of  obtaining  the  salt  see  Chapter  VI. 

•f  Many  of  my  figures  and  occasional  explanations  are  borrowed  from 
the  useful  Illustrated  Catalogue  of  the  Oil  Well  Supply  Co.,  Limited,  of 
Bradford  and  Oil  City,  Pennsylvania,  who  have  furnished  both  the  plant 
and  the  drillers  for  the  wells  bored  on  the  American  system  at  Port 
Clarence. 

t  W.  Mather,  "  On  Well-Boring  and  Pumping  Machinery,"  Proc.  Inst. 
Meek.  Eng.,  1869,  p.  278. 


BORING. 

FIG.  143. 


144 


ORE  AND  STONE-MINING. 


FIG.  144. 


BORING.  145 

J  is  a  clamp  by  which  the  rope  A  is  fixed  while  boring  is 
going  on. 

Steam  is  admitted  below  the  piston  (Fig.  144)  raising  the 
pulley  G ;  at  the  end  of  the  stroke,  the  exhaust  valve  is  opened, 
the  steam  escapes,  and  the  piston,  pulley,  rope,  and  boring  head  all 
drop.  The  exhaust  port  is  so  arranged  as  to  leave  a  cushion  of 
steam  which  prevents  the  piston  from  striking  the  bottom  of  the 
cylinder.  The  steam  and  exhaust  valves  are  worked  automatically 
by  tappets,  M  M,  actuated  by  the  piston-rod.  The  length  of  the 
stroke  can  be  varied  from  i  to  8  feet  by  shifting  these  tappets. 
The  usual  speed  is  24  blows  a  minute. 

The  boring  head  (Fig.  145)  forms  a  special  feature  of  Mr. 
Mather's  invention.  The  chisels  or  cutters  D  are  fixed  by  nuts 
in  the  cast-iron  block  C  ;  E  is  a  cylindrical  block  serving  as  a 
guide,  aud  F  is  a  second  or  upper  guide  which  assists  in 
effecting  the  rotation.  On  its  circumference  there  are  ribs 
which  catch  in  one  direction  ;  they  are  placed  at  an  inclination, 
like  segments  of  a  screw  thread  of  very  long  pitch.  Each 
alternate  plate  has  the  projecting  ribs  inclined  in  the  opposite 
direction,  so  that  one-half  of  the  bars  turn  the  rod  round  in 
rising,  and  the  other  half  turn  it  in  the  same  direction  during 
the  descent ;  but  they  simply  assist  in  producing  the  rotation 
which  is  mainly  secured  by  the  contrivance  represented  above  F. 
Two  cast-iron  collars,  G  and  H,  are  cottered  to  the  top  of 
the  bar  B,  and  their  deep  ratchet-teeth  are  set  exactly  in  line 
with  one  another.  J  is  a  movable  bush  sliding  upon  the  bar  B, 
and  attached  to  the  boring  rope  by  the  bow  K  and  a  short  piece 
of  chain. 

The  bush  J  has  ratchet-teeth  on  its  upper  and  lower  faces,  but 
the  upper  teeth  are  set  half  a  tooth  in  advance  of  the  lower 
ones.  During  the  ascent  of  the  rope,  the  bush  has  the  position 
shown  in  the  figure  ;  but  when  the  tool  strikes  the  blow,  the 
bush  descends,  and  the  centre  of  the  inclined  surface  of  each  lower 
tooth  of  J  strikes  the  point  of  a  tooth  of  G,  and  then  slides  down 
on  it,  twisting  J,  and  with  it  the  flat  rope,  to  the  extent  of  half  a 
tooth.  At  the  commencement  of  the  lift  the  bush  J  receives 
a  further  twist  of  half  a  tooth  by  coming  against  H.  The  flat 
rope  is  thus  twisted  altogether  to  the  extent  of  one  tooth,  and  in 
untwisting  it  turns  the  tool  a  like  amount ;  automatic  rotation  of 
the  cutters  is  thus  secured. 

P  (Fig.  143)  is  the  shell-pump,  or  sludger,  and  Q  is  an  overhead 
suspension  bar  by  means  of  which  it  is  brought  over  the  little 
table  R  in  the  tank  T.  The  screw  S  serves  to  raise  the  table  R 
until  the  pump  rests  upon  it,  and  on  knocking  out  a  cotter  in  the 
rod  which  supports  the  seating  of  the  bottom  valve,  the  sludge  is 
speedily  discharged. 

One  man  can  attend  to  all  the  operations  of  raising  and  lower- 
ing, changing  the  boring  tool  for  the  shell-pump  or  vice  versd, 

K 


i46  ORE  AND  STONE-MINING. 

FIG.  145. 


Elevation 


I 


BORING.  1 47 

and   regulating  the    boring.      Two   labourers   are   employed   to 
change  the  cutters  and  clear  out  the  shell-pump. 

Cores  may  be  cut  out  as  in  other  systems  of  boring,  and 
extracted,  so  as  to  show  the  nature  and  dip  of  the  strata.  As  the 
rope  is  flat,  cores  can  be  brought  up  without  any  twist. 

The  flat  rope  method  is  used  by  Messrs.  Mather  and  Platt  for 
holes  from  20  inches  to  45  inches  in  diameter.  In  the  case  of 
small  holes  from  which  no  cores  are  required,  they  now  adopt  the 
American  system  on  account  of  its  expeditiousness. 

From  what  has  been  said  it  is  very  evident  that  a  great  diversity 
of  practice  exists  in  making  bore-holes,  and  the  miner  may  have 
some  difficulty  in  making  up  his  mind  which  system  to  adopt  for 
any  given  purpose.  In  the  case  of  large  undertakings,  he  usually 
applies  to  some  firm  of  engineers,  who  by  long  and  constant  expe- 
rience in  their  art  are  able  to  guarantee  success. 

Surveying  Bore-holes. — It  is  often  assumed  by  boring  engi- 
neers that  the  holes  which  they  drill  are  perfectly  vertical ;  but 
experience  has  shown  that  this  is  not  always  the  case.  It  is, 
therefore,  important  to  have  some  means  of  measuring  the  devia- 
tion of  a  bore-hole  from  the  vertical,  and  surveying  its  exact  course. 
A  useful  instrument  for  this  purpose  is  Macgeorge's  clinograph.* 
It  consists  in  the  main  of  two  glass  bulbs,  the  upper  one  carrying 
a  plummet,  the  lower  one  a  magnetic  needle  ;  both  bulbs  are 
filled  with  gelatine.  When  hot  the  gelatine  is  liquid,  and  the 
plummet  and  the  needle  are  free  to  move  ;  when  the  gelatine  is 
cold  both  are  set  fast.  The  gelatine  simply  serves  as  a  clamp 
which  will  act  of  itself  after  a  certain  time. 

The  exact  construction  is  explained  by  Fig.  146.^  The  instru- 
ment consists  of  a  cylinder  terminating  in  a  short  neck 
and  a  bulb  at  the  bottom.  In  this  is  a  magnetic  needle  FIG.  146. 
attached  to  a  hollow  pear-shaped  glass  float,  which  will 
always  stand  upright  upon  its  pivot  and  so  enable  the 
needle  to  swing  round  without  touching  the  sides.  A 
smaller  glass  cylinder,  with  a  bulb  at  the  top,  is  inserted 
through  an  air-tight  cork  and  a  brass  capsule  at  the  upper 
end  of  the  large  one.  Its  lower  end  passes  into  a  cork, 
which  prevents  the  escape  of  the  float  of  the  needle. 
The  upper  bulb  contains  a  delicate  plummet  of  glass,  (2) 
with  diminutive  hollow  float  at  the  top  and  a  solid  ball 
at  the  bottom,  which  is  prevented  from  dropping  out  by  a  delicate 
grating.  It  is  carefully  adjusted  to  the  specific  gravity  of  the 
solidifying  fluid  which  fills  the  cylinders  and  bulbs,  and  is  so 
arranged  that  it  will  assume  a  vertical  position  whenever  it  is  free 
to  move. 

*  "The    Clinograph,"    Engineering,   vol.    xxxix.   (1885),  p.  260.     "The 
Diamond  Drill  Clinometer,"  Min.  Jour.,  vol.  liii.  (1883),  p.  1509. 
t  Brough,  Mine  Surveying,  p.  276. 


148  ORE  AND  STONE-MINING. 

In  order  to  make  use  of  these  dip-recorders,  or  clinostats,  as 
Mr.  Macgeorge  calls  them,  six  are  placed  in  a  bath  of  warm  water, 
which  is  heated  nearly  to  boiling.  In  the  meantime  a  brass 
cylinder  is  also  heated  by  filling  it  several  times  with  boiling 
water,  and  when  the  clinostats  have  been  inserted  one  after  the 
other  into  it,  it  is  lowered  into  the  bore-hole  and  allowed  to 
remain  there  for  two  or  three  hours.  By  this  time  the  gelatine 
will  have  set ;  the  brass  case  is  drawn  up  and  the  clinostats  are 
examined  one  by  one  in  a  special  instrument  designed  by  Mr. 
Macgeorge.  This  has  an  arrangement  for  placing  the  clinostat 
in  exactly  the  same  position  which  it  occupied  in  the  bore-hole, 
and  for  enabling  its  angle  of  inclination  and  its  magnetic  bearing 
to  be  measured  very  accurately.  The  mean  of  the  six  sets  of 
observations  is  then  taken  as  representing  the  correct  deviation. 

If  a  bore-hole  is  approximately  vertical,  and  the  strata  com- 
paratively cool,  the  brass  tube  containing  the  clinostats  may  be 
lowered  with  a  wire  rope ;  but  if  the  strata  are  hot  or  the  bore- 
hole somewhat  flat,  •J-inch  iron  pipe  is  employed  for  inserting 
the  brass  case.  Care  is  taken  to  interpose  a  distance  tube  of 
brass  between  the  case  and  the  pipes,  to  prevent  their  action  on 
the  magnets.  If  the  bore-hole  is  warm,  cold  water  is  forced  down 
the  pipe  so  as  to  flow  outside  the  case  with  the  clinostats,  and 
congeal  the  gelatine. 

If  observations  are  made  at  regular  intervals,  say  at  every  100 
feet,  the  path  of  the  bore-hole  can  be  traced  with  great  accuracy. 

The  apparatus  may  also  be  used  over  a  core  extractor  when  it 
is  necessary  to  ascertain  the  direction  and  amount  of  the  dip 
of  the  strata.  Macgeorge  employs  a  brass  tube  set  excentric- 
ally,  and  provided  with  a  bell-mouth  below.  This  receives  the 
end  of  the  core,  and  the  excentricity  of  the  tube  causes  pressure 
on  one  side  which  makes  the  core  break  off.  The  core-extractor 
contains  an  inner  tube,  slotted  from  end  to  end,  which  expands 
as  the  core  enters  it  and  nips  it  tightly. 

Mr.  Macgeorge  gives  numerous  instances  of  ascertained  deflec- 
tions of  bore-holes.  At  Scotchman's  United  mine,  Stawell,  Vic- 
toria (Figs.  147  and  148),  a  bore-hole  370  feet  deep,  put  down  with  a 
diamond  drill,  was  found  to  have  a  deviation  of  37  feet  3  inches. 
It  is  calculated  that  ^2311  would  have  been  saved  if  the 
path  of  the  drill  had  been  surveyed  before  the  driving  was  com- 
menced. At  the  Oriental  Company's  mine  a  bore-hole  turned 
out  to  be  60  feet  9  inches  out  of  its  proper  course  in  a  depth  of 
425  feet.  Similar  cases  of  deflection  have  been  noted  in  bore-holes 
made  in  Germany  both  by  the  diamond  drill,  and  by  the  percussive 
method. 

The  deviation  from  the  vertical  may  likewise  be  recorded  by 
Nolten's*  method,  which  depends  upon  the  etching  action  of 

*  P.  K.,  "The  Deviation  of  Bore-holes,"  Colliery  Guardian,  vol.  liii. 
(1887),  p.  775, 


BORING. 

FIGS.  147  &  148. 


149 


Section 


A,  shaft  ;  B,  supposed  position  of  the  bore-hole ;  A  B,  level 
driven  out  from  A  to  strike  the  bore-hole ;  C,  actual  position  of 
the  bore-holes ;  D,  E,  F,  G,  drivages  made  in  search  of  the  bore- 
hole. The  section  shows  that  if  the  bore-hole  had  been  continued 
to  a  depth  of  500  feet,  the  deviation  would  have  amounted  to  71; 
feet. 


150  ORE  AND  STONE-MINING. 

hydrofluoric  acid  upon  glass.  A  glass  cylinder  with  a  truly  flat 
bottom,  and  the  sides  at  right  angles  to  the  base,  is  partly  filled 
with  dilute  hydrofluoric  acid,  put  into  a  case,  carefully  lowered 
into  the  hole,  and  allowed  to  remain  there  for  half  an  hour.  The 
acid  eats  into  the  glass,  which  is  then  drawn  up.  The  line  of  etching 
records  what  was  the  horizontal  plane  when  the  cylinder  was  in 
the  bore-hole,  and  the  angle  between  it  and  the  flat  bottom 
measures  the  deviation  from  the  vertical. 

Trouve  *  has  designed  an  electric  lamp  with  a  mirror  set  at  an 
angle  of  45°,  which  is  lowered  into  the  bore-hole  and  gives  an 
image  of  the  strata.  The  observer  at  the  surface  examines  this 
image  by  means  of  a  telescope. 

*  Eny,  Min.  Jour.,  vol.  1.  (1890),  p.  483. 


CHAPTER  IV. 

BREAKING  GROUND. 

Hand  tools:  Shovel,  crow-bar,  pick,  wedge,  saw  ;  tools  for  boring  holes. — 
Excavating  machinery. — Transmission  of  power  by  air,  water,  and 
electricity. — Diggers,  dredges,  rock-drills,  groove-cutters,  tunnellers. 
—Explosives  and  blasting. — Driving  and  sinking. — Fire-setting. — 
Excavating  by  water. 

HAND  TOOLS. — The  kinds  of  ground  in  which  mining 
operations  have  to  be  carried  on  vary  within  the  widest  limits, 
from  loose  quicksands  to  rocks  which  are  so  hard  that  the  best 
steel  tools  will  scarcely  touch  them. 

Shovel. — Loose  ground  can  be  removed  with  the  shovel. 
Probably  some  of  the  first  diggin'g  tools  were  merely  pointed  sticks ; 
indeed,  the  Burmese  workman  of  to-day  uses  an  iron-shod  stake 
for  sinking  oil-wells.  Shovels  vary  a  good  deal  in  shape  and 
make,  according  to  the  special  purposes  for  which  they  are 
employed,  and  also  according  to  the  fancies  of  the  users.  The 
plate  or  blade  is  usually  made  of  steel,  and  it  is  pointed  in  front, 
so  as  to  penetrate  easily  into  the  earth  or  stone  that  has  to  be 
moved.  A  wooden  handle  is  attached  to  it  by  a  socket  or  two 
long  straps.  The  handle  is  often  made  of  ash,  and  is  usually 
short,  but  in  Cornwall  and  Devon  a  long  one  is  preferred. 

In  dealing  with  clay  and  sticky  earth  it  is  advisable  to  have  the 
plate  as  smooth  as  possible ;  the  shovel  with  a  hollow  underneath 
at  the  junction  with  the  socket  is  objectionable  for  material  of 
this  kind,  because  the  cavity  becomes  choked,  and  the  tool  is  then 
less  easily  wielded.  Even  the  projecting  rivets  sometimes  used  to 
attach  the  socket  to  the  plate  cause  a  slight  hindrance,  which 
means  unnecessary  waste  of  power.  Shovels,  like  all  other  hand 
tools,  should  be  made  as  light  as  possible,  consistent  with  strength, 
in  order  to  relieve  the  workmen  from  the  unprofitable  labour  of 
moving  useless  dead  weight. 

In  the  special  case  of  peat,  sharp  spades  are  employed,  which 
cut  through  the  woody  fibres,  and  furnish  lumps  or  sods  of  con- 
venient form  for  drying  and  for  subsequent  use  as  fuel. 

When  it  is  desired  to  separate  the  larger  stones  from  all  finer 
material,  a  fork  with  several  prongs  is  a  convenient  tool. 

Crowbar. — This  tool  is  an  iron  lever ;  it  is  used  for  prising  off 
blocks  of  stone,  and  for  shifting  them  after  they  have  been 
detached. 


ORE  AND  STONE-MINING. 


Pick. — What  is  called  fair,  soft,  or  easy  ground,  such  as  clay, 
shale,  decomposed  clay-slate,  and  chalk,  requires  the  use  of  the 
pick  and  the  shovel ;  the  pick  breaks  up  the  ground,  and  the  shovel 
serves  to  shift  it.  The  pick  is  a  tool  of  variable  form,  according 


FIG.  149. 


Q 


to  the  material  operated  on.  Thus  there  are  the  navvy's  pick,  the 
poll-pick,  with  a  point  and  a  striking  end  (Fig.  149),  and  numerous 
varieties  of  the  double-pointed  pick  (Fig.  150),  the  special  tool  of 
the  collier,  but  also  largely  used  in  ore  and  stone  mining.  The 


FIG.    151. 


FIG.  152. 


B 


blades  of  picks  are  made  either  of  iron  with  steel  tips,  or  else 
entirely  of  steel.  The  latter  is  preferable,  as  it  lasts  so  much 
longer.  The  tip  may  be  a  point  or  a  chisel  edge.  The  blade  is 
usually  set  at  right  angles  to  the  hilt  or  handle  ;  but  at  the  under- 


BKEAKING  GROUND. 


153 


ground  stone  quarries  at  Bath  and  Weldon  it  is  oblique,  as  shown 
in  Fig.  151.  The  object  of  this  form  is  to  enable  the  miner  to  cut 
well  into  the  corners  of  the  deep  horizontal  groove  required  for 
excavating  the  stone.  This  pick  weighs  5  Ibs. 

Blunted  picks  are  sharpened  by  having  the  points  heated  in  the 
blacksmith's  fire,  hammered  to  the  proper  shape  and  tempered. 
In  order  to  save  the  trouble  of  carrying  a  large  supply  of  tools, 
the  blade  may  be  made  separable  from  the  hilt,  and  the  miner 
takes  the  blades  only  to  the  smithy  when  they  are  worn.  Fig.  152 
shows  a  pick  of  this  description  used  at  Mansfeld. 

Two  well-known  forms  of  pick  with  separate  blades  are  the 
"Acme"  and  the  "Universal"  of  the  Hardy  Patent  Pick 
Company. 

The  Acme  (Fig.  153)  is  a  pick  used  for  "  holing,"  or  cutting  a 
groove  in  a  soft  rock,  in  which  case  it  is  advisable  to  have  the  tool 


FIG.  153. 


A 


FIG.  154. 


as  narrow  as  possible,  in  order  to  avoid  the  unnecessary  work  which 
a  broad  eye  would  occasion.  The  blade  is  made  with  a  notch  at 
the  top,  and  a  wedge  makes  it  fast  to  the  head ;  blades  vary  from 
i-J  to  3  Ibs.  in  weight. 

The  Universal  (Fig.  154)  has  the  large  end  of  the  shaft  or  handle 
fitted  with  a  cast  steel  or  malleable  iron  socket;  the  small  end  is  put 
through  the  eye  of  the  blade,  which  becomes  firmly  fixed,  because 
the  socket  and  eye  are  carefully  made  to  gauge.  By  striking  the 
small  end  of  the  handle  on  the  ground  the  blade  is  loosened  and 
removed.  Blades  of  various  shapes  may  be  fixed  upon  the  same 
handle,  which  is  sometimes  an  advantage  in  remote  districts. 

The  handles  ("  hilts  "  or  "  shafts  ")  are  commonly  made  of  ash 
or  hickory.  In  Australia  and  New  Zealand  the  wattle  furnishes 
a  light,  tough,  elastic,  and  durable  wood  for  the  handles  of  picks 


154  OEE  AND  STONE-MINING. 

and  other  tools.     One  of  the  best  descriptions  is  the  Golden  Green 
Wattle  (Acacia  decurrens,  var.  mollis). 

Wedge. — When  the  ground,  though  harder,  is  nevertheless 
"  jointy,"  or  traversed  by  many  natural  fissures,  the  wedge  comes 
into  play.  The  Cornish  tool  known  as  a  gad  is  a  pointed  wedge 
(Fig.  155).  The  so-called  "pick  and  gad  "  work  con- 
sistsin  breaking  away  the  easy  ground  with  the  point 
of  the  pick,  wedging  off  pieces  with  the  gad,  driven  in 
by  a  sledge  or  the  poll  of  the  pick,  or  prising  them  off 
with  the  pick  after  they  have  been  loosened  by  the  gad. 
The  Saxon  gad  is  held  on  a  little  handle,  and  is 
struck  with  a  hammer.  It  is  used  like  the  Cornish 
gad  for  wedging  off  pieces  of  jointy  ground,  and  in 
former  days  even  hard  rocks  were  excavated  by  its 
aid.  The  process  consisted  in  chipping  out  a  series  of  parallel 
grooves,  and  then  chipping  away  the  ridges  left  between  them. 
As  a  method  of  driving  levels  or  sinking  shafts,  this  process  is 
naturally  obsolete ;  but  it  is  useful  on  a  small  scale  for  cutting 
recesses  (hitches)  for  fixing  timber,  for  dressing  the  sides  of  levels 
or  shafts  before  putting  in  dams,  and  for  doing  work  in  places 
where  blasting  might  injure  pumps  or  other  machinery. 

Saws. — Freestone  is  sometimes  excavated  by  sawing.  The 
saws  are  6  or  8  feet  long,  and  i  foot  wide.  The  wooden  handle 

can  be  fixed  so  that  no  part 
FIG.  156.  projects  above  the  saw  when 

ft       ->        the  tool  is  used  close  to  the 

-  roof  (Fig.  156). 

Tools  used,  for  Boring 
and  Blasting. — We  now  come 
to  hard  ground ;  and  in  this 
class  we  have  a  large.propor- 
tion  of  the  rocks  met  with  by  the  miner,  such  as  slate  of  various 
kinds,  hard  grit  and  sandstone,  limestone,  the  metamorphic  schists, 
granite,  and  the  contents  of  many  mineral  veins. 

Hocks  of  this  kind  are  attacked  by  boring  and  blasting.  The 
tools  employed  are  the  auger,  jumper,  or  borer  (drill),  hammer  or 
sledge  (mallet,  Cornwall),  scraper  and  charger,  tamping  bar  or 
stemmer,  pricker  or  needle,  claying  bar  and  crowbar. 

Augers. — At  English  gypsum  mines  a  tool  resembling  the  car- 
penter's shell-auger  is  regularly  used  for  boring  holes  for  blasting. 
It  is  worked  by  a  cross  handle,  and  makes  a  hole  ij  inch  in 
diameter.  Boring  is  done  in  the  bituminous  limestone  of  Seyssel 
by  screw-augers  in  a  similar  manner. 

Elliott  Drill. — Screw-augers  mounted  upon  stands  are  common. 
Fig.  157  represents  the  Elliott  drill,  which  consists  of  an  auger 
inserted  into  a  socket  upon  a  feed-screw  c,  which  works  upon  a 
worm-wheel  a,  held  fast  in  a  ring,  when  the  screw  clamp  b  is 
tightened.  On  moving  a  ratchet  brace  backwards  and  forwards, 


BREAKING  GROUND. 


155 


c  is  turned  round,  carrying  the  auger  with  it,  and  when  the  worm- 
wheel  is  tight,  it  advances  slowly  at  the  same  time.  If  a  very 
hard  piece  of  rock  prevents  the  penetration  of  the  auger,  the 
worm-wheel  slips  in  the  ring,  and,  by  suitably  arranging  the 
tightness  of  the  clamp  6,  the  machine  can  be  made  to  accommo- 
date its  advance  to  the  nature  of  the  rock. 

The  drill  itself  is  made  of  a  bar  of  twisted  steel,  which  clears 
itself  of  the  debris  to  a  certain  extent ;  when  it  has  penetrated  as 
far  as  it  will  go,  the  clamp  is  loosened,  enabling  the  feed- 
screw to  be  drawn  back  rapidly  without  rotating  at  all.  A  longer 
drill  is  put  in,  and  work  continued. 

The  light  frame  or  standard  is  made  in  two  halves,  and  by 
shifting  a  pin  its  length  can  be  altered  to  suit  the  height  of  the 


FIG.  157. 


FIG.  158. 


working  place,  whilst  the  final  tightening  is  done  by  a  screw  at 
the  bottom. 

Ratchet  Drill. — Where  even  more  simplicity  is  required,  a  self- 
feeding  ratchet  drill  can  be  employed,  with  a  piece  of  timber  set 
up  in  the  working  place  as  an  abutment.  An  auger  is  inserted 
into  a  socket  upon  a  feed-screw  a  (Fig.  158),  working  in  the  nut  b, 
attached  to  a  long  sheath.  When  the  ratchet  handle  c  is  worked,  a 
revolves  and  at  the  same  time  advances  from  the  feed-nut,  carrying 
the  auger  with  it.  The  sheath  is  prevented  from  turning  by 
putting  the  eye  of  a  pin  over  one  of  the  projecting  pegs  at  the  rear 
end,  and  allowing  the  pin  to  be  brought  up  by  the  first  twists  against 
the  piece  of  timber.  For  enabling  the  feed-screw,  after  it  has 
advanced  to  its  full  length,  to  be  quickly  returned  into  the  sheath, 
the  Hardy  Patent  Pick  Company  sometimes  use  Stayner's  Patent 


'56 


ORE  AND  STONE-MININC4. 


7/<s;v 
; 


O.i. 


, v. . 

FIG.  159.      FIG.  161.     FIG.  160.     FIG.  162.    FIG.  163. 


BREAKING  GROUND.  157 

Split  Nut,  instead  of  an  ordinary  nut;  when  the  split  nut  is 
loosened,  the  feed-screw  can  be  moved  back  without  loss  of  time 
in  turning. 

These  augers  worked  by  hand  will  do  good  work  in  moderately 
hard  ground,  such  as  tough  shale,  slate,  and  even  sandstone. 

Jumper. — The  simplest  tool  for  boring  holes  by  percussive 
action  is  the  jumper,  a  bar  of  iron  tipped  with  steel,  forged  into 
a  chisel-shaped  edge.  It  is  struck  against  the  rock,  and  turned 
a  little  at  each  blow,  and  in  this  way  chips  out  a  cylindrical 
hole. 

Fig.  159  represents  the  jumper  used  in  the  lead-bearing  sand- 
stone at  Mechernich,  made  of  a  bar  of  iron  |  inch  in  diameter, 
and  7  to  10  feet  in  length.  As  the  rock  is  soft,  the  cutting  edge 
can  be  made  wide  and  sharp.  The  exact  angle  of  the  actual 
cutting  edge  of  a  jumper  which  I  measured  was  42° ;  the  final 
sharpening  is  done  with  a  file.  At  the  open  workings  for  iron- 
stone in  Northamptonshire,  the  edge  comes  to  a  point  in  the 
middle  (Fig.  160). 

The  jumper  used  in  the  Festiniog  slate  mines  (Fig.  161)  has  a 
swelling  in  the  middle,  and  both  ends  are  sharpened ;  the  short 
end  serves  for  beginning  a  hole,  the  large  one  for  completing  it. 
The  ordinary  sharpening  is  done  by  heating  the  end  red-hot,  and 
filing  it  to  the  desired  form  while  the  jumper  is  held  in  a  vice.  It 
is  allowed  to  cool  gradually,  and  then  is  heated  again  in  the  forge, 
hardened  in  water  and  tempered. 

The  jumper  for  boring  holes  at  any  angle  in  the  rock-salt  of 
Cheshire  has  a  swelling  in  the  middle,  and  tapers  gradually  to 
each  end. 

The  jumper  of  the  Cleveland  ironstone  miner  (Fig.  162)  has  the 
swelling  at  one  end,  and  will  bore  holes  at  any  angle.  Like  the 
Festiniog  tool,  it  is  sharpened  by  being  hammered  into  shape,  and 
finally  filed  when  hot. 

Borers. — When  the  rocks  are  harder,  and  also  in  situations 
where  a  jumper  cannot  be  wielded,  the  miner  must  have  recourse 
to  the  borer  or  drill,  which  is  simply  a  steel  chisel  (Fig.  163). 

The  steel  is  brought  to  the  mine  in  the  form  of  round  or 
octagonal  bars,  and  is  cut  up  by  the  mine-smith  into  pieces  of 
the  required  length ;  one  end  is  forged  into  a  chisel-shaped 
edge,  the  exact  shape  and  degree  of  sharpness  varying  according 
to  the  hardness  of  the  rock.  For  hand-drilling  the  steel  is  usually 
J  inch  to  i  inch  in  diameter,  but  f  inch  or  even  J  inch  steel  is 
sometimes  used.  The  old  plan  of  making  the  drill  of  iron,  and 
welding  on  a  piece  of  steel  for  the  cutting  edge  (bit),  is  almost 
extinct  in  this  country. 

The  shape  of  the  bit  of  the  hand  drills  used  at  Minera  mine, 
North  Wales,  is  shown  in  Figs.  164  and  165,  the  angle  of  the 
edge  being  84°  The  drills  used  with  the  compressed  air  machines- 
at  Minera  are  rather  blunter  than  a  right  angle.  At  a  limestone 


158 


OKE  AND  STONE-MINING. 


FIGS.  164  &  165. 


quarry,  near  the  mine,  the  drills  have  two  cutting  edges  arranged 
in  step-fashion. 

Drills  for  hard  rocks  are  sharpened  entirely  at  the  forge;  the 
cutting  edge  is  hammered  into  the  desired  shape  on  the  anvil 

while  red-hot,  and  then  hard- 
ened to  suit  the  particular 
requirements  of  i/he  user.  In 
many  cases  the  desired  temper 
is  obtained  by  plunging  the 
tool  when  at  a  blood-colour 
into  cold  water,  and  allowing 
it  to  remain  there  ;  but  for 
soft  rock  the  tool  will  work 
efficiently  after  the  hardness 
has  been  reduced  by  anneal- 
ing. In  the  case  of  slate  the 
smith  heats  the  end  of  the 

jumper  to  blood-colour,  and  just  dips  the  edge  into  water  for  a 
few  seconds.  He  now  watches  its  colour  as  it  cools  down,  and 
stops  the  annealing  or  tempering  action  by  plunging  the  tool  into 
cold  water  when  a  certain  shade  of  blue  has  been  reached.  Some 
smiths  rub  the  edge  of  the  tool  upon  a  piece  of  board  with  a  little 
sand,  in  order  to  be  able  to  follow  the  changes  of  hue  with  pre- 
cision. 

Before  the  introduction  of  machines,  as  many  as  fifty  drills 
were  sometimes  blunted  in  boring  a  hole  2  feet  deep  by  hand  at 
an  iron  pyrites  mine  in  Carnarvonshire.  This  is  an  exceptional 
case,  but  nevertheless  the  importance  of  having  a  good  smith  at  a 
mine  where  much  sharpening  has  to  be  done  cannot  be  over- 
estimated. 

A  tool  called  a  "bull  "is  employed  in  boring  holes  in  tough 
haematite  and  tough  clay  in  some  districts.  It  is  a  bar  pointed  at 
one  end  and  provided  with  an  eye  at  the  other.  It  is  driven  into 
the  ore  with  a  sledge,  and  by  putting  another  bar  through  the 
eye  it  can  be  withdrawn  without  difficulty.  There  is  practically 
no  difference  between  it  and  the  claying  bar  (Fig.  172). 

Hammers. — The  hole  is  bored  by  striking  the  drill  with  a 
hammer  or  sledge,  and  turning  it  after  each  blow.  Boring  is 
said  to  be  single-handed  if  the  miner  holds  the  drill  in  one  hand 
and  wields  the  hammer  with  the  other ;  whilst  it  is  called  double- 
handed  when  one  man  strikes  and  another  turns.  Sometimes 
there  are  two  men  to  strike,  one  after  the  other,  whilst  a  third 
man  turns  the  drill. 

In  starting  a  hole  a  short  drill  is  chosen,  and  longer  ones  are 
taken  as  the  hole  is  deepened;  the  smith  is  careful  to  make 
the  cutting  edges  (bits)  diminish  slightly  in  width  as  the  borers 
increase  in  length,  because  the  hole  gradually  decreases  in 
diameter  as  the  tool  wears.  The  bore-hole  is  therefore  not  a  true 


BREAKING  GROUND. 


159 


FIG.  1 66. 


cylinder,  but  a  frustum  of  a  very  elongated  cone.  It  may  even 
happen  that,  owing  to  the  manner  in  which  the  miner  has  turned 
his  borer,  the  section  of  the  hole  forms  a  triangle  and  not  a  circle. 
The  deep  holes  bored  for  quarrying  granite  invariably  become 
triangular  after  a  small  depth  has  been  reached ;  but 
the  sides  are  straighter  and  the  corners  less  sharp 
than  shown  in  Fig.  166,  which  represents  a  shape 
sometimes  seen  in  slate. 

Boring  hammers  and  sledges  are  almost  universally 
made  of  steel ;    but    until  comparatively  lately  iron 
hammers   with  a  steel  face  or  pane  were    common, 
and  even  in  some  districts  the  head  of  the  hammer  was  made 
entirely  of  iron,  which  was  worn  into  a  deep  hole  by  the  end  of 
the  hard  steel  drill. 

The  hammers  for  single-handed  boring  vary  in  weight  from 
2  to  6  or  7  Ibs.  The  hammers  used  by  the  Festiniog  miners  and 
quarrymen  weigh  from  5^-  to  7  Ibs  (Fig.  167).  The  handle  is  10  to 
1 2  inches  long.  In  some  districts  the  head  is  curved  slightly,  so 

FIG.  167. 


as  to  follow  the  circle  in  which  it  is  swung.  A  good  miner  should 
be  able  to  wield  the  hammer  with  either  hand,  because  he  may 
have  to  put  in  a  hole  close  to  either  side  of  a  level  or  stope ;  he 
should  also  be  able  to  strike  upwards,  because  occasions  arise 
where  a  hole  bored  in  this  manner  will  be  far  more  advantageous 
for  removing  rock  than  one  bored  downwards. 

The  double-handed  boring  hammer  or  sledge  (mallet,  Cornwall) 
weighs  from  6  to  10  Ibs.  or  more,  and  the  handle  is  2  feet  or  more 
long  (Fig.  1 68).  If  swung  round  by  good  hands,  it  strikes  a  very 
powerful  blow. 

In  a  rock-boring  competition  in  Cornwall*  a  few  years  ago,  three 
men  from  Tincroft  mine,  two  striking  and  one  turning,  bored  a 
hole  13  inches  deep  in  hard  granite  in  6  minutes  43  seconds, 

*  The  West  Briton,  Aug.  9,  1888. 


UNI  V 


OF  THE 


i6o 


ORE  AND  STONE-MINING. 


making  91  blows  per  minute;  three  men  from  Dolcoath  bored 
i2|  inches  in  7  minutes  18  seconds,  making  130  blows  per  minute, 
whilst  a  like  number  from  Carn  Brea  bored  1 2f-  inches  in  8  minutes 
with  117  blows   per   minute.      The    Tincroft   men 
FIG.  1 68.     slung  the  sledge  round,  the  others  did  not.     The 
{f*^^     drills  used  were  made  of  steel,  i  inch  in  diameter ; 
but  there  was  no  restriction  as  to  the  size  or  shape 
of  the  bit.     Of  course  these  results  are  simply  use- 
ful as  showing  what  can  be  done  under  very  favour- 
able circumstances,  and  for  a  very  short  time. 

If  the  hole  is  directed  downwards,  the  miner 
throws  in  a  little  water  and  bores  the  rock  wet.  A 
ring  of  rope  or  leather  put  round  the  drill  prevents 
the  water  from  splashing  him.  The  water  serves 
three  purposes :  it  renders  the  boring  easier  by 
holding  the  fine  particles  in  suspension  instead  of 
their  lying  at  the  bottom  of  the  hole  j  it  keeps  the 
tool  cool,  which  makes  it  last  longer,  and  it  prevents 
dust,  which  would  otherwise  be  breathed  by  the 
miner  and  tend  to  cause  lung  disease.  In  places 
where  miners  are  paid  by  the  depth  bored,  a  higher 
price  per  inch  is  sometimes  given  for  holes  bored  dry  than  for 
those  bored  wet.  The  depth  bored  varies  with  the  rock,  and  the 
nature  of  the  excavation ;  but  in  driving  levels  in  the  ordinary 
way  by  hand,  the  depth  is  commonly  from  18  inches  to  3  feet. 

Scraper. — From  time  to  time  the  miner  draws  out  the  sludge 
with  a  "  swab-stick,"  or  the  dust  with  a  scraper.  The  former  is 
a  wooden  stick  with  the  fibres  at  one  end  frayed  into  a  sort  of 
mop  ;  the  latter  is  a  little  disc  at  the  end  of  a  metal  rod.  For 
removing  small  bits  of  stone  a  rude  syringe,  called  a  "gun,"  is 
occasionally  employed ;  it  is  a  piece  of  gas -pipe,  or  an  .old  gun- 
barrel,  fitted  with  an  iron  piston  made  tight  by  hemp.  It  also 
serves  for  flushing  out  "  uppers." 

The  accessory  tools  required  subsequently  for  charging  the  hole, 
are  the  tamping-bar  or  stemmer,  pricker  or  needle,  charging-spoon, 
cartridge  stick,  and  claying-bar. 

Tamping-bar. — The  tamping-bar  or  stemmer  is  a  rod  of  wood, 
iron,  copper  or  bronze,  or  iron  shod  with  copper,  and  it  is  used 

FIG.  169. 


for  ramming  in  clay,  pounded  slate,  sand,  or  the  dust  from  the 
bore-hole  or  other  suitable  material  upon  the  explosive,  and  so 
causing  a  resistance  sufficient  to  make  the  gases  generated  by  the 
blast  rend  the  rock  in  the  manner  required. 

The  tamping-bar  (Fig.  169)  is  sometimes  a  plain  metal  rod,  with 
a  little  swelling  at  the  striking  end,  but  often  a  groove  is  left  to 


BREAKING  GROUND.  161 

lessen  the  chance  of  injuring  the  fuse ;  the  use  of  this  groove  is 
more  apparent  when  the  pricker  is  employed. 

Pricker. — The  pricker  or  needle  (Fig.  170)  is  a  slender  tapering 
rod  of  copper  or  bronze  with  a  ring  at  the  large  end.     It  is  used 


FIG.  170. 

-A.  e" 


for  maintaining  a  hole  in  the  tamping  through  which  the  charge 
can  be  fired  by  a  squib,  rush  or  straw. 

Charging-spoon.  — •  The  charging-spoon  is  a  hollow  half- 
cylinder  of  copper  or  zinc,  at  the  end  of  a  copper  or  wooden  rod, 
which  is  used  for  introducing  loose  gunpowder  into  holes  which 

FIG.  171. 


are  more  or  less  horizontal.  The  scraper  and  spoon  are  often 
combined  (Fig.  171).  In  the  Festiniog  slate  mines,  a  copper  tube 
5  feet  long,  with  an  expanded  mouth,  is  sometimes  used  for  putting 
a  second  charge  of  gunpowder  to  the  bottom  of  a  hole  which  has 
simply  produced  a  rent,  without  severing  the  block  of  slate  from 
the  working  face. 

Under  the  Coal  Mines  Regulation  Act  of  1887,  prickers, 
scrapers,  chargers  and  stemmers  must  not  be  made  of  iron  or  steel ; 
the  Metalliferous  Mines  Act,  187 2,  likewise  prohibits  iron  or  steel 
prickers,  but  allows  iron  stemmers,  provided  they  are  not  used  in 
the  early  part  of  the  operation  of  tamping. 

Cartridge  Stick. — The  cartridge  stick  is  a  smooth  cylinder  of 
wood,  around  which  paper  is  bent  in  order  to  make  cases  for 
holding  gunpowder  or  the  tamping  material,  when  these  have  to 
be  inserted  into  holes  which  have  a  very  decided  upward  inclina- 
tion. The  paper  is  fastened  by  a  little  pitch  softened  in  the 
miner's  candle.  One  advantage  of  cartridges  for  all  holes  is  the 
absence  of  danger  from  grains  sticking  to  the  sides ;  when  powder 
is  put  in  loose,  a  premature  explosion  may  happen  from  such 
grains  being  ignited  during  the  process  of  tamping  and  conveying 
fire  to  the  charge. 

FIG.  172. 


Claying -bar. — The  claying-bar  (Fig.  172)  is  a  smooth  rod  of 
steel  a,  expanded  at  one  end  into  an  eye  c.  It  was  used  formerly 
for  lining  wet  holes  with  clay,  and  so  rendering  them  temporarily 


l62 


ORE  AND  STONE-MINING. 


watertight,  and  fit  for  holding  a  charge  of  gunpowder.  Lumps 
of  clay  were  put  into  the  wet  hole,  and  the  claying  iron  was  driven 
in  by  blows  on  the  head  b,  forcing  the  clay  into  every  fissure.  By 
putting  an  iron  bar  through  the  eye,  it  could  easily  be  twisted  and 
withdrawn.  Nowadays  wet  holes  are  almost  invariably  charged 
with  some  nitro-glycerine  explosive,  and  the  claying-bar  is  rarely 
required. 

Rending  Holes. — Where   a  stone  can  be  made  to  rend  along 
certain  lines,  cost  may  be  saved  by  shaping  the  holes  so  as  to  start 


FIG.  173. 


FIG.  174. 


FIG.  175. 


the  rifts  in  the  desired  directions.  This  is  the  principle  of  the 
Knox*  system  of  blasting  employed  at  the  sandstone  quarries  of 
Portland,  Conn.,  and  elsewhere  in  the  United  States.  A  round 
hole  (Fig.  173)  is  drilled  by  hand  or  by  machine,  and  then  two 
V-shaped  grooves  (Fig.  174)  are  cut  down  with  a  reamer  (Fig. 
175)  in  the  line  of  the  proposed  rift.  The  tool  I 
found  in  use  at  Berea,  Ohio,  is  slightly  different 
in  shape,  but  acts  in  the  same  way.  The  hole, 
when  fired,  produces  a  crack  or  rift  in  the  direction 
AB.  Several  holes  may  be  bored  in  a  line  if  neces- 
sary, and  fired  simultaneously  by  electricity.  The 
Githen  system,  lately  adopted  by  the  Ingersoll-Ser- 
geant  Bock  Drill  Company,  goes  a  step  further ;  for 
machine  drills  are  now  being  made  which  will  bore 
holes  with  an  elongated  section  in  one  operation. 

USE  OF  MACHINERY  FOR  BREAKING 
GROUND. — One  of  the  greatest  improvements  in 
the  art  of  mining  during  the  last  quarter  of  a  cen- 
tury has  been  the  introduction  of  machines  instead 
of  human  power,  for  performing  some  of  the  most 
laborious  work  in  mining  ;  the  mine-owner  is  able 
to  have  work  done  more  quickly  and  more  cheaply, 
and  the  working  miner  is  relieved  from  severe  toil 
under  unfavourable  conditions. 

The  power  may  be  generated  on  the  spot,  or  can 
be   transmitted  underground   from    prime   movers 
on  the  surface. 

As  means  of  generating  power  on  the  spot  we  may  turn  to 
steam,  water,  or  petroleum. 

*  Saunders,    "Dimension    Stone    Quarrying.— The    Blasting  Process." 
Tram.  Ainer.  ,Soc.  C.K,  vol.  xxv.  (Nov.  1891),  p.  504. 


BREAKING  GROUND.  163 

Though  boring  machines  in  open  quarries  are  often  worked  by 
steam  supplied  from  small  boilers  which  can  be  moved  about  on 
trucks,  appliances  of  this  kind  are  out  of  the  question  in  most 
underground  workings,  on  account  of  the  nature  and  small  size  of 
the  excavations,  the  inconvenience  and  danger  caused  by  the 
fire  and  heat,  and  the  trouble  of  getting  rid  of  the  products  of 
combustion  and  of  the  exhaust. 

Power  can  be  obtained  by  bringing  down  water  in  pipes  from 
the  surface,  or  from  overlying  strata  in  which  it  is  dammed  back 
by  a  watertight  lining  (tubbing).  This  method  has  the  advantage 
of  requiring  no  plant  except  the  pipes,  but  there  is  the  disadvan- 
tage that  the  water  must  be  pumped  up  again,  unless  the  workings 
are  drained  by  an  adit  level.  However,  it  may  be  cheaper  and 
easier  to  work  the  ordinary  pumps  a  little  faster  than  to  erect 
special  air-compressing  machines.  Hydraulic  power  has  the  dis- 
advantage, compared  with  pneumatic  power,  of  not  ventilating  the 
workings  ;  and  in  certain  cases,  when  the  floor  is  soft  and  clayey, 
or  composed  of  rock-salt  or  saliferous  marls,  the  flow  of  water 
would  be  objectionable. 

The  petroleum  engine,  an  invention  of  modern  times,  is  already 
in  use  in  mines,  not  only  for  breaking  ground,  but  also  for 
pumping  and  hauling.  It  resembles  a  gas  engine,  save  that 
the  explosive  mixture  is  produced  by  heating  a  spray  of  petroleum 
and  air.  It  is  found  that  the  consumption  of  ordinary  mineral 
oil  is  decidedly  less  than  i  pint  per  brake  horse-power  per  hour  ; 
reckoning  the  oil  at  5^d.  per  gallon,  the  cost  of  a  brake  horse-power 
per  hour  is  less  than  ^d.  The  danger  which  these  machines  would 
introduce  into  some  mines  is  self-evident,  and  they  are  not  fitted  for 
use  in  breaking  ground  unless  the  workings  are  of  a  nature  to  allow 
them  to  be  moved  about  on  rails.  In  the  particular  case  of  the  thick 
bed  of  Cleveland  ironstone,  they  are  employed  with  advantage. 

TRANSMISSION  OF  POWER.—  The  generation  power 
in  the  working  place  itself  is  exceptional,  and  the  problem 
usually  to  be  solved  is  how  best  to  transmit  the  power  of  steam 
or  hydraulic  engines  at  the  surface  to  the  machines  employed 
underground. 

Power  is  transmitted  in  mines  in  six  different  ways  : 

(1)  By  rods.  (4)  By  air. 

(2)  By  ropes.  (5)  By  water. 

(3)  By  steam.  (6)  By  electricity. 

Rods  of  wood  or  iron  are  chiefly  employed  in  the  case  of  pump- 
ing machinery,  and  ropes  in  the  case  of  hauling  machinery,  both 
of  which  will  be  referred  to  in  later  chapters. 

Steam  generated  by  boilers  above  ground,  and  conveyed  by 
pipes  under  ground,  does  not  commend  itself  for  driving  machines 
at  the  working  faces  in  mines.  The  drawbacks  to  its  employment 
are  the  loss  of  pressure  through  condensation  in  the  pipes,  the 


UNI 


164  ORE  AND  STONE-MINING. 

inconvenience  and  danger  of  leaks,  the  discomfort  of  the  heat, 
and  the  trouble  of  the  exhaust  steam.  The  first  defect  may  be 
considerably  lessened  by  carefully  jacketing  the  pipes. 

There  remain,  then  :  air,  water,  and  electricity,  all  of  which  are 
in  actual  practical  use  at  the  present  time. 

Air. — The  transmission  of  power  by  compressed  air  has  the 
immense  advantage  that  the  exhaust  escaping  from  the  machines 
benefits  the  ventilation  of  the  mine ;  there  is,  on  the  other  hand, 
the  drawback  of  considerable  loss  of  power. 

Mr.  Sturgeon*  estimates  that  where  the  air  is  used  without 
re-heating  and  without  expansion,  the  engine  worked  by  the  air 
will  develop  only  31-9  per  cent,  of  the  power  of  the  engine 
used  in  compressing  it.  In  some  actual  cases  where  the  efficiency 
has  been  tested  practically,  the  loss  of  power  has  been  far 
greater  than  even  the  68" i  per  cent,  calculated  by  Mr.  Sturgeon. 
Professor  Kennedy  f  found  by  experiments  upon  the  transmission 
of  power  by  compressed  air  in  Paris  (Popp's  system),  that  the 
efficiency  with  cold  air  was  39  per  cent. ;  in  other  words,  it  re- 
quired 2 '6  indicated  horse-power  at  the  central  station  to  produce  i 
indicated  horse-power  at  the  motor. 

Air  compressors  are  simply  force-pumps,  but  the  ingenuity  of 
inventors  has  been  largely  exercised  in  order  to  overcome  the 
shortcomings  of  the  pneumatic  mode  of  transmitting  power. 
Attempts  have  been  made  especially  to  combat  the  loss  of 
efficiency  caused  by  the  clearance  spaces  and  by  the  heating  of 
air  when  compressed.  The  effects  of  these  two  drawbacks  are 
readily  understood.  Suppose  the  piston  of  an  air-compressing 
cylinder  to  have  reached  one  end  of  its  course,  the  air  in  the 
clearance  space  on  the  compressing  side  is  at  the  pressure  pro- 
duced by  the  machine ;  when  the  piston  reverses  its  stroke, 
this  air  expands,  and  the  admission  valves  will  not  open  .until  its 
pressure  has  been  reduced  to  a  point  just  below  that  of  the 
atmosphere.  The  first  part  of  the  stroke  is  therefore  ineffective, 
and  the  greater  the  clearance,  the  greater  is  the  difference  between 
the  theoretical  volume  of  air,  calculated  from  the  diameter  and 
stroke  of  the  piston,  and  that  actually  delivered  into  the  reservoir. 
However,  from  a  mechanical  point  of  view,  the  power  required  to 
compress  the  air  in  the  clearance  space  is  nearly  all  returned  by 
its  expansion  when  the  piston  changes  its  direction. 

The  loss  of  efficiency  due  to  heating  is  felt  in  two  ways :  the 
power  expended  in  producing  heat  is  wasted,  and  the  hotter  the 
air  the  smaller  is  the  actual  quantity  delivered  by  each  stroke 
of  the  compressor.  This  latter  evil  may  be  lessened  by  various 
methods  of  cooling,  and  we  are  thus  led  to  the  following  classifi- 
cation of  air-compressors  : 

*  "The  Birmingham  Compressed-air  Power  Scheme."     Paper  read  before 
the  British  Association.     Birmingham,  1886,  p.  15. 
f  Eep.  Brit.  Assoc.,  1889,  P-  45^. 


BREAKING  GROUND.  165 

I.  Water-column  compressors. 
II.  Injection  compressors. 
III.  Dry  compressors. 

I.  Water-column  Compressors. — The  machines  of  this  class  have 
the  advantage  of  using  a  cold  surface  for  compressing,  which 
absorbs  the  heat  of  the  air  with  which  it  is  in  contact.  They  also 
get  rid  of  the  drawback  of  clearance  or  dead  spaces,  for  the  water 
can  be  made  to  expel  all  the  air  at  each  stroke,  and,  lastly,  there 
can  be  no  escape  ofoair  past  the  piston.  An  early  form  was  that 
of  Sommeiller,*  and  Angstrom's  f  compressor,  used  with  success  in 
Sweden  in  the  infancy  of  rock-drills,  was  one  of  the  same  type. 
It  consisted  of  two  vertical  barrels,  connected  at  the  bottom,  and 
each  provided  at  the  top  with  an  inlet  and  an  outlet  valve.  The 
barrels  were  filled  with  water  in  such  a  manner  that  the  up  and 
down  motion  of  the  piston  forced  the  air  out  or  drew  it  in, 
according  as  the  column  was  being  made  to  rise  or  sink.  The 
piston  made  only  four  strokes  a  minute. 

Hanarte's  compressor  (Fig.  176),  now  employed  in  France  and 
Belgium,  has  a  piston  B  travelling  horizontally  like  that  of  Som- 

FIG.  176. 


meiller,  but  the  upright  portions  A  A,  instead  of  being  cylinders, 
are  paraboloids  ;  C  C  are  the  inlet  valves,  and  D  is  one  of  the 
outlet  valves.  This  arrangement  allows  a  greater  number  of 
strokes  per  minute,  because  the  speed  of  the  water  diminishes 
as  it  rises,  although  the  speed  of  the  piston  may  be  uniform,  and 
also  because  the  area  of  the  cooling  surface  increases  in  proportion 
to  the  amount  of  heating  generated  by  compression.  A  Hanarte 
compressor  erected  at  BlanzyJ  in  1887  could  not  be  driven  at 
more  than  24  strokes  a  minute,  and  gave  some  trouble  from 
frequent  repairs  of  the  valves.  Like  other  machines  of  this  class, 
it  also  had  the  defect  of  dashing  a  little  water  through  the  valves, 
but  on  the  whole  it  worked  satisfactorily. 

*  Figured  in  Hughes'  Text-Book  of  Coal  Mining,  p.  49. 

t  C.  Le  Neve  Foster,  "An  Account  of  Bergstrom's  Boring  Machine,  now 
in  use  at  the  Persberg  Mines,  Sweden,"  Trans.  Min.  Assoc.  Cornwall  and 
Devon,  1867,  p.  7. 

+  Mathet,  L'air  comprim£  aux  mines  de  Blanzy.  Saint-Etienne,  1889, 
pp.  15,  24. 


1 66 


ORE  AND  STONE-MINING. 


II.  Injection  Compressors. — In  the  injection  compressors,  water 
is  being  constantly  introduced  in  order  to  absorb  heat  from  the 
air,  and  at  the  same  time  it  has  the  effect  of  partly  or  completely 
tilling  up  the  clearance  spaces,  and  of  so  still  further  contributing 
to  the  effective  working  of  the  machine.  It  is  either  drawn  in 
through  the  admission  valves,  or,  better,  it  is  forced  in  as  a  spray. 
In  a  finely  divided  state  it  will  naturally  act  more  efficaciously  in 
a  short  time,  which  is  of  the  utmost  importance  with  a  quick- 
working  compressor. 

Figure  177  represents  one  form  of  a  Dubois  and  Frangois 
injection  compressor.  A  is  the  piston,  B  B  are  the  two  inlet 

FIG.  177. 


valves,  and  C  C  the  two  outlet  valves.  D  D  are  pipes  bringing  in 
water,  which  is  injected  as  a  spray  into  the  cylinder. 

It  has  been  found  in  many  cases  that,  though  the  spray 
undoubtedly  has  a  cooling  effect,  its  use  is  coupled  with  the  dis- 
advantage that  the  piston  and  cylinder  wear  rapidly ;  therefore 
many  engineers  are  of  the  opinion  that  it  is  better  to  put  up  with 
a  slight  imperfection  in  the  cooling,  than  to  have  a  loss  of 
efficiency  through  a  badly  fitting  piston. 

III.  Dry  Compressors. — Very  many  compressors  are  worked 
dry,  and  the  air  is  cooled  by  its  contact  with  the  surface  of  the 
sides  or  ends  of  the  cylinder,  which  are  prevented  from  getting 
hot  by  the  circulation  of  cold  water  outside  them. 

Among  the  dry  compressors  may  be  mentioned  that  of  Burck- 
hardt  and  Weiss,  of  Bale,  which  was  in  favour  at  Blanzy*  in  1889, 
on  account  of  certain  advantages  which  it  possesses  over  other 
forms  of  machines,  especially  the  great  speed  at  which  it  can  be 
worked,  the  delivery  of  a  dry  air,  and  the  suppression  of  the  evil 
caused  by  clearance.  The  benefit  of  a  rapid  stroke  is  that  a  small 
machine,  costing  less  money,  occupying  less  space,  more  easily 

*  Mathet,  op.  cit.  p.  24.  Further  details  concerning  this  compressor 
will  be  found  in  a  pamphlet  issued  by  the  firm  for  the  Paris  Exhibition, 
1889,  and  in  the  Revue  Universelle  cles  Mines  et  de  la  Metallurgy ,  1889, 
p.  279  ;  1890,  p.  202. 


BREAKING  GROUND. 


167 


transported,  and  more  cheaply  erected,  does  as  much  work  as  a 
large  machine  driven  slowly.  Great  speed  of  working  is  rendered 
possible  by  effecting  the  distribution  of  the  air  by  a  slide-valve 
worked  mechanically,  instead  of  having  valves  which  open  and  shut 
automatically,  owing  to  the  difference  of  pressure  on  their  faces ; 
and  the  injurious  effect  of  clearance  is  greatly  reduced  by  having 
a  small  passage  in  the  slide-valve,  which  puts  both  sides  of  the 
piston  into  communication  with  each  other  at  the  end  of  every 
stroke.  Consequently,  when  the  direction  of  the  piston  is  reversed, 
it  at  once  begins  to  draw  in  air,  instead  of  having  the  first  part  of 
its  course  ineffective,  as  is  the  case  with  many  compressors.  It 
must  be  pointed  out,  however,  that  the  increase  in  the  volumetric 
delivery  of  air  effected  in  this  manner  is  carried  out  at  the  expense 
of  a  certain  amount  of  power.  As  already  explained,  the  power 
required  for  compressing  the  air  in  the  clearance  space  is  not 
entirely  thrown  away  in  the  ordinary  machines  ;  a  part,  at  all 
events,  is  stored  up  for  a  moment,  and  helps  the  piston  in  its 
course  as  soon  as  the  stroke  is  reversed.  In  the  Burckhardt  and 
Weiss  compressor  this  power  is  wasted.  The  cooling  arrangements 
of  this  machine  have  been  very  carefully  studied.  A  current  of 
cold  water  is  made  to  circulate  not  only  around  the  cylinder  as 
usual,  but  also  at  both  ends,  a  matter  of  importance,  because  it  is 
precisely  at  the  ends  that  the  heating  is  greatest,  and  that  there 
is  the  greatest  need  of  refrigeration.  The  piston  and  the  slide- 
valve  are  kept  greased  with  oil  delivered  drop  by  drop  from  one  of 
Weiss's  sight-feed  lubricators. 


The  long  experience  of  the  Ingersoll-Sergeant  Rock  Drill 
Company  *  has  led  them  to  adopt  the  compressor  shown  in  Fig. 
178.  It  has  a  double-acting  air  cylinder,  with  an  inlet  valve  a  on 
each  face  of  the  piston.  Fig.  179  is  a  perspective  view  of  one  of 

*  Saunders,  Compressed  Air  Production.     New  York,  1891,  p.  '22. 


i68 


ORE  AND  STONE-MINING. 


FIG.  179. 


these  ring-shaped  valves.  The  compressed  air  leaves  the  cylinder 
by  the  valves  b  b  (Fig.  178) ;  c  c  are  grooves  turned  in  the  ends 
of  the  cylinder  which  receive  the  projecting  parts  of  the  valves  on 
the  piston,  and  so  enable  the  clearance  to  be  reduced  to  a  minimum. 
The  cylinder  is  kept  cool  by  the  circulation 
of  water  through  the  spaces  d  and  e,  and, 
save  where  there  is  the  outlet  valve,  the 
whole  of  each  end  participates  in  the  re- 
frigeration by  means  of  the  water-jackets, 
d  d.  The  action  of  the  compressor  is  simple. 
The  air  enters  the  piston  by  the  tail  pipe 
which  is  attached  to  it,  and,  according  to  the 
direction  of  the  stroke,  opens  one  or  other  of 
the  ring-valves  leading  into  the  cylinder.  When  the  direction  of 
the  stroke  is  reversed,  this  air  is  compressed,  opens  one  of  the 
valves,  b,  and  passes  out  at/. 

For  very  high  pressures  it  may  be  advisable  to  use  compound 
machines ;  that  is  to  say,  machines  in  which  the  compression  is 
effected  in  two  cylinders  instead  of  one.  The  air  is  first  partly 
compressed  in  a  large  cylinder,  and,  passing  into  a  smaller  one,  is 
brought  to  the  required  high  pressure.  For  the  pressures  ordinarily 
used  in  mining,  say  50  to  70  Ibs.  per  square  inch,  compound  com- 
pressors are  not,  as  a  rule,  thought  necessary. 

The  usual  type  of  air  compressor  used  at  mines  is  illustrated  by 
the  diagram,  Fig.  180.  A  A  are  the  two  steam  cylinders,  B  the 
fly-wheel,  and  C  C  the  two  air  cylinders.  It  is  sometimes  thought 

FIG.  1 80. 


HUM 


'iinniHiniiiiiiii 


more  economical  to  make  the  engine  compound,  and  in  that  case 
one  of  the  two  cylinders  takes  the  steam  at  high  pressure  and  the 
other  at  low  pressure,  after  it  has  somewhat  expanded. 

A  point  often  neglected  is  the  state  of  the  air  supplied  to  the 
compressor.  The  Ingersoll-Sergeant  Company  are  quite  right  in 
insisting  that  the  air  should  be  taken  where  it  is  as  dry,  cold,  and 
free  from  dust  as  possible. 

In  order  to  secure  uniformity  of  pressure  and  get  rid  of  water 
and  impurities,  the  air  is  led  from  the  compressor  into  a  reservoir, 
often  an  egg-ended  boiler  ;  it  should  be  provided  with  a  safety- 
valve,  a  pressure  gauge,  and  also  with  a  cock  for  letting  off  the 


BREAKING  GROUND. 


169 


water  which  collects  gradually,  especially  in  the  case  of  wet  com- 
pressors. Sometimes  a  gauge  is  added  in  order  to  indicate  the 
height  to  which  the  water  rises. 

Several  underground  reservoirs  have  been  constructed  at  Mans- 
feld.*  One  is  a  chamber  10  m.  long,  1*5  m.  wide,  and  1-5  m.  high 
at  the  mouth,  and  then  enlarged  to  3  m.  wide  by  2*2  m.  high. 
All  loose  stone  was  carefully  removed,  and  the  walls  were  plastered 
over,  first  with  cement,  and  then  with  a  mortar  made  of  equal 
parts  of  cement  and  sand.  A  brick  dam  was  erected  in  the  con- 
tracted mouth  of  the  bottle-like  chamber,  and  in  order  to  make  it 
thoroughly  air-tight,  a  space  2  inches  wide  was  left  in  the  middle, 
and  filled  up  with  cement. 

The  dam  is  provided  with  a  drain-pipe,  a  (Fig.  181),  just  above 
the  floor,  and  a  manhole  pipe,  6,  20  inches  (o'5  m.)  in  diameter 
clear ;  d  and  e  are  two  of  the  four  pipes  taking  the  compressed 

FIG.  181. 


FLOOR 


SCALE 


MtTRES 


1  1  1  1  1  1  1  1  1  1  ' 

I 

1 

1 

i^ 

1 

; 

Ml 

O'S 

i 

0 

i 

I 

2. 

3 

4 

5 

6 

FE.ET 

Fr.o 

C 

4- 

6 

8           »0 

IB 

14 

16 

18 

£0 

air  into  the  workings, 
manhole  cover  carries 


Each  pipe  has  a  strong  cock,  and  the 
a  pressure-gauge.  The  drain-pipe  a  is 
opened  at  least  once  a  day,  to  blow  off  the  dirty  water  which  accu- 
mulates. 

The  underground  reservoirs  have  several  advantages.  In  the 
first  place  they  cost  only  one-third  of  what  they  would  have  done 
if  constructed  of  sheet-iron  ;  secondly,  they  serve  as  accumulators, 
and  by  storing  up  power  make  the  machines  far  more  independent 
of  the  compressors.  Even  if  the  compressor  stops  for  a  time,  the 
underground  machinery  can  go  on  working  ;  besides,  when  the 
reservoir  is  at  the  surface,  the  machines  nearest  to  it  get  a  better 

*  Schrader,  "Die  neueren  Fortschritte  bei  der  Anwendung  vonGesteins- 
Bohrmaschinen  und  die  Versuche  mit  kleinen  Schrammaschinen  beim 
Ma  nsf  elder  Kupferschieferbergbau,"  Zcitschr.f.  B.-  H.-u.  S.-  Wesen,  vol  xli., 
1893,  p.  119. 


OF  THE 

TTTTTVP.  T? 


F70 


ORE  AND  STONE-MINING. 


supply  than  those  at  a  distance.  A  third  advantage  is  the  puri- 
fication of  the  air,  which  deposits  moisture,  particles  of  dust,  and 
lubricants.  Lastly,  an  underground  reservoir  cannot  explode. 

The  compressed  air  of  a  surface  reservoir  is  conveyed  into  the 
mine  by  mains.     They  are  often  made  of  cast-iron  with   flange 


FIG.  182. 


FIGS.  183  &  i! 


joints  of  some  kind.  Fig.  182  gives  the  joint  used  by  Mathet  at 
Blanzy  for  the  pipes  going  down  the  shaft,  which  are  4^  inches 
(120  mm.)  in  diameter  inside.  The  joint  is  made  air-tight  by  an 
india-rubber  washer,  placed  in  the  groove  shown  in  the  upper 
flange,  which  is  squeezed  tight  when  the  two  flanges  are  drawn 
together  by  five  bolts.  The  manner  in  which  the  pipe  is  sup- 
ported in  the  shaft  is  rendered  plain  by  Figs.  183  and  184  (the 
dimensions  are  in  millimetres).  Cross-beams  are  put  in  at  intervals 
of  about  100  yards,  and  the  pipe  is  further  kept  in  place  by  iron 
clamps  driven  into  the  brick  lining  of  the  pit  every  20  yards. 


BREAKING  GROUND.  171 

Messrs.  Eadie  &  Sons  have  several  joints  for  lap-welded  wrought- 
iron  and  steel  pipes  used  in  conveying  air,  steam  and  water,  among 
which  may  be  specially  mentioned  the  one  represented  in  Fig.  185. 
In  this  case  each  end  of  the  tube  is  turned  up  so  as  to  form  a 
small  flange,  after  a  loose  ring  has  been  slipped  on.  The  loose 
rings  are  made  with  spigot  and  faucet,  which  can  be  drawn 
together  by  four  bolts,  and  thus  made  to  squeeze  an  india-rubber 
washer  placed  between  the  two  pipes.  Joints  of  this  description 
are  very  easily  and  quickly  made,  and  are  found  to  remain  staunch; 
they,  therefore,  commend  themselves  to  the  miner.  The 
lap- welded  wrought- iron  and  steel  tubes  have  the  advantage  of 
lightness  and  cheapness,  and  as  they  are  tested  to  at  least  700 
Ibs.  per  square  inch  they  are  fully  strong  enough  to  stand  far 
greater  pressures  than  are  met  with  in  the  air-mains  of  mines. 
In  America  the  line  of  welding  is  sometimes  spiral  instead  of 
longitudinal ;  and  in  this  country  Rylands'  glass-lined  iron  pipe, 
3  inches  in  diameter  internally,  has  been  chosen  in  one  case  for 
the  sake  of  lessening  the  friction. 

The  air- compressors  furnishing  supplies  to  the  Chapin  Mine, 
Michigan,  are  situated  at  a  distance  of  three  miles  from  the  work- 
ings, in  order  to  take  advantage  of  the  Quinnesec  Falls  as  a  source 
of  power.  The  main  leading  from  the  compressors  is  a  riveted 
pipe  made  of  J-inch  wrought-iron,  24  inches  in  diameter,  in  lengths 
of  48  feet,  and  having  expansion  joints  every  ten  lengths. 

For  branches  conveying  air  from  the  mains  to  the  actual  work- 
ing places,  gas-pipe  with  screwed  sockets  is  largely  employed, 
finally,  when  the  machine  has  to  be  shifted  continually,  there  is 
a  piece  of  india-rubber  hose,  which  should  be  covered  in  some 
way,  so  as  to  prevent  its  being  unnecessarily  worn  when  being 
dragged  about  over  rough  surfaces.  Wire  wound  round  the  hose 
frdds  greatly  to  its  durability.  Flexible  metallic  tubing  has  been, 
Jised  with  success  in  the  place  of  india-rubber  hose. 

Water. — Force-pumps  at  the  surface  are  made  to  drive  water 
through  pipes  to  places  underground  where  hydraulic  engines  are 
worked  by  its  pressure.  They  may  be  aided  by  an  accumulator  } 
that  is  to  say,  a  cylinder  into  which  the  water  is  forced  so  as  to 
jift  a  plunger  supporting  a  heavy  weight,  The  accumulator 
serves  to  regulate  the  load  upon  the  engine  working  the  force- 
pump,  and  to  store  up  power  while  the  mining  machinery  happens 
to  be  idle.  It  acts,  in  fact,  like  the  reservoir  used  with  an  air- 
compressor.  A  second  method  of  utilising  power  at  the  surface 
consists  in  drawing  off  water  in  pipes  from  the  rising  main  'of  the 
pumps.  In  both  these  cases  any  natural  fall  of  the  water  adds  its 
effect  to  that  produced  by  the  engine  above  ground. 

Hydraulic  power  has  the  great  convenience,  therefore,  that  it  is 
sometimes  obtainable  without  any  extra  plant  being  required. 
The  water,  after  having  done  its  work,  runs  out  naturally  if  the 
workings  are  above  an  adit,  but  has  to  be  pumped  up  if  they  are 


172 


OEE  AND  STONE-MINING. 


below  it.  However,  it  may  be  cheaper  and  easier  to  work  the 
pump  a  little  faster  than  to  erect  special  air-compressing  plant. 
Hydraulic  power  has  the  disadvantage,  compared  with  pneumatic 
power,  of  not  ventilating  the  workings,  and,  as  already  pointed 
out,  of  being  objectionable  with  certain  rocks. 

Electricity. — This  method  consists  in  driving  a  dynamo  by  any 
available  power  at  the  surface,  and  then  conducting  the  current 
by  wires  to  an  electric  motor  underground.  The  possibility  of 
conveying  power  by  wires  is  an  immense  convenience  to  the  miner. 
The  advantages,  compared  with  transmission  by  air  or  water,  are 
that  it  is  much  easier  to  fix  wires  than  pipes  ;  wires  occupy  much 
less  room,  and  do  not  suffer  like  pipes  from  movements  of  the 
rocks  due  to  the  workings.  Like  water,  but  unlike  compressed 
air,  electricity  does  not  assist  in  ventilating  the  working  place, 
and  in  fiery  mines  there  may  be  danger  from  sparks. 

Messrs.  L.  &  C.  Atkinson,  in  speaking  of  electric  transmission,, 
in  a  very  useful  paper,*  lately  read  before  the  Institute  of  Civil 
Engineers,  say  :  "  It  will  be  seen  that  an  efficiency  of  67  per  cent, 
can  readily  be  obtained  even  when  transmitting  nearly  100  h.-p. 
to  a  distance  of  more  than  two  miles,  and  without  any  attempt 
being  made  to  get  specially  good  results,  the  whole  plant  being 
such  as  can  be  worked  by  unskilled  men." 

The  following  table  has  been  prepared  by  Messrs.  Atkinson  to 
show  the  relative  cost  of  transmitting  power  by  compressed  air 
and  by  electricity  : 


"5  g 

V. 

O 

S3 

t 

|e| 

3 

£ 

0  3 
O 

System. 

W  8 

«  a 

c«  3 

PH"  ,; 

»'l 

i* 

l|? 

ze  of  cable 
pipe. 

l! 

ce  of  cable 
pipe. 

ice  of  mot 

*>6 

•all 

Efficiency. 

03  '/2 

03 

|*ti 

« 

OH 

£ 

£ 

fe" 

£ 

^ 

^ 

^ 

Electric    . 

I5-4 

IO    !    2OOO 

A  in- 

2IO 

I92 

95 

497 

65% 

Compressed  air 

33'3 

10 

2000 

4  ins. 

130 

700 

63 

893 

30% 

Compared  with  compressed  air,  the  plant  is  less  expensive,  and 
there  is  the  immense  advantage  of  a  smaller  loss  of  power  in 
transmission. t  According  to  experiments  made  with  the  electric 
plant  at  St.  John's  Colliery,  Normanton,  and  Llanerch  Colliery, 
Monmouthshire,  the  efficiency  of  the  plant — i.e.,  the  ratio  between 

*  Proc.  Inst.  Civ.  JEng.,  vol.  civ.     Session  1890-91,  p.  89. 

t  Snell,  "Electrical  Transmission  of  Power  in  Mining  Operations."' 
Paper  read  before  the  Lancashire  Branch  of  the  National  Association  of 
Colliery  Managers,  Wigan,  September  28,  1889. 


BREAKING  GROUND.  173 

the  work  done  in  pumping  and  hauling  by  the  electric  motor, 
and  the  work  given  out  by  the  steam  engine  at  the  surface — is 
as  much  as  from  43  to  48  % . 

Making  every  allowance  for  the  fact  that  these  figures  are 
given  by  avowed  advocates  of  electricity,  it  undoubtedly  seems  that 
compressed  air  is  at  a  disadvantage  as  regards  cost  and  efficiency 
when  compared  with  its  youngest  rival. 

A  combination  of  electricity  and  compressed  air  has  been 
found  advisable  in  some  cases.  The  power  is  transmitted  under- 
ground by  electricity  to  motors  which  drive  small  air-compressors 
placed  in  the  vicinity  of  the  working  places  where  percussive 
drills  are  required. 

Hitherto  the  principal  applications  of  electrical  transmitting 
plant  have  been  for  pumping,  winding,  and  hauling,  and  little 
has  been  done  in  the  way  of  machines  for  breaking  ground ;  but 
rotary  and  percussive  drills  driven  by  electricity  are  already 
beginning  to  be  employed. 

EXCAVATING  MACHINERY.— The  machines  used  for 
excavating  may  be  classified  as  follows  : 

(1)  Diggers. 

(2)  Dredges. 

(3)  Drills  for  boring  holes  for  blasting  or  wedging. 

(4)  Machines  for  cutting  grooves. 

(5)  Machines  for  excavating  complete  tunnels. 

I.  Steam  Digger. — The  steam  navvy,  though  specially  the 
machine  of  the  railway  or  canal  engineer,  must  not  be  forgotten 
by  the  miner,  who  has  to  excavate  large  quantities  of  com- 
paratively soft  deposits  near  the  surface,  or  to  remove  overburden 
such  as  sand,  gravel,  stiff  clay,  or  chalk.  After  a  preliminary 
shattering  by  blasting,  even  hard  rock  may  be  shovelled  up  by 
these  machines. 

Among  them  we  may  mention  Dunbar  &  Rmtoris  Steam  Navvy  * 
(Fig.  1 86),  largely  used  in  making  the  Manchester  Ship  Canal.  It 
is  a  steam  crane  which  brings  a  bucket,  armed  with  teeth  and  a 
sharp  edge,  against  the  side  of  the  excavation,  draws  it  up  and 
drops  its  contents  into  a  railway  waggon.  The  figure  needs  but 
little  explanation.  A  is  the  vertical  boiler  giving  steam  to  two 
cylinders,  one  of  which  is  shown  at  B.  These  &re  made  to  work 
drums  for  raising  and  lowering  the  bucket  C,  by  the  chain  D, 
or  for  turning  the  jib  G. 

In  order  to  work  the  navvy  the  bucket  is  lowered  till  the 
handle  E  is  vertical ;  it  is  then  brought  against  the  bottom  of 
the  working  face,  and  drawn  up  by  the  chain  D;  the  teeth 
enter  the  earth  and  open  the  way  for  the  cutting  edge.  The 
bucket  fills  itself,  is  swung  over  the  waggon  by  the  jib,  and 

*  Mining  Journal,  vol.  Iviii.  (1888),  p.  1242. 


I74 


ORE  AND  STONE-MINING. 


emptied  by  pulling  tlie  cord  H.  It  closes  automatically  when 
lowered. 

The  depth  of  the  cut  depends  upon  the  length  of  the  radius  given 
to  the  circular  arc  described  by  the  cutting  tool.  The  radius, 
-and  therefore  the  cut,  can  be  altered  by  a  man,  standing  at  the 
foot  of  the  jib-post,  who  works  the  chain  F ;  this  actuates  a 
pinion  gearing  into  a  rack  upon  the  bucket  handle  E. 

The  navvy  requires  three  men,  one  attending  to  the  raising 
and  lowering  of  the  bucket  and  swinging  of  the  jib  ;  a  second 
regulating  the  depth  of  the  cut  and  the  discharge,  and  lastly  a 

FIG.  1 86. 


fireman.  Each  bucket  contains  i  to  ij  cubic  yards,  and 
three  buckets  will  fill  a  contractor's  waggon.  In  ten  hours  this 
machine  will  excavate  and  load  from  700  to  1000  cubic  yards  of 
earth. 

When  all  the  earth  within  reach  has  been  excavated,  the  jack 
screws  are  loosened  and  the  machine  made  to  propel  itself  forward 
on  the  rails  a  few  feet. 

A  somewhat  similar  machine  is  Wilson's  Steam  Crane  Excavator. 
It  is  a  10  ton  steam  crane  to  which  a  digging  bucket  can 
speedily  be  attached.  The  machine  can  therefore  be  used  as  a 
crane  or  as  a  digger,  as  occasion  requires. 

This  is  also  possible  with  the  Wkittaker  Excavator,  which,  like 
the  two  previous  steam  navvies,  has  been  used  for  making  the 
Manchester  Ship  Canal. 

Steam  diggers  are  much  used  by  miners  and  quarriers  in  the 
United  States,  and  especially  the  machines  made  by  the  Marion 
and  the  Bucyrus  Steam  Shovel  Companies,  which  in  principle 
resemble  the  Dunbar  and  Huston  Navvy.  The  Earnhardt  Steam 
Shovel  of  the  former  company  is  employed  in  the  Mesabi  Range, 


BREAKING  GROUND.  175 

Minn.,  and  in  other  places,  for  stripping  off  overburden  and  for 
excavating  iron  ore,  and  the  Bucyrus  Company  applies  its  digger 
with  success  to  auriferous  gravel,  instead  of  washing  it  down  by 
the  hydraulic  process. 

Besides  serving  as  true  excavating  machines,  these  steam 
shovels  are  found  economical  for  loading  ore  from  stock  piles  into 
railway  waggons. 

Another  kind  of  digger  may  be  spoken  of  as  a  dry  dredye  ;  a 
machine  of  this  class,  made  by  a  Liibeck  Company,*  is  in  use, 
among  other  places,  at  a  large  openwork  where  brown  coal  is 
being  worked  near  Briihl,  between  Bonn  and  Cologne.  The 
excavating  part  of  this  steam  digger  consists  of  a  long  arm  with 
a  chain  of  buckets,  like  those  of  a  dredge,  which  are  brought 
successively  against  the  face  of  the  overburden  and  then  carry  the 
gravel  into  a  hopper ;  side-tipping  waggons  are  run  under  this 
hopper  and  quickly  filled  by  opening  a  door. 

The  pulley  which  makes  the  endless  belt  of  buckets  revolve  is 
set  in  motion  by  friction  gear,  so  that  there  is  no  fear  of  a  break- 
age, even  when  a  bucket  comes  against  some  very  hard  place  in 
the  overburden  which  it  cannot  penetrate.  The  arm  carrying  the 
buckets  can  be  raised  and  lowered  as  required. 

Theoretically  this  machine  will  excavate  1000  cubic  metres 
(1300  cubic  yards)  in  ten  hours;  the  actual  work  is  stated  to  be 
about  700  cubic  metres  (915  cubic  yards)  in  that  time. 

The  Bucyrus  Steam  Shovel  Company  likewise  makes  a  machine 
of  this  type. 

II.  Dredges. — The  beds  of  rivers  and  lagoons,  and  even  sea 
beaches  and  bottoms,  sometimes  contain  minerals  which  can  be 
excavated  by  dredges  like  those  used  for  improving  harbours. 
There  are  three  types  : — 

(1)  Bucket  dredges. 

(2)  Grab  dredges. 

(3)  Suction  dredges. 

i.  Bucket  Dredges. — Kincaid  &  McQueen's  machine  (Fig.  187), 
used  with  success  upon  the  Molyneux  river,f  New  Zealand,  is  a 
big  barge,  66  feet  long,  with  an  endless  chain  of  buckets  and  a 
pontoon  on  each  side.  The  total  width  of  the  barge  and  two 
pontoons  is  26  feet. 

The  buckets  are  worked  by  a  steam-engine  upon  the  barge, 
which  also  drives  a  cylindrical  screen  for  separating  any  large 
stones.  The  engine  is  a  vertical  inverted  compound  steam-engine, 
with  cylinders  of  1 2  inches  and  2  2  inches  diameter  respectively, 
and  1 8  inches  stroke,  working  at  a  pressure  of  60  Ibs.  per  square 
inch. 

*  "  Liibecker  Maschinenbau  Gesellschaft."  * 

•   f  Mines   Statement.     By  the   Minister  of  Mines,   the   Hon.   W.   J.   M. 
Larnach,  C.M.G.     Delivered  July  6,  1886,  p.  17. 


i76 


ORE  AND  STONE-MINING. 


The  buckets  can  be  made  to  raise  as  much  as  150  tons  of  stuff 
per  hour,  and  to  excavate  to  a  depth  of  25  feet  below  the  level  of 
the  water.  A  steam  winch  serves  for  raising  and  lowering  each 

FIG.  187. 


•of  the  dredging  ladders,  or  frames,  carrying  the  endless  chains  of 
buckets,  and  also  for  working  the  mooring  chains. 

A  dredge  of  a  similar  kind  has  been  used  on  the  river  Oreo,  in 
Piedmont,*  for  the  purpose  of  excavating  an  auriferous  alluvium 
in  order  to  extract  gold  from  it,  and  with  the  further  object  of 
preventing  floods  by  straightening  the  course  of  the  river  and 
embanking  it. 

The  dredge  has  an  engine  of  50  h.-p.,  and  is  said  to  be  capable 
of  raising  3200  cubic  yards  of  alluvium  (2500  cubic  metres)  in  22 
hours.  It  can  excavate  to  a  depth  of  26  feet  (8  m.). 

2.  A  yrab  dredge  consists  of  a  single  hemispherical  or  semi- 
cylindrical  vessel,  which  is  made  so  that  it  opens  when  lowered, 
fills  itself  on  touching  the  earth  and  closes  as  soon  as  it  is  raised. 
The  raising  and  lowering  are  done  by  a  crane.  The  semi-cylindrical 
bucket  may  be  armed  with  teeth ;  it  descends  with  the  teeth  open 
and  is  drawn  up  with  them  closed. 

Bruce  &  Batho  make  some  of  their  grabs  with  three  or  four 
sharp  blades,  like  very  pointed  spades,  which  close  upon  being 
lifted,  and  form  a  hemispherical  bucket.  A  somewhat  similar 
grab  dredge  has  been  employed  for  stripping  off  the  overburden 
from  a  bed  of  auriferous  gravel  in  Calif ornia.f 

The  Priestman  Grab  dredger  has  been  used  for  excavating  the 

*  Gazzettadi  Torino.     May  u,  1886. 

t  Eighth  Annual  Report  of  ilie  State  Mineralogist,  for  the  year  1888. 
.Sacramento,  1888,  p.  100. 


BREAKING  GROUND. 


177 


auriferous  gravel  of  the  river  Nechi  and  its  tributaries  in  the 
United  States  of  Colombia  (Fig.  188),  and  it  likewise  serves  as 
a  digging  machine  on  land,  and  even  for  sinking  shafts. 


FIG.  1 88. 


3.  The  Suction  dredge  may  be  described  very  shortly  as  a  cen- 
trifugal pump  arranged  to  draw  up  sand  and  gravel  with  the 
water.  It  is  placed  upon  a  barge,  and  the  suction  pipe  can 
be  lowered,  raised,  or  moved  from  one  side  to  the  other,  so  as 
to  attack  any  part  of  the  sea  or  river-bottom.  A  Welman 
dredge  of  this  type,*  used  for  excavating  the  ocean  beach  at  the 
mouth  of  the  Waipapa  Creek,  has  suction  and  delivery  pipes  12 
inches  in  diameter.  It  appears  to  be  doing  excellent  work  where 
the  bulk  of  the  material  to  be  treated  consists  of  sand  and  fine 
shingle.  The  beach  is  reckoned  to  yield  about  3  grains  of  gold 
per  ton,  whilst  the  working  expenses  are  only  2  grains  per  ton. 

III.  Rock  Drills. — Most  of  the  machine  drills  have  a  per- 
cussive action,  but  a  few  are  rotary ;  for  Stapff  pointed  out  some 
years  ago  that  if  a  rock  may  be  chipped  off  by  power  communi- 
cated by  a  blow,  it  may  also  be  chipped  off  by  a  similar  amount 
of  power  communicated  by  pressure. 

i.  Rotary  Drills. — Following  the  order  I  have  adopted  in 

*  J\tr/itni/t  1/ttii-t/  /,'<  f,/>rlH  on  the  Min'nuj  Industry  of  New  Zealand.  Wel- 
lington, 1890,  p.  87  ;  and  1891,  p.  75. 


i78 


OKE  AND  STONE-MINING. 


the  case  of  the  hand  tools,  I  will  first  speak  of  the  rotary 
machines. 

Brandt's  rotary  drill  consists  of  a  hollow  borer  which  has  a 
steel  crown,  with  cutting  edges,  screwed  on.  The  tool  is  kept 
tight  against  the  rock  by  the  pressure  of  a  column  of  water,  and 
is  at  the  same  time  made  to  rotate  by  two  Jittle  water-pressure 
engines,  whilst  a  stream  of  water  passing  down  through  the 
borer  washes  away  the  chips  and  sand,  and  keeps  the  cutting 
edges  cool.  In  principle,  therefore,  this  drill  resembles  the 
original  diamond  boring  machine  of  De  la  Roche  Tolay  and 
Perret,  save  that  the  crown  is  made  of  steel  and  not  of  diamonds. 
It  has  been  used  with  success  in  railway  tunnels  and  mines. 

Brandt's  machine  was  worked  at  one  of  the  mines  at  Freiberg* 
in  Saxony,  with  water  at  a  pressure  of  83*5  atmospheres,  of  which 
56*6  atmospheres  were  obtained  by  pressure  pumps  provided  with 
an  accumulator,  and  26*9  atmospheres  by  natural  fall,  owing  to 
the  level  in  which  the  machine  was  used  being  277  metres  below 
the  pump.  The  water  was  conveyed  to  the  pump  in  iron  pipes 
ij-  inches  in  diameter  inside.  The  diameter  of  the  holes 
was  2 1  inches,  and  they  could  be  bored  in  gneiss  at  the  rate  of 
i  J  inches  per  minute.  The  stretcher  bar  on  which  the  machine 
is  carried  is  hollow,  and  has  a  piston  which  can  be  forced  out  by 
hydraulic  pressure  so  as  to  fix  it  firmly.  A  similar  bar  is  some- 
times used  with  percussive  drills.f 

Comparative  experiments  were  made  at  Freiberg  between  this 
drill,  hand-labour,  and  a  percussion  drill,  and  the  results  given 
below  are  of  much  interest  and  importance.  In  the  case  of  the 
two  machine  drills,  the  cost  includes  interest  on  and  depreciation  of 
plant,  repairs,  and  the  estimated  expense  of  providing  steam 
power,  which  would  have  been  necessary  if  water  power  had  not 
been  available : — 


Hand  boring. 

Schram's 
drill. 

Brandt's 
drill. 

Distance     driven    per    week     in 

metres         ..... 

°'95 

4  '5 

5'° 

Cost  in  marks  per  metre  driven 
Wages   realised  by  the  miners  in 

120-134 

77-4-85-25 

74-34 

marks,  per  eight-hours  shift        , 

1-85-2-05 

3-48-3-66 

376 

The  benefits  of  machine  work  are  very  marked  indeed,  both  as 
regards  rate  and  cost  of  driving,  and  wages  earned  by  the  men. 

Brandt's  rotary  drill  did  its  work  cheaper  and  faster  than 
Schram's  machine ;  but  nothing  is  said  in  the  original  notice  of 

*  JaJirbuch  fur  das  Berg-  und  Huttenwesen  im  Konigreiche  Saclisen  auf 
das  Jahr  1882,  p.  18. 

t  Ann.  Mines.     Ser.  8,  vol.  ii.  1882,  PI.  I.,  Fig.  6. 


BREAKING  GROUND.  179 

the  advantage  of  a  machine  driven  by  compressed  air  for  venti- 
lating workings,  such  as  advanced  headings  in  which  these  drills 
are  employed. 

In  Jarolwiotis*  drill  the  borer  is  likewise  a  rotating  tube 
armed  with  steel  teeth,  but  it  is  fed  towards  and  pressed  against 
the  rock  by  a  differential  screw  arrangement.  Water  passing 
through  the  hollow  borer  keeps  the  teeth  cool  and  carries  away 
the  debris.  The  machine  can  be  worked  by  hand,  but  a  little 
water-pressure  or  compressed-air  engine,  or  an  electric  motor  will 
be  preferable. 

Experiments  have  been  made  lately  at  Zauckerode,t  in  Saxony, 
with  a  diamond  drill  for  boring  holes  for  blasting. 

The  machine  is  a  steel  tube  with  a  steel  crown  screwed  on,  con- 
taining four  black  diamonds ;  it  is  driven  by  a  small  electric  motor 
upon  a  carriage  on  wheels  in  the  level,  by  means  of  a  shaft  with 
two  universal  joints.  This  arrangement  allows  holes  to  be  bored 
in  any  direction  required  for  driving  the  tunnel.  The  holes  are 
from  IT  inch  to  1*3  inches  (28  to  34  mm.)  in  diameter. 

The  result  of  the  experiments  is  that  in  hard  clay-slate  with 
numerous  veins  of  quartz,  or  in  gneiss,  granite,  or  rocks  of  similar 

FIG.  189. 


hardness,  a  level  can  be  driven  nearly  twice  as  fast  as  by  hand, 
and  at  about  the  same  cost. 

It  is  also  possible  to  attach  a  motor  of  some  kind  to  a  twist 

*  Oest.  Zeitsclir.f.  B.-  u.  H.-  Wesen,  vol.  xxix.  (1881),  p.  184;  and  vol. 
xxx.  (1882),  p.  103. 

t  Georgi,  "  Die  Diamant-Bohrmaschine  mit  elektrischem  Antriebe  am 
koniglichen  Steinkohlenwerke  zu  Zauckerode,"  Jahrb.  f.  d.  Berg-  und  Hiit- 
tenwesen  im  Konigreiche  Sachsen  auf  das  Jahr  1890,  p.  95. 


i8o 


ORE  AND  STONE-MINING. 


drill  similar  to  Elliott's  hand  tool  already  described.     The  Jeffrey 
Manufacturing  Company,  Columbus,  O.,  have  well-designed  drills 

of  this  class  driven  by  air  or  elec- 
tricity. 

For  working  the  Cleveland  iron- 
stone, Mr.  Steavenson*  is  employing 
twist  drills  driven  by  water-power, 
petroleum  engines  or  electricity.  His 
latest  drill  is  shown  by  Fig.  189  :  A, 
electric  motor ;  B,  hollow  arm  with  a 
shaft  inside  driven  by  A,  and  work- 
ing the  bevel  wheel  C  by  suitable 
gearing ;  D,  twist  drill ;  E,  socket  for 
drill;  F,  universal  joint  connecting 
the  feed-screw  G,  to  the  drill-socket ; 
H,  feed-nut.  Fig.  190  is  a  similar 
drill  worked  by  a  Priestman  petro- 
leum engine.f 

The  cost  per  ton  of  getting  the 
Cleveland  ironstone  has  been  greatly 
reduced  by  the  adoption  of  these 
machines  in  the  place  of  hand-labour  ;. 
but,  as  is  usually  the  case,  the  cost  of 
explosives  per  ton  of  stone  broken  has 
increased,  because  holes  are  bored  so 
easily  and  quickly  that  less  care  is 
taken  in  planning  them.  The  extra 
cost  of  powder  is  more  than  repaid 
by  the  saving  in  labour. 

The  Sprague  Electric  Railway  and 
Motor  Company  of  New  York  J  have 
a  small  electric  rotary  diamond  drill 
for  boring  holes  for  blasting.  The 
motor  is  light  and  carefully  cased  in  to 
preserve  it  from  dust  and  dirt ;  it  is 
mounted  upon  an  adjustable  stretcher 
bar,  and  it  drives  the  drill  direct. 

2.  Percussive  Drills. —  Machine 
drills  are  usually  designed  with  a 
view  of  carrying  out  the  three  opera- 
tions of  hand-work — viz.,  the  blow, 

*  Steavenson,  "  On  the  System  of  Work- 
ing Ironstone  at  Lumpsey  Mines  by  Hy- 
draulic Drills,"  Proc.  N.E.  Inst.  M.  and  M. 
Evg..  vol.  xxxvi.  (1886-87),  p.  67. 

t  Unwin,  "  Petroleum  Engines,"  Proc.  Inst.   C.E.,  vol.  cix.    (1891-92), 
part  iii. 

£  Eng.  Min.  Jour.,  vol.  xlix.  (1890),  p.  in. 


BREAKING  GROUND, 


181 


the  rotation,  and  the  advance.  As  a  rule  a  percussive  drill  consists 
of  a  cylinder  with  a  piston,  which  is  moved  backwards  and  forwards 
by  compressed  air ;  the  cutting  tool  or  chisel  is  firmly  attached 
to  the  piston  rod,  made  specially  strong  to  stand  the  great  amount 
of  shock  to  which  it  is  subjected.  The  rotation  is  almost  always 
effected  by  a  twisted  or  rifled  bar  and  a  ratchet  wheel ;  and,  in 
order  to  keep  the  machine  constantly  in  the  proper  position  for 
work,  it  is  fed  forwards  upon  a  cradle  by  the  workman  behind, 
who  has  merely  to  turn  a  handle,  and  so  cause  a  screw  to  revolve 
inside  a  big  nut  attached  to  the  machine.  Drills  which  will 
advance  automatically  have  been  invented  and  used  in  some 
cases,  but  as  a  rule  nowadays  the  automatic  feed  has  been 
given  up  ;  indeed,  it  seems  quite  unnecessary  to  increase  the 
number  of  the  working  parts  and  make  the  machine  more  com- 
plicated, simply  to  save  the  attendant  the  trouble  of  turning  a 
handle. 

Though  the  plain  chisel-shaped  edge  is  the  commonest  form 
given  to  the  bits  used  with  machine  drills,  it  is  by  no  means  uni- 
versal ;  other  forms  shown  in  the  figures  are  the  cross-bit,  the 


FIG.  191. 


FIG.  193. 


FIG.  194. 


X-bit,  the  Z-bit,  and  the  horse-shoe  bit  (Figs.  191,  192,  193,  and 
194).  The  object  in  all  cases  is  to  secure  a  perfectly  round  hole 
and  so  prevent  jamming.  If  a  band  of  hard  rock  crosses  a  hole 
in  a  slanting  direction,  the  single- edged  bit  is  apt  to  be  diverted 
by  it  slightly,  and  become  fast.  At  the  outset  also,  when  the 
drill  is  striking  an  uneven  surface,  it  is  not  always  easy  to  bore 
the  hole  properly ;  for  this  reason  the  first  drill  is  sometimes 
made  with  the  cross-bit,  whilst  the  remainder  of  the  hole  is  bored 
with  the  single  chisel-edge,  which  will  work  properly  when  the 
hole  is  deep  enough  to  act  in  some  way  as  a  guide  for  the  tool. 

Bits  with  two  or  three  edges  are  not  so  easily  sharpened  as 
those  which  have  but  one  ;  however,  the  work  of  the  smith  may  be 
lightened  by  using  a  swage  (dolly,  U.S.A.),  which  is,  practically, 
a  steel  mould,  into  which  one  end  of  the  steel  bar  is  placed  when 
soft,  whilst  blows  are  struck  upon  the  other  end.  This  gives  the 
proper  shape,  and  the  smith  can  finish  up  the  bit  upon  the  anvil. 


1 82  ORE  AND  STONE-MINING. 

The  adoption  of  the  ingenious-shaped  bars  of  the  Crescent  Steel 
Company  of  Chicago  (Fig.  195)  will  likewise  relieve  the  smith,  but 

the  saving  of  labour  at  the  forge  is 
FIG.  195.  not  the  only  advantage  claimed  for 

the  invention.  The  shaped  steel  will 
discharge  the  debris  more  freely  than 
round  steel,  a  matter  of  no  slight 
importance,  for  the  cleaner  the  hole 
the  more  effective  the  blow  ;  the  little 
chips  should  be  got  rid  of  as  soon 
as  possible,  and  any  means  of  facili- 
tating the  discharge  should  be  welcomed.  A  represents  the 
pattern  made  originally  for  the  iron  mines  of  Lake  Superior,  and 
B  the  section  preferred  in  the  Rocky  Mountains. 

Less  sharpening  is  required  when  boring  by  a  machine  than 
when  boring  the  same  depth  by  hand,  and  for  two  reasons :  first, 
the  bit  suffers  less,  because  the  blow  given  by  the  machine  is 
straighter  and  fairer  ;  and  secondly,  owing  to  the  greater  force 
of  the  blow  work  can  be  done  by  the  tools  when  they  have  become 
very  much  blunter  than  those  which  would  be  put  aside  in  hand- 
drilling.  For  machine-drilling  in  soft  sandstone  in  Ohio,  the 
borer  is  made  with  a  narrow  but  perfectly  flat  bit,  instead  of  being 
chisel-shaped.  A  flat-ended  borer  is  likewise  used  by  the  Inger- 
soll-Sergeant  Rock  Drill  Company  for  boring  elongated  holes  by 
the  Githen  system.  The  tool  does  not  rotate,  and  acts  by  pound- 
ing the  bottom  of  the  hole  to  dust.  The  object  of  the  elongated 
hole  is  to  make  the  rock  rend  along  a  pre-arranged  line,  a  matter 
of  importance  in  quarrying  certain  kinds  of  stone. 

Percussive  drills  may  be  classified  according  to  the  power  used 
for  driving  them,  and  those  worked  by  air  may  be  further  sub- 
divided according  to  the  kind  of  valve  employed  for  reversing 
the  direction  of  the  stroke. 

The  following  table  contains  a  list  of  several  well-known  drills, 
arranged  according  to  their  mode  of  action  and  alphabetically : — 


BREAKING  GROUND. 

PERCUSSIVE  DRILLS. 


183 


Power. 

Kind  of  distributing  valve. 

Name  of  the 
drill. 

/ 

Barrow 

( 

Climax 

/ 

(1)  Valve  worked  by  mechanical    ; 

Dubois  and 

connections         .         .         .  J 

Fran§ois 

Holman 

Rand 

Rio  Tinto 

( 

Bickle 

\ 
(2)  Air-driven  valve    . 

Coles 
Eclipse 

Optimus 

Compressed  air  I 

(3)  Valve  worked  by  mechanical   ) 
connections  and  air  pressure   .    j 

Franke 
Him  ant 

(4)  Two   valves,  a  main  one  air-  "j 

driven,  and   an  auxiliary  one    1 
worked  by  mechanical  connec-   i 

Sergeant 

tions        .         .         .         .         .    ) 

f 

Adelaide 

, 

(5)  No  valve        .        .         .        .  - 

Darlington 

( 

Minera 

Electricity  .     . 

Marvin 

For  the  purposes  of  this  work  it  will  be  quite  sufficient  to  de- 
scribe only  a  few  of  these  machines,  especially  as  in  many 
instances  there  is  a  great  similarity  between  them. 

(i)  The  Barrow  drill*  (Fig.  196)  consists  essentially  of  a  gun- 
Fro.  196. 


metal  cylinder  C,  about  2  feet  in  length  and  4  inches  in  diameter, 
in  which  works  a  cast-steel  piston-rod  D,  fitted  with  two 
pistons  G,  about  1 2  inches  apart,  midway  between  which  is  the 

*  George  Seymour,  "  On  the  Barrow  Rock  Drill,"  Proc.  Min.  Inst.  Corn- 
wall, vol.  i.  (1876-83),  p.  12. 


1 84 


OKE  AND  STONE-MINING. 


tappet  or  boss  G'.  In  a  valve-box  at  the  top  of  the  cylinder  is 
placed  the  oscillating  slide-valve  H  (shown  separately),  pivoted 
at  M ;  it  is  worked  by  the  reciprocation  of  the  tappet  G' 
coming  in  contact  with  its  lower  edges,  which,  for  this  purpose, 
are  sloped  at  each  end,  as  shown. 

There  are  ports,  corresponding  with  openings  in  the  slide-valve 
face,  for  admitting  the  fresh  steam  or  compressed  air  from  the 
inlet  pipe  I  (Fig.  197)  to  the  ports  j  (Fig.  196)  at  each  end  of  the 
cylinder,  and  for  letting  the  spent  or  exhaust  air  or  steam  escape 
by  the  exhaust  pipe  J  (Fig.  197).  This  simple  arrangement  con- 
stitutes the  whole  valve  gear  of  the  machine. 

"  The  borer  is  inserted  into  a  hole  formed  in  the  fore-end  of  the 
piston-rod,  and  is  fixed  therein  by  means  of  a  screw.  Its  rotation  is 
effected  by  hand  by  means  of  the  handle  D"  turning  a  spindle  D', 

FIG.  197. 


which  is  so  fitted  by  means  of  the  cotter  d,  made  fast  in  the  piston 
DG,  and  fitting  in  a  slot  in  the  spindle  D',  that  the  latter  can 
slide  in  the  piston  DG,  but  when  turned  by  the  handle  causes 
the  piston  to  turn  with  it.  The  spindle  D'  has  a  pinion  E,  gear- 
ing into  a  pinion  on  the  adjusting  and  feeding  screw  C',  so 
that  when  the  piston  D  is  turned  by  means  of  the  handle  D",  the 
cylinder  C  is  simultaneously  pushed  along  the  bed-plate  A.  These 
pinions  can  be  easily  disconnected  by  loosening  the  nut  jf,  and 
thus  the  piston  and  the  adjusting  screw  can  be  turned  inde- 
pendently of  one  another  when  required. 

"  The  borers  used  are  respectively  i  J,  i  J,  and  i  inch  in. diameter, 
the  length  of  the  stroke  4  inches,  and  the  maximum  number  of 
blows  about  300  per  minute. 

"  The  gross  weight  of  the  machine,  including  the  bed-plate  and 
gudgeon,  is  about  115  Ibs. 

"  The  bed-plate,  A,  of  the  machine  is  formed  with  a  gudgeon 
A",  which  fits  into  and  can  be  adjusted  to  any  position  in  a  socket 
formed  in  or  on  a  clamp  B',  which  can  be  fixed  on  any  part  of 
the  wrought-iron  box  or  column  B,  thus  forming  a  universal 
joint.  This  bar  or  column  can  be  placed  in  position  either 
horizontally  or  vertically,  as  may  be  most  convenient,  but  is 


BREAKING  GROUND.  185 

generally  placed  across  the  level,  against  the  sides  of  which  it  is 
secured  by  means  of  the  clamp  L,  adjusting  screw  M,  and  claws 
N  and  N'."  Pieces  of  wood  O  O',  are  placed  against  the  wall, 
and  the  claw  is  jammed  against  them  by  screwing  out  the  bar. 

The  Climax  Drill*  (Fig.  198)  recalls  the  Barrow;  A  is  the 
cylinder,  B  B  are  the  two  pistons,  and  C  the  boss  or  swelling  which 
strikes  the  valve  D  and  rocks  it  up  and  down  on  the  centre  pin  E. 
The  valve  has  two  admission  ports,  F  and  F',  which,  when  passing 
corresponding  ports  in  the  valve-chest  face,  allow  the  compressed 
air  to  pass  into  G  or  G'.  On  the  inner  face  of  the  valve,  above  F 
and  F',  there  are  two  recesses,  precisely  similar  to  H  and  H', 
which  control  the  two  ports  on  each  side  of  the  valve-chest  face. 
In  the  position  shown  in  the  figure,  the  compressed  air  could  pass 
from  the  valve-chest  through  F'  into  G'  and  drive  the  piston 

FIG.  198. 


forward,  whilst  the  air  in  the  front  part  of  the  cylinder  would 
escape  by  G,  which  is  now  put  into  communication  with  the 
exhaust  port  by  the  recess  above  F.  The  object  of  the  two  recesses, 
H  and  H',  is  to  enable  the  valve  to  be  reversed  when  one  face  is  worn. 
The  rotation  is  effected  by  a  rifled  bar  I  at  the  back  end  of  the 
cylinder,  which  projects  into  a  long  cavity  K  in  the  rear  piston 
and  piston  rod.  It  can  be  turned  easily  in  one  direction,  but  is 
prevented  from  moving  in  the  opposite  direction  by  the  teeth  of  a 
crown  ratchet  clutch  L,  a  device  which  is  thought  by  the  maker 
to  offer  a  better  guarantee  against  injury  than  the  ratchet  wheel 
with  one  or  two  pawls  common  in  most  other  drills.  When  the 

*  Figures  and  descriptions  of  the  Bickle,  Climax,  Coles,  Daw,  Eclipse, 
Ingersoll,  and  Kio  Tinto  drills  will  be  found  in  a  paper  by  Carbutt  and 
Davey,  "  On  Recent  Trials  of  Rock  Drills,"  Min.  Proc.  List.  Meek.  Eng., 
London,  March  1891. 


1 86 


OKE  AND  STONE-MINING. 


piston  moves  forward,  the  nut  in  the  rear  piston  passes  over  the 
rifled  bar,  and  causes  it  to  turn  round,  but  when  the  motion 
of  the  piston  is  reversed  the  rifled  bar  is  prevented  from  turning 
by  the  ratchet  clutch,  the  piston  is  forced  to  rotate,  and  with 
it  the  borer.  M  is  the  feed-screw  worked  by  a  handle  not  shown 
in  the  figure,  and  N  the  feed-nut. 

The  Dubois  and  Francois  Boring  Earn  (Bosseyeuse)*  is  a  machine 
of  a  totally  different  type  (Figs.  199  and  200) ;  it  bores  large  holes 
for  the  insertion  of  a  wedge,  and  it  is  fitted  with  a  ram  for  driving 
in  the  wedge,  and  so  breaking  the  rock. 

The  machine  has  been  specially  designed  for  driving  levels  in 
mines  where  there  is  so  much  fire-damp  as  to  render  blasting 

FIGS.  199  &  200. 

>.  Elevation 

§ 
A 


SCALE   Of   FEET 


dangerous,  and  it  therefore  more  especially  concerns  collieries 
than  ore  and  stone  mines ;  but  it  should  be  mentioned  in  connec- 
tion with  the  latter,  because  it  will  also  bore  holes  for  blasting, 
and  because  it  is  sometimes  used  for  cutting  a  series  of  holes,  and 
so  creating  a  first  opening,  which  enables  blasting  to  be  conducted 
with  greater  advantage  (Fig.  239). 

The  boring  cylinder,  A,  has  a  long  piston  B,  with  spiral  grooves 
which  produce  the  rotation  by  means  of  a  ratchet  wheel  C,  whilst 
the  slide-valve,  which  effects  the  distribution,  lies  in  the  valve- 
chest  F,  and  is  brought  into  action  when  a  swelling,  D,  on  the 
piston-rod  touches  a  bent  lever  E. 

The  borer,  G,  is  fixed  in  the  end  of  the  piston-rod,  and  makes 
a  hole  3  or  4  inches  in  diameter.  As  the  hole  is  deepened,  the 

*  Mathet,  L'air  comprimt  aux  mines  de  Blanzy,  Saint-Etienne,  1889,  p.  66. 


BREAKING  GROUND.  187 

cylinder  is  made  to  travel  along  the  frame,  H,  by  means  of 
a  screw,  and  at  the  same  time  the  counterpoise,  I,  is  also  moved 
by  a  screw  so  as  to  balance  it.  The  machine  can  be  made  to  turn 
round  the  central  column,  and  can  also  be  moved  in  a  vertical 
plane,  so  that  holes  may  be  bored  in  any  direction ;  and  the 
special  carriage  in  use  at  the  Blanzy  mines  permits  the  machine 
to  be  moved  laterally,  and  take  a  position  near  the  side  of  the 
tunnel. 

The  whole  machine  is  very  heavy,  weighing  no  less  than  2  tons 
13  cwt.  (2700  kil.);  but  it  is  found  that  the  greater  power  and 
stability  so  obtained  fully  compensate  for  any  inconvenience 
caused  by  its  weight. 

At  Blanzy  one  boring  ram  has  taken  the  place  of  four  small 
drills  mounted  upon  one  stand ;  and  this  diminution  in  the 
number  of  machines  requiring  attention  is  no  inconsiderable 
advantage. 

An  ingenious  contrivance  used  with  the  Blanzy  boring  ram 
must  on  no  account  be  passed  over — viz.,  the  special  pipe  for  con- 
veying water  to  the  bottom  of  the  bore-hole.  A  small  copper 
tube  (L,  enlarged  cross-section,  Fig.  200)  lies  in  a  groove  in  the 
borer,  and  carries  in  a  jet  of  water  which  keeps  the  bit  or  boring 
edge  quite  cool,  and  washes  out  all  the  chippings  as  soon  as  they 
are  produced.  The  tool  is  thus  enabled  to  work  fairly  and  freely 
the  whole  time,  and  the  result  at  Blanzy  has  been  a  great  increase 
both  in  the  speed  of  boring  and  in  the  duration  of  the  bits. 

The  water  is  supplied  to  the  drill  by  the  india-rubber  pipe  J, 
which  leads  to  the  hollow  collar  K.  The  collar  is  fixed  with  a 
water-tight  joint  upon  the  drill  socket,  so  that  the  latter  can 
revolve  freely.  The  water  finds  its  way  through  a  hole  in  the 
drill-socket  to  the  outside,  when  a  short  piece  of  india-rubber 
tube  takes  it  to  the  copper  pipe.  The  collar  is  kept  in  one  posi- 
tion either  by  a  weight  hanging  down  from  it,  or  by  a  rod  which 
moves  forwards  with  the  machine.  Care  is  taken  to  pass  the 
supply  of  injection  water  through  wire  gauze,  to  remove  any 
matter  which  might  choke  the  small  copper  tube. 

When  the  necessary  holes  have  been  bored,  the  drill  is  taken 
off  and  replaced  by  a  strong  ram  or  hammer-head,  which  is  made 
to  strike  powerful  blows  upon  a  wedge  between  two  feathers 
fitting  into  the  hole.  Large  masses  of  rock  are  broken  off  in 
this  way,  and  the  level  is  driven  with  any  required  dimensions. 

» (2)  The  American  Ingersoll  Sergeant  Eclipse  Drill  (Fig.  201)  may 
be  taken  as  an  example  of  the  machines  having  the  valve  worked 
by  differences  of  air-pressure,  which  are  caused  by  the  opening  and 
closing  of  certain  passages  by  the  piston  in  its  course.  It  consists 
of  the  following  main  parts  :  the  cylinder  A,  the  piston  M,  the 
piston-rod  B,  and  the  valve  chest  C.  The  valve  is  like  a  D-slide- 
valve,  but  its  face  is  turned  so  as  to  fit  the  cylindrical  interior  of 
the  valve-chest,  and  it  is  provided  at  each  end  with  a  piston.  It 


J  mi 


1 88  OEE  AND  STONE-MINING. 

therefore  has  the  form  of  a  spool  or  reel  enclosing  a  D-slide- valve, 
and  it  moves  backwards  and  forwards  on  a  guide-pin.  The  air 
enters  the  valve-chest  at  0,  and,  when  the  piston  has  reached  the 
position  shown  in  the  figure,  it  finds  its  way  round  the  valve  to 
N',  enters  the  port  P',  and  finally  reaches  the  rear  end  of  the 
cylinder  ;  when  the  valve  is  reversed,  it  goes  past  N  into  P,  and 
to  the  front  end  of  the  cylinder.  The  port  P  is  shown  in  the 
figure  communicating  by  the  slide-valve  with  the  exhaust  E. 
The  letters  S  S'  represent  a  shallow  recess  cut  round  the 
piston,  in  reality  making  one  piston  into  two  ;  F  F'  are  two  ports 
leading  to  the  exhaust,  and  lastly  D  D'  are  two  small  ports  which 

FIG.  201. 


communicate  crosswise  with  the  ends  of  the  valve-chest;  that 
is  to  say,  D  is  connected  with  the  end  II',  and  D'  with  the 
end  E-. 

Bearing  these  details  of  construction  in  mind,  the  action  of  the 
drill  can  be  followed.  The  drawing  shows  the  machine  ready  to 
begin  its  forward  stroke.  The  rear  end  of  the  valve-chest  is  con- 
nected with  D,  which  is  closed  by  the  piston,  whilst  the  front  E, 
is  open  through  D'  and  the  annular  recess  S  to  the  port  F'  and 
the  atmosphere.  The  compressed  air  from  0  leaking  past  the 
rear  valve-piston  presses  upon  it  and  keeps  it  in  the  position 
shown,  for  any  air  leaking  past  the  other  valve  piston  at  the  end 
K  can  escape  vid  D',  S,  F'  and  E  into  the  atmosphere. 

We  will  now  suppose  that  the  main  piston  M  is  being  driven 
forward  by  the  pressure  behind  it ;  the  annular  space  S  gradually 
approaches  the  port  D,  but  the  length  of  the  groove  is  so  arranged 
that  D'  becomes  closed  just  before  D  is  opened  to  the  exhaust. 
When  the  new  state  of  things  has  arisen — that  is  to  say,  when  D  is 
open  to  the  exhaust  and  D'  closed — the  pressure  in  the  space  II' 
at  once  drops  to  that  of  the  atmosphere,  and  the  valve  is  driven 
across  by  the  pressure  upon  the  piston  at  the  end  R. 

At  both  ends  of  the  cylinder  there  is  a  strong  india-rubber 
washer,  protected  by  a  steel  washer,  which  is  represented  by  a 
black  line.  If  the  miner  fails  to  feed  his  machine  forward  pro- 
perly, the  elasticity  of  the  washer  prevents  the  end  of  the  cylinder 
from  being  broken.  The  rotation  is  performed  by  the  usual 
rined  bar  and  ratchet  wheel,  and  the  machine  is  advanced  by 


BREAKING  GROUND. 


189 


FIGS.  202 


INCHES 


turning  the  handle  and  so  causing  the  carrying  nut  to  move 
along  the  feed  screw. 

The  Optimus  drill,  invented  by  Ogle,  has  two  pistons,  a  large 
one  in  front  and  a  small  one  behind.  The  compressed  air,  after- 
acting  at  the  rear  end  and  making 
the  tool  strike  its  blow,  is  led  to 
the  front  end  of  the  cylinder,  and 
pressing  upon  the  large  piston 
drives  it  back.  The  inventor  claims 
considerable  economy  for  his  drill, 
because  the  backward  stroke  is  made 
with  air  which  usually  goes  direct 
to  the  exhaust. 

Figs.  202  and  203  show  one 
method  of  attaching  the  drills  to 
the  piston-rod.  A  is  the  piston- 
rod  with  an  enlarged  head,  H ;  S  is 
the  shank  of  the  tool  which  is 
gripped  in  the  socket  by  a  chucking  block  fj,  tightened  by  a 
U-shaped  clamping-bolt  0. 

(3)  Franke  drill*  This  drill  (Fig.  204)  is  especially  interesting 
from  being  the  smallest  and  lightest  boring  machine  in  actual  use. 
Including  the  borer,  it  weighs  only  16  Ibs.  (yj  kil.),  and  it  may, 
therefore,  be  placed  at  one  end  of  the  scale  whilst  the  ponderous 
"  bosseyeuse "  of  Dubois  and  Frangois  occupies  the  other.  Both 
in  his  drill  and  in  his  mechanical  chisel,  Franke  adopts  the  prin- 
ciple of  doing  the  work  by  a  light  blow  repeated  very  rapidly 
indeed,  instead  of  a  heavy  blow  at  less  frequent  intervals. 

The  principal  parts  of  the  machine  are  : — A,  outer  case  or  shell ; 
J.',  cylinder  proper ;  JB,  piston  ;  (7,  ring-shaped  slide-valve,  which 
can  slide  backwards  and  forwards  in  a  short  recess  in  the  piston  ; 
1},  tool-holder ;  JS,  pipe  bringing  air ;  ft  rear  end  of  cylinder 
proper  with  admission  ports ;  G,  spiral  spring ;  N,  exhaust 
port ;  V,  piston-rod ;  J,  striking  head  of  piston-rod  ;  P,  pin  passing 
through  the  piston-rod  •  a,  passage  bringing  air  from  F ;  6,  port 
admitting  air  to  slide-valve ;  c,  one  of  three  longitudinal  passages 
connecting  the  front  end  of  the  piston  with  the  annular  recess 
in  which  the  slide-valve  works ;  e,  one  of  three  similar  passages 
connecting  the  same  recess  with  the  rear  end  of  the  piston; 
f,  hollow  centre  of  piston  and  piston-rod  communicating  by  g  with 
the  exhaust  port  H  •  h  h,  two  of  the  three  radial  passages  which 
put  the  slide-valve  0  into  connection  withy";  i,  part  of  tool-holder ; 
j,  collar  preventing  the  tool-holder  from  being  driven  back  too 
far ;  llv  straight  slots  in  the  shell  A  •  o  ov  oblique  slots  in  the 

*  Schrader,  "  Die  neueren  Fortschritte  bei  derAnwendung  von  Gesteins- 
Bohrmaschinen  und  die  Versuche  mib  kleinen  Schrammaschinen  beim 
Mansf elder  Kupferschieferbergbau,"  Zeitschr.  f.  B.-  H.-  u.  £-  Wesen,  vol. 
xli.,  1893,  p.  1 10. 


190 


ORE  AND  STONE-MINING. 


hollow  cylinder  q ;   qv  end  of  the  cylinder  q  ;  r  rv  ends  of  the 
pin  P ;  tt,  pawls  attached  to  ql ;  u,  hexagonal  end  of  the  tool- 


j! 


<0 

3 

i 

-:       o 

5     z 

0 

<v*      "l£f 


0) 


holder  D ;  v,  ratchet  wheel,  which  can  slide  upon  u  but  cannot 
rotate  without  it. 

After  this  description  of  the  parts,  the  mode  of  action  of  the 


BREAKING  GROUND. 


191 


machine  can  be  easily  understood.  The  air  is  brought  by  a  flexible 
hose  attached  to  E,  and  passing  along  the  small  passages  a  outside 
the  cylinder  proper,  enters  it  at  b.  In  the  position  shown  in  the 
figure  the  lower  b  allows  the  air  to  pass  into  e,  press  upon  the 
rear  end  of  the  piston,  and  drive  it  forwards.  During  this  time 
the  air  in  front  of  the  piston  has  an  escape  provided  by  the  passages 
c,  h,  f,  and  g  to  the  exhaust  port  H.  The  complete  stroke  is 
20  mm.  (^  inch),  and  when  the  piston  has  travelled  17  mm., 
the  end  of  the  piston  rod  «7  strikes  the  head  u,  and  the  tool 
does  its  work  at  the  bottom  of  the  hole,  provided  of  course  that 
the  machine  is  properly  held.  As  the  piston  goes  forwards  it 
draws  the  slide-valve  C  with  it ;  as  soon  as  0  has  passed  the  port 
&,  it  is  driven  across  the  recess  and  the  direction  of  the  air  is 
reversed.  The  front  end  of  the  cylinder  is  now  in  communication 
with  the  compressed  air,  whilst  the  space  at  the  rear  end  dis- 
charges its  contents  vid  e,  C,  h,  /,  and  g  into  H.  The  slide-valve 
C  is  then  again  shot  across,  and  air  is  admitted  to  the  rear  end  of 
the  piston.  The  end  of  the  piston-rod,  J,  is  therefore  constantly 
hammering  upon  u,  and  after  each  blow  the  spring  G  brings  the 
tool-holder  back  to  its  original  position.  The  rotation  of  the  tool 
is  effected  in  a  simple  manner.  The  ends  r  rt  of  the  pin  P  are 
forced  to  travel  in  a  direct  line  by  the  slots  I  \  ;  but  the  slots  o  ol 

FIG.  205. 


are  oblique,  and  the  pin  P,  therefore,  causes  the  hollow  cylinder  q 
to  oscillate.  During  the  forward  stroke  each  pawl,  t,  is  drawn 
over  a  tooth  of  the  ratchet  wheel  v ;  during  the  back  stroke  it 
turns  v  slightly,  and  with  it  the  tool-holder. 


ORE  AND  STONE-MINING. 


The  borer  is  made  of  round  steel  §  inch  (15  mm.)  in  diameter, 
with  a  Z-shaped  bit  i  inch  (25  mm.)  wide.     The  number  of  blows 

has  not  yet  been  determined 
exactly;      but     it     probably 
reaches    8000    to    10,000  per 
minute.      The   moving   parts 
of  the  machine  are  constructed 
of  soft  tough  steel,  except  the 
slide  -  valve,    for    which     good 
wrought  iron  appears  at  present 
to  be  the  most  suitable  material. 
The  machine  is  used  without 
any  stand,  and  is  simply  held  in 
the  hands  (Fig.  205,  man  in  a 
kneeling  posture).* 

The  Hirnant  drill']'  of  Messrs, 
Larmuth  &  Co.  is  a  machine  with 
a  tappet  valve  assisted  by  air- 
pressure.  In  Fig.  206,  A  is  the 
cylinder,  B  the  piston,  and  C 
the  valve-chamber  containing  a 
piston-valve  D,  which  works  over 
the  admission  ports  E  and  E', 
and  the  exhaust  ports  F  and  F'. 
G  is  a  tappet,  oscillating  upon 
the  pin  H,  when  the  noses  /  and 
K  are  struck  by  the  curved 
shoulders  L  and  M  of  an 
annular  recess  N  around  the 
.piston  E. 

In  the  position  of.  the  parts 
as  figured,  the  compressed  air 
brought  into  the  valve-chamber 
is  passing  through  E'  to  the  rear 
end  of  the  cylinder,  whilst  the  air 
in  front  is  in  communication  by 
E  and  F  with  the  exhaust.  At 
the  same  time  the  air  is  also 
pressing  upon  the  rear  end  of  the 
piston-valve,  for  it  escapes  along 
the  passage  O'P'  made  by  planing 
flat  surfaces  upon  the  valve  and 
the  inside  of  the  end  of  the  cham- 
ber. The  other  end  of  the  valve 


*  From  a  photograph  supplied  by  the  makers,  Messrs.  Friemann  and 
Wolf.  Zwickau, 
t  Patent  Office  Specification  No.  10,050,  A.D.  1891. 


BREAKING  GKOUKD. 


chest  is  put  into  communication  with  the  exhaust  by  the  small 
port  Q,  and  as  the  flat  surfaces  P  and  0  are  not  overlapping, 
there  is  no  passage  of  compressed  air.  The  pressure  upon  the 
rear  end  of  the  valve  D  therefore 
tends  to  move  it  forwards,  and  assists 
in  moving  it  forwards,  the  moment 
that  the  nose  /  can  drop  down  owing 
to  the  recess  N  passing  under  it.  The 
shoulders  L  and  M  would  of  them- 
selves move  the  tappet,  but  the 
auxiliary  air  pressure  has  the  advan- 
tage of  reversing  the  valve  without 
the  shocks  which  are  so  destructive 
to  the  tappets  of  many  drills.  The 
cushion  of  air  in  the  space  K'  pre- 
vents the  nose  K  of  the  tappet  G 
from  striking  the  recessed  part  N 
of  the  piston. 

The  long  valve-chest  has  the  ad- 
vantage of  shortening  the  inlet  ports, 
and  so  making  a  saving  in  the  con- 
sumption of  compressed  air.  t^. 

This  drill  is  further  provided  with    N 
a  device  for  taking  up  any  slackness    o 
of  the  feed-screw  and  feed-nut  due  ^ 
to  wear.     S  is  the  feed-screw  and  T 
the  main  feed -nut,  placed  between    ' 
the  two  lugs  U  and  U'9  forming  part/ 
of  the  same  casting  as  the  cylinder. 
T'  is  a  second  nut,  and  between  T' 
and  T  there  is  a  space  V  in  which  is 
fitted  a  spiral  spring.    T'  is  prevented 
from  turning  by  having  a  flat  face 
resting  against   the   cylinder  cover. 
When  the  feed-screw  and  the  nuts 
wear,  T7  is  forced  away  from  T  by  the 
spring  and  the  slackness  is  remedied. 

Z  is  a  collar  upon  a  stirrup  at- 
tached to  the  cradle,  and  furnishes  a 
point  d'appui  for  the  advance  of  the 
machine  when  the  screw  S  is  turned 
by  the  handle. 

(4)  The  Sergecvnt  drill  has  the 
peculiarity  of  having  two  valves,  a  main  valve  and  .  an  auxiliary 
valve ;  the  latter  is  moved  backwards  and  forwards  by  inclines  or 
shoulders  upon  the  piston,  and,  by  controlling  certain  air-passages, 
it  causes  differences  of  pressure  which  drive  the  former. 

In  Fig.  207  a  is  the  cylinder,  b  the  piston  with  an  annular  recess 

N 


1 94  ORE  AND  STONE-MINING. 

turned  in  it  presenting  two  inclined  shoulders ;  c  is  the  valve-chest 
into  which  the  compressed  air  enters  from  one  of  the  sides ;  d  is 
the  main  valve,  and  as  it  moves  to  and  fro  it  alternately  places  the 
port  e  or  /  in  communication  with  the  exhaust  g ;  e  leads  to  the 
port  h  and  to  the  front  end,  and  J-  to  the  port  i  and  to  the  rear 
end  of  the  cylinder ;  j,  the  auxiliary  valve,  is  a  slide-valve  made  in 
the  form  of  a  segment  of  a  circle,  and  having  a  recess  in  one  of 
its  flat  faces.  It  is  slightly  longer  than  its  arc-shaped  seat,  so 
that  one  end  of  it  always  projects  into  the  cylinder.  The  pro- 
jecting end  of  the  valve  is  caught  by  the  corresponding  shoulder 
of  the  piston  as  it  passes,  and  it  is  thus  being  constantly  knocked 
backwards  and  forwards.  By  means  of  its  recess  this  segmental 
slide-valve  puts  the  ports  k  and  I  alternately  into  communication 
with  the  port  M,  which  opens  into  the  exhaust.  The  port  k  leads 
to  the  front  end  of  the  valve-chest,  the  port  I  to  the  rear  end ; 
consequently  the  two  ends  are  being  alternately  placed  in  com- 
munication with  the  exhaust.  The  compressed  air  leaking  past 
the  piston-like  ends  of  the  main  valve  escapes  into  the  exhaust  at 
one  end  of  the  valve-chest,  but  exerts  a  pressure  at  the  other  end 
where  it  is  confined,  and  so  throws  the  main  valve  over,  changing 
the  direction  in  which  the  air  is  being  admitted  into  the  cylinder. 
The  piston  makes  its  stroke,  knocks  over  the  auxiliary  valve, 
which  in  its  turn  releases  the  pressure  at  one  end  of  the  main 
valve  and  causes  it  to  move  across  once  more. 

The  rotation  is  effected  by  a  rifled  bar,  n,  as  usual ;  but  instead 
of  there  being  a  ratchet-wheel  fixed  to  this  bar  with  pawls  attached 
to  the  cylinder,  the  rifled  bar  carries  the  pawls  which  work  inside 

a  ratchet-wheel,  o,  with  in- 

FIG.  208.  ternal  teeth  and  a  smooth 

exterior  (Fig.  208).  The 
pawls  are  pressed  out  by 
springs,  p  (Fig.  207).  So 
far  the  action  is  very  like 
that  of  other  drills,  save  that 
the  pawls  move  round  inside 
the  wheel,  instead  of  the 
wheel  moving  round  under 
the  pawls.  The  special 
peculiarity  of  the  Sergeant  rotating  device  is  the  mobility  of 
the  wheel  if  the  drill  jams  in  a  hole.  The  ratchet-wheel  o  lies 
loose  in  a  recess  behind  the  cylinder,  and  in  ordinary  working  is 
pressed  sufliciently  firmly  against  the  end  of  the  cylinder  by  steel 
cushion  springs  to  make  the  piston  rotate  without  turning  itself  ; 
but  if  for  some  reason  the  borer  jams  in  the  hole  and  causes  a 
strain  upon  the  rifled  bar,  the  wheel  is  capable  of  turning  and  so 
preventing  a  breakage. 

The  feed  as  usual  is  by  hand ;  q  is  the  handle  working  the  feed- 
screw r  in  the  feed-nut  s. 


BREAKING  GROCHSD.  195 

(5)  In  the  drills  of  this  class  the  piston  performs  a  double  '' 
function ;  it  not  only  acts  as  a  medium  for  receiving  the  pres- 
sure of  the  air,  but  it  also  itself  uncovers  or  closes  the  passages  V 
by  which  the  air  enters  or  escapes,  and  so  causes  a  reversal  of 
the  stroke  without  the  intervention  of  any  separate  valve. 

The  Adelaide  drill  (Fig.  209)  comes  first  alphabetically,  although 


it  was  preceded  in  time  by  the  Darlington  drill,  of  which  it  may 
be  regarded  as  a  modification.  A  A  represent  the  annular  port, 
admitting  the  air  all  round  the  piston,  and  B,  Bt  are  ports  in  the 
piston-rod.  When  the  latter  are  opposite  A  A,  air  passes  down 
through  the  space  C  in  the  piston-rod  to  the  rear  end  of  the 
piston,  and  drives  it  forward  till  it  uncovers  the  port  £,  which 
puts  this  part  of  the  cylinder  into  communication  with  the 
atmosphere.  At  the  same  time  Bt  Bt  have  passed  beyond  the 
stuffing-box  and  part  of  the  exhaust  escapes  in  that  direction ; 
while  this  is  happening  the  long  shallow  annular  recess  cut  in 
the  piston-rod  is  brought  to  A,  the  air  presses  on  the  small 
annular  space  at  the  front  end  of  the  piston  and  drives  it  back. 
It  will  be  noticed  that  this  drill  uses  the  air  expansively,  for 
when  once  Bt  has  gone  past  A  no  further  supply  of  power  is  taken 
in.  D  is  the  rifled  bar,  E  the  ratchet  wheel,  H  the  feed-screw, 
and  G  the  feed-nut,  similar  to  the  corresponding  parts  of  many 
other  machines. 

The  construction  of  the  Darlington  drill  will  be  understood  by 
referring  to  Figs.  210,-  211,  and  212;  a  is  the  cylinder;  b  the 
piston-rod ;  c  the  borer ;  d  d  are  two  openings  for  bringing  in 
compressed  air,  either  of  which  may  be  used  according  to  the 
position  of  the  drill ;  e  is  the  inlet  hose  with  a  stop-cock ;  /,  drill- 
holder  ;  f/9  stretcher-bar  ;  h,  piston  ;  j,  rifled  bar  for  turning  piston 
and  drill ;  &,  ratchet  wheel  attached  to  rifled  bar  ;  I,  rifled  nut 
iixed  in  the  piston  head ;  m,  wood  for  lessening  weight  of  piston 
rod  and  blocking  space  ;  M,  portway  for  allowing  the  compressed 
air  to  pass  to  the  rear  of  the  piston  and  give  the  blow  ;  o,  exhaust 
portway.  The  action  of  the  drill  is  as  follows  : — The  compressed 
air  is  always  acting  on  the  front  end  of  the  piston,  and  Avhen 
the  rear  end  communicates  with  the  outer  atmosphere,  the 
piston  moves  rapidly  backwards  and  uncovers  the  portway  n. 
The  compressed  air  rushes  through  and  presses  against  the  rear 


1 96  ORE  AND  STONE-MINING. 

FIG.  210.  FIG.  211. 


BREAKING  GROUND. 


,197 


end  of  the  piston,  which  has  a  greater  area  than  the  front 
end,  the  difference  being  equal  to  the  section  of  the  piston-rod. 
The  piston  is  driven  rapidly  forwards,  and  the  drill  strikes  its 
blow.  At  the  same  time  it  uncovers  the  exhaust  port  o,  and 
then  the  constant  pressure  on  the  annular  area  on  the  front 
end  of  the  piston  produces  the  return  stroke.  The  number  of 
blows  per  minute  is  from  600  to  800.  The  rotation  of  the  drill 
is  effected  by  the  rifled  bar.  On  the  forward  stroke  of  the  piston, 
the  bar  with  its  ratchet-wheel  is  free  to  turn  under  a  couple  of 
pawls,  and  consequently  the  piston  moves  straight  whilst  the  bar 
and  ratchet-wheel  turn.  When  the  back  stroke  is  being  made, 

FIG.  212. 


the  ratchet-wheel  is  held  by  the  pawls  and  the  piston  is  forced  to 
make  part  of  a  revolution.  As  the  hole  is  deepened  the  cylinder 
is  advanced  forwards  by  turning  the  handle  p  ;  this  works  an 
endless  screw,  #,  passing  through  a  nut  attached  to  the  cylinder ;  r 
is  the  cradle  carrying  the  feed-screw  and  supporting  the  cylinder. 
It  is  centered  on  the  clamp  s.  As  this  clamp  can  be  fixed  in 
any  position  on  the ,  bar,  and  as  the  cradle  can  be  turned  on  the 
clamp,  it  is  evident  that  holes  can  be  bored  in  any  direction. 

In  driving  a  level  with  a  Darlington  drill,  it  is  usual  to  fix  the 
stretcher-bar  horizontally  so  as  to  command  the  upper  part  of 
the  face ;  holes  can  then  be  bored  with  the  cradle  above  the  bar 
or  below  it.  The  bar  is  then  shifted  low  enough  to  bore  the 
bottom  holes.  It  is  found  that  all  the  necessary  holes  can  be 
bored  from  these  two  positions  of  the  bar. 

The  bar,  therefore,  has  to  be  fixed  only  twice;  the  shifting 
of  the  machine  for  boring  holes  in  various  directions  is  managed 


198  ORE  AND  STONE-MINING. 

by  sliding  or  turning  the  clamp  on  the  bar  and  by  moving  the 
cradle  on  the  clamp. 

Fig.  212  shows  the  stretcher-bar  fixed  in  a  vertical  position, 
which  is  sometimes  convenient. 

In  order  to  keep  the  holes  clear,  a  jet  of  water,  supplied  from 
a  hose  attached  to  a  J-inch  gas-pipe  leading  from  a  cistern  at  a 
higher  level,  is  made  to  play  into  them  during  the  process  of 
boring. 

For  sinking  shafts,  Mr.  Darlington  has  the  drill  fixed  in  a 
cylindrical  case  with  a  large  external  thread,  which  works  in  a 
nut  on  the  clamp.  The  drill  is  fed  forwards  by  turning  a  hand- 
wheel  attached  to  the  case. 

The  Marvin  Drill  *  of  the  Edison  General  Electric  Company  is 
based  upon  the  principle  that  a  spiral  coil  of  wire  assumes  magnetic 
properties  when  a  current  is  passed  through  it,  and  becomes 
capable  of  exerting  a  very  strong  attraction  upon  a  bar  of  iron 
placed  in  a  suitable  position.  The  actual  working  parts  of  the 

drill  are  shown  in   Fig.   213. 

FIG.  213.  A  and  B  are  two  hollow  coils 

of  copper  wire  (solenoids), 
through  which  passes  the  rod 
C  D.  The  two  ends  are  made 
of  bronze,  but  the  central  por- 
tion, E  F,  is  of  iron.  At  the 
end  C  there  is  a  socket  for 
receiving  the  tool,  whilst  the 
end  D  is  rifled  and  works  in  a 
ratchet-wheel,  and  so  effects 

the  rotation  in  the  usual  way.  A  current  is  led  to  the  drill  by  a 
cable  with  three  wires,  shown  separately  by  G,  H,  and  I,  and  by 
means  of  a  very  simple  revolving  armature  on  the  dynamo  it  can 
be  made  to  pass,  first  through  one  solenoid,  and  then  through  the 
other,  in  each  case  returning  by  the  wire  H.  For  instance, 
we  may  suppose  that  the  current  is  passing  through  the  front 
solenoid ;  this  becomes  magnetic  and  draws  the  iron  core  for- 
wards, and  so  causes  the  tool  to  strike  a  blow.  The  current  is  then 
reversed  by  the  revolution  of  the  armature,  and  flows  into  the 
solenoid  B,  which  in  its  turn  becomes  magnetic  and  draws  the 
iron  back,  for  A  has  lost  its  magnetic  power.  The  rear  end  of 
the  rod  C  D  is  made  to  compress  a  spring,  and  so  store  up 
force  which  is  utilised  in  increasing  the  strength  of  the  forward 
blow. 

The  drill  makes  600  strokes  a  minute,  and  is  said  to  be  capable 
of  boring  in  granite  at  the  rate  of  2  inches  a  minute. 

At  the  present  time  there  are  few,  if  any,  electric  percussive 
drills  in  regular  use  in  mines,  one  objection  to  them  being  their 

*  "Electric  Percussion  Drills,"  Eng.  Min.  Jov.r.,  vol.  li.  (1891),  p.  609. 


BREAKING  GROUND.  199 

great  weight  compared  with  air  drills  of  equal  strength ;  but  it  is 
stated  that  they  are  doing  good  work  at  some  open  limestone 
quarries  at  Syracuse,*  N.Y. 

IV.  Machines  for  Cutting  Grooves. — In  working  a  seam 
the  task  of  the  miner  frequently  consists  in  cutting  a  deep 
groove  parallel  to  the  bedding  with  a  pick,  and  so  laying  it  bare 
above,  below,  or  in  the  middle.  Wedging  or  blasting  will  then 
break  it  away. 

The  first  machines  for  cutting  grooves  very  naturally  imitated 
the  miners'  tools,  and  were  simply  mechanical  picks,  but  since 
then  many  other  groove  cutters  have  been  applied  which  are  based 
upon  different  principles. 

They  may  be  classified  as  follows : — 

1.  Mechanical  picks,  chisels,  and  gouges. 

2.  Travelling  jumpers  and  rock-drills. 

3.  Circular  saws. 

4.  Endless  chains  with  cutters  attached. 

5.  Wire  saw. 

6.  Kevolving  toothed  bar. 

(i)  Mechanical  Picks,  &c. — Some,  like  Firths  machine j 
swing  a  pick  like  a  miner.  The  Sergeant  machine  is  a  strong  rock 
drill  with  a  chisel  bit,  which  chips  out  a  groove  as  a  carpenter 
might  cut  out  a  mortice.  It  is  mounted  on  two  wheels  and  can 
be  handled  with  ease.  Carrett  and  Marshall's  machine  is  a  power- 
ful gouge,  worked  by  hydraulic  pressure,  which  cuts  out  a  groove 
in  coal  or  soft  rocks.  These  have  all  been  designed  more  especially 
for  the  collier ;  but  in  Frankds  mechanical  chisel  (Fig.  214)  we 
have  a  tool  which  is  being  successfully  employed  in  ore-mining. 
It  is  based  upon  the  principle  of  striking  a  very  large  number 
of  short  and  light  blows  instead  of  a  comparatively  small  number 
of  long  arid  heavy  ones.  It  resembles  in  some  respects  Crossley's 
mechanical  caulking  tool  and  McCoy's  chisel. 

The  following  description  is  derived  from  accounts  given  by 
Pilaf  and  Schrader,f  and  from  personal  observations  at  Mansfeld; 
a  is  the  outer  shell  of  the  machine,  b  the  inner  or  real  cylinder,  c  the 
piston  with  the  annular  slide-valve  r,  d  the  tool-holder  carrying 
the  chisel  in  a  deep  socket ;  the  air  is  brought  in  to  a  by  the  pipe 
t,  and  finds  its  way  into  b  through  four  broad,  low  passages,  mi  in, 
and  sixteen  small  ports,  similar  to  n  n,  T^  inch  in  diameter.  The 
front  part  of  the  outer  shell,  a',  serves  as  cylinder  cover  and  as 
guide  for  the  piston  rod,  and  lastly  to  contain  the  tool-holder  d, 
surrounded  by  two  spiral  springs  in  the  space  between  the  shoulder 
p,  and  the  cover  s.  The  opening,  o,  allows  the  air  to  escape  in 
front  of  the  piston-rod,  and  so  makes  the  stroke  easier ;  I  is  the 
exhaust  port,  and  q  a  hole  for  lubricating ;  r  is  the  ring  valve, 

*  Eng.  Min.  Jour.,  vol.  Iv.  (1893),  P-  491- 

t  Johann  Pilaf,  "  Schrammeissel,  System  Franke,  im  Mansfeldischen," 
Oest.  Zeitschr.  B.-  u.  H.-  W.,  vol.  xl.  (1892),  p.  78.  Schrader,  op.  cit.  p.  171. 


200 


ORE  AND  STONE-MINING. 

FIG.  214. 


BREAKING  GROUND.  201 

sliding  upon  the  piston,  and  as  soon  as  it  is  drawn  past  the  port 
n,  it  is  driven  either  forwards  or  backwards  by  the  air  pressure. 
In  the  position  shown  in  the  figure,  representing  the  end  of 
the  return  stroke,  the  valve  r  has  been  driven  back,  and  the  air 
is  enabled  to  pass  from  m  into  g,  and  so  to  the  back  of  the  piston. 
The  air  in  the  space  in  front  of  the  piston  finds  an  exit  along  the 
three  passages  h,  of  which  only  one  can  be  shown  in  the  section, 
and  entering  the  annular  slide-valve,  is  brought  by  one  of  the 
three  radial  passages,  i,  into  the  hollow  central  p&rtjk  of  the 
piston  and  piston-rod,  and  eventually  to  the  exhaust  I.  As  soon 
as  the  piston,  in  its  forward  stroke,  draws  the  valve  r  past  the 
port  n.  it  is  thrown  over  by  the  air  pressure ;  g,  through  r, 
now  communicates  with  i,  and  the  air  passes  from  the  rear  end  of 
the  piston  to  the  exhaust ;  at  the  same  time  the  three  passages 
h  are  connected  with  the  admission  inlets  of  compressed  air,  and 
the  piston  makes  its  return  stroke.  The  piston  is  thus  driven 
backwards  and  forwards,  striking  a  rapid  succession  of  blows, 
estimated  at  several  thousand  per  minute,  upon  the  back  end  of 
the  tool-holder  d,  and  as  fast  as  the  latter  is  knocked  forwards  it  is 
drawn  back  by  the  action  of  the  springs.  The  tool-holder  is  in  no 
way  connected  with  the  piston,  and  is  quite  free  to  turn  round. 

The  length  of  the  stroke  of  the  chisel  is  only  0*06  to  o'o8  inch 
(1*5  to  2  mm.)  As  the  annular  slide-valve  closes  the  ports  n  n  in 
passing,  the  air  acts  by  expansion  during  the  latter  part  of  the 
stroke.  The  air-pressure  employed  at  Mansfeld  is  60  Ibs.  per 
square  inch  (4  atm.) 

The  chisel  is  made  of  J-inch  round  steel  with  an  edge  |-  inch 
wide ;  it  is  inserted  in  the  •  strong  socket  of  the  tool-holder,  and 
the  miner  simply  holds  the  cylinder  so  that  the  chisel  presses 
against  the  shale  which  he  wishes  to  cut  away  (Fig.  205).  It  is 
said  that  a  man  can  undercut  or  "  hole  "  an  area  of  5  square  feet 
(o'5  sq.  m.)  per  hour.  Each  hewer  has  to  make  a  "  holing " 
about  10  feet  (3  m.)  long,  and  he  carries  it  in  to  a  depth  of  20 
inches  to  2  feet  from  the  face.  The  groove  or  "  holing  "  is  about 
5j  inches  (14  cm.)  high  at  the  face,  and  becomes  lower  and  lower 
as  it  goes  in. 

The  men  do  not  appear  to  suffer  in  any  way  from  the  vibrations 
of  the  machine,  which  weighs  only  10  Ibs.  (4*5  kil.)  including  the 
chisel. 

(2)  Travelling  Rock  Drills  and  Jumpers.— A  groove  may 
be  made  by  boring  a  succession  of  holes  immediately  touching 
each  other,  or  separated  by  small  partitions  which  are  broken 
down  afterwards  by  a  flat  bit  (broach).  Most  of  the  rock  drill 
companies  supply  special  quarry-bars  or  frames,  upon  which  an 
ordinary  boring  machine  can  be  mounted  and  made  to  travel, 
.and  thus  cut  a  groove  along  any  required  line. 

With  the  Ingersoll  bar-channeller  *  a  cutter  is  sometimes  used 

*  Eng.  Min.  Jour.,  vol.  xlix.  (1890),  p.  62. 


OF  THE 


202  OKE  AND  STONE-MINING. 

made  of  three  chisels  placed  side  by  side,  with  their  edges  arranged 
like  the  three  strokes  of  the  letter  N,  in  the  place  of  an  ordinary 
borer.  As  the  carrying  frame  can  be  inclined,  the  groove  can 
be  cut  at  an  angle. 

The  Wardwell  *  stone  channelling  and  quarrying  machine  may 
be  regarded  as  a  mechanical  jumper,  cutting  a  vertical  groove. 
It  is  a  portable  6  h.-p.  engine  with  boiler,  moving  upon  rails,, 
which  is  made  to  lift  a  set  of  boring  chisels  or  cutters  consisting 
of  five  bars  of  square  steel,  clamped  together  in  a  line.  The  edges, 
of  the  centre  and  outside  chisels  are  transverse,  whilst  the  other 
two  are  diagonal,  and  they  are  arranged  in  step  fashion.  Three 
cutters  only  act  at  a  time,  viz.  the  centre  cutter,  and  either  the 
two  in  front  or  behind  it,  according  as  the  machine  is  being 
moved  forwards  or  backwards.  "  The  machine  consumes  400  Ib, 
of  coal  a  day,  and  requires  the  services  of  three  men.  It  will  cut 
from  75  to  150  square  feet  of  channel  in  marble,  and  150  to  400- 
square  feet  of  limestone  and  sandstone  in  a  day,  which  is 
equivalent  to  the  work  of  50  men." 

The  Cleveland  Stone  Company,  Ohio,  employs  no  less  than 
thirty-nine  of  these  machines  in  quarrying  sandstone,  with  the- 
modification  of  having  only  three  cutters  instead  of  five. 

The  channelling  machines  of  the  Ingersoll  and  Sullivan  Com- 
panies running  upon  rails,  either  with  or  without  a  boiler,  will 
cut  vertical  or  inclined  grooves. 

(3)  Circular  Saws. — In  alphabetical  order  the  following  may 
be  named :  Crump  and  Brereton,  Gillott  and  Copley,  Walker,. 
Winstanley. 

Crump  and  Brereton s  f  machine  is  used  for  quarrying  stone  in 
the  United  States.  It  will  cut  long  vertical  grooves  30  inches 
deep  and  about  |  inch  wide. 

It  consists  of  a  frame  on  wheels,  moving  upon  rails,  which 
carries  a  small  vertical  boiler,  steam-engine,  circular  saw  about 
5  feet  in  diameter,  and  the  gearing  necessary  for  driving  it  and 
causing  the  whole  carriage  to  advance  as  the  cut  is  made.  The 
saw  is  a  thin  circular  steel  blade,  about  f  inch  thick  with  slots  all 
round  the  edge  into  which  the  teeth  are  inserted.  They  are 
arranged  so  that  they  divide  the  narrow  cut  of  |  inch  into  3  parts, 
each  tooth  taking  \  inch.  The  teeth  are  sharpened  by  grinding. 
The  saw  is  driven  from  the  periphery  by  a  toothed  wheel  on  each 
side,  the  teeth  of  which  gear  into  two  circular  sets  of  holes  cut 
near  the  circumference  of  the  saw.  It  is  said  that  while  making 
a  cut  30  inches  deep  in  slate,  it  will  progress  at  the  rate  of 
4  inches  a  minute. 

The  Gillott  and  Copley^,  machine  (Fig.  215)  has  been  specially 

*  Eng.  Miu.  Jour.,  vol.  xlvii.  (1889),  p.  500. 
f  Engineering,  vol.  xli.  (1886),  pp.  [54,  272. 

+  G.  B.  Walker,  "  Coal-getting  by  Machinery,''  Proc.  Fed.  Inst.  Min. 
vol.  i.  (1890),  p.  128. 


BREAKING  GROUND.  203 

designed  for  cutting  a  more  or  less  horizontal  groove,  under  or  in 
a  seam  of  coal,  but  it  can  also  be  applied  to  seams  of  other  com- 
paratively soft  minerals.  It  is  a  cast-steel  or  malleable  iron  wheel 
4  feet  in  diameter,  armed  with  removable  teeth,  which  are  alter- 
nately double  and  single.  The  groove  which  is  cut  is  rather  more 
than  3  inches  wide,  and  is  big  enough  to  allow  the  bracket  sup- 
porting the  saw  to  enter  it.  Consequently,  a  cut  can  be  made 
nearly  as  deep  as  the  diameter  of  the  saw. 

Just  inside  the  circumference  there  is  a  circular  rack  into 
which  gears  a  bevel  pinion  driven  by  two  compressed  air  engines 
with  cylinders  9  inches  in  diameter  and  having  a  9-inch  stroke. 
The  saw  makes  about  30  revolutions  a  minute.  The  two  engines 
are  upon  the  carriage  which  supports  the  saw.  The  carriage  runs 
upon  rails  set  at  a  gauge  of  i  foot  yj  inches,  and  it  draws  itself 

FIG.  215. 


along  by  a  wire  rope,  which  has  one  end  fixed  at  some  convenient 
point  of  the  working  face,  and  the  other  coiled  upon  a  drum 
attached  to  the  carriage.  The  drum  is  made  to  revolve  by  a 
pawl  and  ratchet-wheel  worked  by  the  engines,  and  there  are 
means  of  regulating  the  number  of  teeth  taken  by  the  pawl, 
and  in  this  way  the  advance  of  the  machine. 

Two  men  are  required  for  working  the  machine ;  the  man 
in  front  lays  down  the  rails  and  sleepers,  which  are  taken 
up  and  passed  to  him  by  the  man  in  the  rear  as  soon  as  the 
machine  has  gone  over  them.  The  whole  machine  is  only  i  foot 
9  inches  above  the  rails  ;  its  width,  exclusive  of  the  saw,  is  3  feet 
3  inches,  and  total  length  9  feet ;  it  weighs  altogether  24 
cwt.  The  makers  state  that  it  will  undercut  to  a  depth  of 
39  inches  in  hard  coal  or  shale  at  the  average  rate  of  12  yards 
per  hour,  with  an  air  pressure  of  about  30  Ibs.  per  square  inch. 
The  saw  cuts  from  back  to  front,  and  therefore  clears  out  the 
chippings  that  it  makes. 

The  Rigg  and  Meiklejohn  machine,  which  is  in  operation  in 
Scotland,  is  a  circular  saw  of  somewhat  similar  construction. 

The  cutting  of  a  preliminary  groove  in  some  of  the  Cheshire 
salt  mines  has  long  been  done  by  Walkers  circular  saw  (Fig.  216). 

An  improved  form  of  the  Winstanley  saw  is  doing  good  work  at 


204  ORE  AND  STONE-MINING. 

the  Blanzy  collieries.  It  is  a  circular  saw  5  feet  (1.50  m.)  in 
diameter,  with  28  removable  cutters,  all  of  one  shape,  upon  its 
circumference.  The  cutters  are  arranged  in  fours,  so  that  four  of 

FIG.  216. 


them  cover  the  whole  width  of  the  holing,  which  is  3  inches 
(7-6  cm.)  high.  Two  small  compressed  air  engines,  inside  the 
waggon  which  carries  the  saw,  drive  a  horizontal  pinion,  which 
gears  into  the  spaces  between  the  cutters  ;  in  fact,  the  saw  is  a  cog 
wheel  with  a  cutter  inserted  into  each  tooth.  The  depth  of  the 
holing  is  4  feet.  The  total  weight  of  the  machine  is  35  cwt. 
(iSookil.) 

(4)  Endless  chain  with  cutters  attached. — Baird's  machine* 
which   is  used  both  for  coal  and  ironstone,  is  of  this  type.     A 
carriage  moving  on  rails  supports  two  cylinders  worked  by  com- 
pressed air,  and  these  set  in  motion  an  endless  chain  with  cutters, 
which  revolves  round  two  pulleys,  one  at  each  end  of  a  jib  or  arm. 
The  jib  can  be  made  to  extend  under  the  seam  for  a  distance 
varying  from  2  feet   9  inches  to  5  feet,  and  the  groove  which  is 
cut  is  only  2^  inches  high. 

It  is  stated  that  a  machine  will  make  an  undercut  2  feet  9 
inches  deep  by  100  yards  long  in  8  or  10  hours. 

(5)  Wire  Saw. — The  most  novel  method  of  cutting  stone  is 
one  which  has  been  used  at  marble  quarries  in  Belgium  and  else- 
where, and  is  called  by  the  inventor  the  Helicoidal  Saw  System. 

It  consists  in  sawing  grooves  by  an  endless  cord,  composed  of 
three  steel  wires  twisted  together,  which  travels  on  the  rock,  and 
is  supplied  with  sand  and  water.  The  sand  is  drawn  along  by 
the  spaces  between  the  wires,  and  will  cut  even  very  hard  stone. 
At  present  only  vertical  grooves  have  been  cut ;  the  first  process 
consists  in  sinking  two  pits  for  receiving  the  pulleys  which  guide 
the  cord  in  making  its  cut,  and  which  have  to  be  lowered  as  the 
cut  is  deepened.  The  pits  are  bored  2  feet  4  inches  (700  mm.)  in 
diameter  by  cylinders  of  sheet-iron,  with  the  lower  and  cutting 
edge  made  of  sheet-steel.  The  cylinder  is  made  to  rotate  at  the 

*  Walker,  ibid. 


BREAKING  GROUND. 


205 


rate  of  100  to  180  revolutions  a  minute  by  a  vertical  axis  set  in 
motion  by  a  horizontal  pulley  at  the  top,  driven  by  a  wire  rope, 
whilst  sand  and  water  are  fed  in  to  the  cutting  edge.  As  the 
annular  groove  is  cut  deeper  and  deeper,  the  cylinder  is  gradually 
lowered  by  a  little  winch  and  two  wire  ropes.  The  cylinders  now 
in  use  are  constructed  so  as  to  cut  to  a  depth  of  10  feet  9  inches 
(3-30  m.).  When  this  cut  has  been  made,  a  core  remains,  which 
can  easily  be  broken  off  at  the  bottom  and  lifted  out.  In  the 
case  of  marble  the  core  can  be  utilised  and  sold  as  a  column.  If 
there  is  a  demand  for  smaller  columns,  boring  cylinders  of  less 
diameter  are  used,  and  two  or  four  holes  are  bored  side  by  side. 
After  the  removal  of  the  columns  the  thin  intervening  partitions 
of  rock  are  broken  down,  and  space  enough  is  afforded  for  the  in- 
troduction of  a  pulley  and  a  frame. 

Two  of  these  pulley-pits  are  prepared  at  the  two  extremities  of 
the  line  along  which  it  is  desired  to  make  a  saw-cut,  which  may 
be  50  feet  or  more  in  length,  if  required,  and  the  carriers  are  then 
inserted.  The  carrier,  made  of  channel  iron,  supports  two 
pulleys,  each  2  feet  in  diameter ;  one  is  fixed  at  the  top,  whilst 
the  second  is  so  arranged  that  it  can  be  lowered  by  a  large  screw. 

The  cord  for  sawing  in  the  quarry  is  about  J  inch  (6  mm.)  in 
diameter,  made  up  of  three  wires  of  mild  steel,  twisted  together  so 


FIG.  217. 


as  to  form  a  strand.  It  is  driven  at  the  rate  of  13  feet  (4  m.)  pel- 
minute,  and  will  deepen  the  cut  in  marble  at  the  rate  of  3  to  4 
inches  or  more  per  hour.  The  friction  of  the  spiral  wires  on  the- 
pulleys  and  rock  causes  the  cord  to  revolve  a  little  as  it  is  carried 
forwards,  and  all  parts  of  it  are  thus  equally  worn.  When  it  is 
so  much  worn  that  it  no  longer  presents  spiral  spaces  which  will 


206  ORE  AND  STONE-MINING. 

hold  sand,  it  lias  to  be  changed.  If  it  breaks  while  in  use,  it  can 
very  easily  be  spliced. 

Fig.  217  represents  the  arrangement  adopted  at  the  Traigneaux* 
Quarry,  near  Philippeville,  Belgium.  A  B  C  D  E  F  is  the  wire 
cord  travelling  in  the  direction  shown  by  the  arrows ;  H  and  G 
are  the  two  pits  which  have  been  bored  to  hold  the  pulley-frames. 
When  the  cutting  process  began,  the  wire  cord  would  have  been 
running  along  the  line  I  J  ;  the  groove  is  gradually  deepened 
until  at  last  it  reaches  the  line  K  L. 

When  suitable  vertical  cuts  have  been  made,  the  block  is 
severed  horizontally  by  means  of  wedges. 

(6)  Revolving  Bar  with  Cutters. —  Under  this  head  may  be 
classed  the  Bower,  Lechner,  and  Legg  machines,  all  of  which  have 
been  designed  for  holing  coal. 

Bower's  machine  consists  of  a  bar  3^  feet  long,  armed  with 
steel  teeth,  which  is  made  to  revolve  at  the  rate  of  600  to  800 
revolutions  a  minute  by  an  electric  motor.  The  bar  rapidly  cuts 
away  a  groove  as  the  motor  is  made  to  travel  along  the  rails ;  the 
groove  is  5  inches  high  in  front,  and  3  at  the  back.f 

In  the  Lechner  and  Legg\  machines  the  cutting  bar  lies  parallel 
to  the  line  of  the  face,  and  not  at  right  angles  to  it,  as  in  Bower's 
coal-cutter. 

V.  Machines  for  Excavating  Complete  Tunnels  — Hither- 
to machines  of  this  kind  have  been  little  used.  Three  may  be 
mentioned — viz.,  the  Beaumont,  Brunton,  and  Stanley  tunnellers. 

The  Beaumont  machine  has  received  a  good  deal  of  notice, 
owing  to  its  having  been  employed  in  the  Channel  Tunnel.  It 
consists  of  a  very  heavy  horizontal  iron  shaft,  which  is  made  to 
revolve  by  compressed  air  engines.  The  shaft  carries  a  cross-head 
armed  with  teeth,  which  cut  away  the  whole  face  by  a  series  of 
concentric  grooves.  The  chips  are  made  to  fall  on  to  an  endless 
chain  with  backets,  and  are  thus  conveyed  to  a  waggon  behind 
the  machine,  so  that  no  interruption  of  the  work  takes  place  for 
loading.  The  machine  travels  forward  in  a  cradle  which  fits  the 
bottom  of  the  circular  tunnel,  and  when  the  limit  of  advance  is 
reached,  the  ma.chine  is  lifted  up  by  screw-jacks,  and  the  cradle 
is  once  more  brought  under  it,  so  that  a  new  cut  can  be  begun. 

Like  the  Beaumont  machine,  Brunton 's  tunneller  §  excavates  a 
circular  drift  by  chipping  away  the  whole  face,  but  in  this  case 
the  work  is  done  by  steel-cutting  discs  about  10  to  20  inches  in 
diameter,  and  from  ^  inch  to  i  inch  thick.  As  yet  it  has  been 
little  used. 

*  Copied  from  a  pamphlet  published  by  the  Socltti  anonyme  Internationale 
dufilheliqoidal.  Brussels,  1888. 

t  G.  B.  Walker,  "  Coal-getting  by  Machinery,"  Proc.  Fed.  Jnst.  Min.  Eng., 
vol.  i.  p.  129. 

%  Eny.  Min.  Jour.,  vol.  xlvi.  (June  1888),  p.  399. 

§  Jour.  Soc.  Arts,  vol.  xxii.  (1873-74),  p.  404. 


BREAKING  GROUND. 


207 


Stanley's  tumieller  (Fig.  218),  on  the  other  hand,  is  a  compara- 
tively new  machine  already  doing  good  work  in  driving  headings 
in  coal.  It  consists  in  the  main  of  a  strong  central  shaft,  which 
carries  a  cross-head  with  two  projecting  arms,  At  the  end  of  each 
arm  are  three  steel  teeth  or  cutters.  The  central  shaft  is  made  to 
revolve  by  a  pair  of  small  vertical  compressed  air-engines,  and  the 
teeth  cut  away  an  annular  groove  3  to  4^  inches  wide.  The  chips 

FIG.  218. 


are  brought  out  by  scrapers  attached  to  the  arms  which  carry  the 
teeth.  The  advance  of  the  cutters  is  caused  by  the  forward 
movement  of  the  main  central  shaft ;  this  is  screwed  outside,  and 
works  in  a  nut  attached  to  the  frame.  The  rate  of  advance 
is  therefore  determined  by  the  pitch  of  this  screw  and  the  speed 
with  which  it  is  made  to  turn  round. 

After  boring  the  annular  groove  to  the  depth  of  a  foot  or  so, 
large  lumps  of  the  central  core  break  off,  and  the  machine  is 
stopped  to  get  them  out.  Work  is  then  resumed  till  the  arms 
have  penetrated  to  their  full  length.  The  machine  is  stopped, 
the  remaining  part  of  the  core  is  wedged  out  and  cleared  away, 
and  now  the  frame  is  run  forward  and  fixed  for  another  cut. 
The  rate  of  progress  when  working  in  coal  is  about  i  yard  per 
hour,  and  during  a  trial  of  24  hours  the  machine  cut  a  tunnel 
64  feet  6  inches  in  length.  The  diameter  of  the  headings  or 
tunnels  is  5  feet.  A  machine  for  working  in  harder  rock  with  a 
slower  cut  is  being  tried. 

Stanley  has  also  made  a  modification  of  his  tunneller  in  which 
the  whole  of  the  face  is  cut  into  little  pieces ;  the  chips  are  carried 
off  by  an  Archimedean  screw  and  delivered  into  a  waggon  at  the 
back. 

MODES  OP  USING-  HOLES  FOR  BREAKING 
GROUND. — After  holes  have  been  bored,  either  by  hand  or  by 
machinery,  a  force  of  some  kind  has  to  be  applied  inside  them  in 
order  to  produce  a  rending  action.  The  commonest  method  is  to 
employ  an  explosive,  but  the  treatment  of  the  subject  would  not 


LIBR/, 


2o8  ORE  AND  STONE-MINING. 

be  complete  without  a  brief  mention  of  some  other  processes. 
Holes  may  receive  : — 

1.  Wedges. 

2.  Water. 

3.  Wooden  plugs. 

4.  Compressed  air  cartridges. 

5.  Hydraulic  cartridges. 

6.  Lime  cartridges. 

7.  Explosives. 

i.  Wedges. — When  a  hole  has  been  bored,  a  compound  wedge 
can  be  inserted  which  can  do  the  work  of  splitting  with  far 
greater  ease  than  a  single  wedge  driven  into  a  mere  crack  in  the 
rock.  The  combination  of  three  wedges  is  known  as  the  plug  and 
feathers,  a  flat  wedge,  the  plug,  being  inserted  between  the 
feathers,  which  have  the  outer  face  curved.  The  feathers  are 
placed  in  the  hole  and  the  plug  is  driven  down  between  them  with 
a  hammer  or  sledge. 

Varieties  of  this  simple  apparatus,  in  which  the  wedge  or  the 
feathers  are  moved  by  hydraulic  pressure  or  by  a  screw  worked 

FIG.  219. 


by  hand,  have  been  used  for  getting  down  coal.     Fig.  2 1 9  is  the 
Elliott  multiple  wedge  of  the  Hardy  Patent  Pick  Company. 

2.  Water. — In  cold  climates  the  expansion  of  water  in  freezing 
can  be  utilised  for  rending  rocks  in  open  quarries.     A  row  of  holes 
is  bored  in  the  line  along  which  it  is  wished  to  split  off  a  block  of 
stone,  the  holes  are  filled  with  water  and  well  stopped  with  wooden 
plugs ;  when  the  water  is  converted  into  ice,  the  block  splits  off. 

3.  Wooden  Plugs. — Dry  oaken  plugs  are  driven  into  holes  and 
then  watered.     The  wood  expands  and  causes  a  fracture. 

4.  Compressed  Air. — Air  compressed  to  about  400  Ib.  per 
square  inch  has  been  employed  experimentally  in  the  place  of  gun- 
powder for  breaking  down  coal. 

5.  Hydraulic   Cartridges. — Levet  proposes    to    use    a    flat 
metallic  tube  placed  in  a  borehole,  which  is  rammed  up  tightly. 
The  flat  metallic  cartridge  is  then  connected  with  an  hydraulic 
press,  and  as  soon  as  this  is  worked  the  cartridge  expands,  and 
the  coal  is  broken  off. 

6.  Lime  Cartridges. — This  plan  is  mentioned  with  the  two 
last,  not  because  it  is  employed  in  mines  at  the  present  time,  but 
simply  to  complete  the  series  of  methods  of  applying  a  rending 
force  in  boreholes. 

A   small  iron   pipe   is   first   placed  in  the  borehole,  which  is 
2 f  inches  in  diameter,  and  then  a  cartridge  of  compressed  lime 


BREAKING  GROUND.  209 

with  a  groove  to  fit  the  pipe  is  inserted.  The  hole  is  now  tamped 
up,  and  water  pumped  into  the  pipe,  saturating  the  charge. 
Great  heat  is  evolved,  some  of  the  water  is  converted  into 
steam,  the  lime  expands,  and  large  blocks  of  coal  are  broken  oft'. 

7.  Explosives. — Thirty  years  ago  gunpowder  was  practically 
the  only  substance  used  for  blasting  at  mines ;  but  nowadays  the 
number  of  explosives  is  great,  and  an  exact  classification  is 
necessary  before  they  can  be  conveniently  studied. 

With  the  permission  of  Colonel  Cundill,  R.A.,  I  borrow  the 
classification,  as  well  as  certain  details,  from  his  Dictionary  of 
Explosives.* 

1.  Gunpowder  ordinarily  so-called. 

2.  Nitrate  mixtures  other  than  gunpowder. 

3.  Chlorate  mixtures. 

4.  Nitro-compounds  containing  nitro-glycerine  ;  this  includes  the  great 

dynamite  class. 

5.  Nitro-compounds,  not  containing  nitro-glycerine  (gun-cotton,  &c.) 

6.  Explosives  in  which  picric  acid,  or  a  picrate,  is  a  main  constituent. 

7.  Explosives  of  the  Sprengel  type. 

8.  Miscellaneous  explosives. 

(i)  Gunpowder. — Though  gunpowder  has  lost  much  of  its 
former  importance,  owing  to  the  greater  strength  of  many  of  its 
younger  rivals,  it  is  still  largely  employed  for  several  reasons,  viz., 
its  relative  cheapness ;  its  slower  action,  which  renders  it  more 
suitable  for  blasting  in  certain  soft  rocks  and  for  producing  rents 
without  any  violent  smashing;  and  lastly,  its  freedom  from 
certain  dangers  which  cling  to  some  of  the  nitro-compounds. 

The  formula  commonly  given  for  gunpowder  is:  75  parts  of 
saltpetre,  15  of  carbon,  and  10  of  sulphur;  but  the  powder 
used  for  blasting  in  mines  usually  contains  less  saltpetre  than 
that  which  is  employed  for  sporting  or  military  purposes. 

The  following  is  an  analysis  of  mining  powder  by  Captain 
Nobel  and  Sir  F.  Abel  :— 

Per  cent. 
Saltpetre    .         .         .         .         .         •        r  6l'66 

Potassium  sulphate 0-12 

Potassium  chloride 0-14 

Sulphur 15-06 

Carbon I7'93 

Hydrogen  .         .         .         .         .         .         .0-66 

Oxygen      .         .         .        ...         .        .     2-23 

Ash 0-59 

Water i'6i 

100-00 

The  products  of  the  explosion  of  gunpowder,  according  to  the 
same  authors,f  are  by  weight : 

*  Dictionary  of  Explosives,  London,  1889,  p.  vii. 
t  "  On  Fired  Gunpowder,"  Phil.  Trans.  1880,  pp.  225,  278. 

o 


210 


ORE  AND  STONE-MINING. 


Curtis  &  Harvey's 
No.  6  Gunpowder. 

Mining 
Powder. 

Total  solid  products         .... 
Total  gaseous  products    .... 
Water      

57-74 
41-09 
1-17 

47-04 

51-35 
1-61 

100-00 

100-00 

The  solid  residue  of  the  mining  powder  consisted  mainly  of 
potassium  carbonate,  potassium  monosulphide,  and  sulphur. 

The  percentage  composition,  by  volume,  of  the  gas  produced 


was : 


Curtis  &  Harvey's 
No.  6  Gunpowder. 

Mining 
Powder. 

Carbonic  anhydride 
Carbonic  oxide     ... 
Nitrogen                                  f 
Sulphuretted  hydrogen 
Marsh  gas     .... 

50-22 

J-52 

2-08 
2-46 
3-26 

32-I5 
33-75 
19-03 

7-10 
2-73 

100-00 

100-00 

The  volume  (calculated  for  a  temperature  of  o°  C.  and  barometer 
760  mm.  of  mercury)  of  permanent  gases  generated  by  the  ex- 
plosion of  i  gramme  of  dry  powder  is  : 


Curtis  &  Harvey's  No.  6 
Mining      . 


.  241-0  cubic  centimetres. 
•  360-3      „ 


Mining  powder  is  usually  coarse-grained  and  highly-glazed,  but 
the  workmen  who  adhere  to  the  old  plan  of  firing  with  straws 
require  a  little  fine-grained  powder  for  filling  them.  In  quarry- 
ing and  mining  slate,  a  fine-grained  gunpowder  of  very  good 
quality  has  been  found  by  experience  to  answer  best  for  rending 
the  rock  evenly  without  smashing  it. 

Gunpowder  is  used  either  loose,  or  in  cartridges  made  by  the 
men  on  the  spot,  or  in  cartridges  supplied  to  them.  Gunpowder 
compressed  into  cylinders  of  diameters  suitable  for  bore-holes,  and 
provided  with  a  central  hole  for  the  insertion!  of  the  fuse,  has 
lately  been  brought  forward  with  some  success ;  but  it  has  the 
great  disadvantage,  shared  with  all  hard  cartridges,  of  not  fitting 
the  bore-hole  so  closely  as  a  pulverulent  or  plastic  explosive. 

(2)  Nitrate  Mixtures  other  than  Gunpowder. — As  nitrate 
of  soda  is  very  much  cheaper  than  nitrate  of  potash,  inventors  have 


BREAKING  GROUND.  211 

naturally  tried  it  as  a  substitute  for  the  most  expensive  in- 
gredient of  gunpowder.  The  drawback  of  such  explosives  is  that 
they  get  damp,  owing  to  the  deliquescence  of  the  nitrate  of  soda  ; 
and  some  of  the  so-called  waterproof  cases  have  been  insufficient 
in  the  humid  climate  of  Great  Britain  to  keep  out  the  moisture 
sufficiently. 

(3)  Chlorate  Mixtures. — Chlorate  of  potash  is  an  unstable 
salt,  very  sensitive  to  friction  and  percussion,  and  the  explosives 
made  from  it  are  so  dangerous  that  only  one,  aspkaline,  has  been 
licensed  in  Great  Britain.     It  was  so  light  and  bulky  that  it 
never  came  into  practical  use. 

Rack-a-rock  is  chlorate  of  potash  soaked  with  "  dead  oil,"  a 
dark  heavy  oil  consisting  chiefly  of  hydro-carbons,  and  derived 
from  coal  tar,  or  with  a  mixture  of  equal  volumes  of  dead-oil  and 
bisulphide  of  carbon,  or  with  dinitro-benzole.  The  cartridges  of 
compressed  chlorate  of  potash  are  dipped  in  the  liquid  when  re- 
quired for  use ;  the  two  ingredients,  when  separate,  are  not 
explosive. 

More  than  100  tons  of  this  explosive  were  used  in  the  great 
blast  for  removing  the  Hell  Gate  rocks  in  New  York  Harbour, 
besides  which  large  quantities  had  been  consumed  in  making  the 
underground  galleries.  The  variety  employed  at  Hell  Gate  con- 
sisted of  79  parts  of  finely -ground  chlorate  of  potash,  and  21  parts 
of  dinitro-benzole. 

(4)  Nitro-compounds  containing  Nitro-glycerine. — Miners 
are  deriving  immense  benefits  from  explosives  of  this  class  which 
includes  dynamite  and  its  congeners. 

Nitro-glycerine  or  glyceryl  nitrate  is  a  light  yellow  oily  liquid 
with  a  specific  gravity  of  1-6,  which  freezes  at  about  40°  F. 
(4°  C.),  and  explodes  when  heated  to  360°  F.  (180°  C.),  or  sub- 
jected to  a  shock. 

Its  chemical  composition  is  expressed  by  the  formula 
C3H5(N03)3,  and  it  is  prepared  by  the  action  of  nitric  acid  upon 
glycerine.  It  is  extremely  sensitive  to  shocks,  and  under  the 
action  of  a  fulminating  cap  it  explodes  with  great  violence.  It  is 
less  sensitive  to  blows  and  detonation  when  frozen  than  in  the 
liquid  state. 

The  results  of  its  decomposition  when  perfectly  exploded  may 
be  represented  by  the  following  equation  : — 

2C3H5(N03)3  =  6C02  +  5H20  +  Nti  +  O. 

MM.  Sarrau  &  Yieille  *  have  communicated  to  the  Academy 
of  Sciences  the  results  of  their  researches  concerning  the  decom- 
position of  certain  explosives,  among  which  is  nitro-glycerine.  The 

*  "  Recherches  experiment  ales  sur  la  decomposition  de  quelques  explosifs 
en  vas  clos  ;  composition  des  gaz  formes:"  Comptes  fiendus,  1880,  pp.  1058 
1 1 12. 


UNIVERSITY 


212 


ORE  AND  STONE-MINING. 


following  table  shows,  in  litres,  the  volume  (at  o°  0.  and  760  mm. 
of  mercury)  of  each  of  the  gases  per  kilogramme  of  the  substance 
exploded  in  a  closed  vessel. 


Kind  of  Explosive. 

CO 

C02 

H 

N 

0 

C2H4 

H2S     Total 

Pure  gun-cotton    . 

234 

234 

1  66 

107 





741 

Gun-cotton  and  nitrate 

of  potash  (50  percent. 

each)  .... 

— 

171 

— 

109 

45 

— 

325 

Gun-cotton  (40  per  cent.) 

and    nitrate    of    am- 

monia (60  per  cent.)  . 

— 

184 

— 

211 

6 

— 

401 

Nitro-glycerine 

— 

295 

— 

147 

25 

— 

-       467 

Ordinary  blasting  pow- 

der    .... 

64 

150 

4 

65 

~ 

4 

17      304 

If,  however,  the  explosive  is  decomposed,  at  a  pressure  approach- 
ing that  of  the  atmosphere,  by  burning  or  imperfect  detonation, 
the  volumes  (again  at  o°  C.  and  760  mm.  of  mercury)  are  very 
different,  as  shown  below  : — 


Kind  of  Explosive. 

N02 

CO 

co2 

H 

N 

C2H4 

Total 

Pure  gun-cotton 

139 

237 

104 

45 

33 

7 

565 

Gun-cotton    and    nitrate    of 

potash  (50  per  cent,  of  each) 
Gun-cotton  (40  per  cent.  )  and 

71 

58 

57 

3 

7 

— 

I96 

nitrate  of  ammonia  (60  per 

122 

65 

103 

12 

112- 



414 

Nitro-glycerine 

218 

162 

58 

7 

6 

i 

452 

When  these  explosives  are  decomposed  in  this  way,  they  liberate 
nitric  oxide  and  carbonic  oxide,  and  the  analyses  of  MM.  Sarrau 
&  Vieille  confirm  the  practical  experience  of  miners,  who  complain 
greatly  of  noxious  fumes,  when,  owing  perhaps  to  a  bad  detonator, 
a  charge  of  dynamite  or  tonite  fails  to  explode  properly. 

Nitro-glycerine  was  at  first  used  alone,  and  was  fired  by  a 
small  cartridge  of  gunpowder  inserted  into  a  strong  paper  case 
containing  the  liquid  ;  this  method  soon  gave  way  to  the  fulminat- 
ing cap.  Numerous  accidents  happened  from  the  extreme  sensi- 
tiveness of  the  blasting  oil  to  percussion,  and  these  led  to  its  being 
given  up  in  most  countries.  Nobel,  who  had  introduced  nitro- 
glycerine, then  invented  a  method  of  using  the  explosive  with 
comparative  safety,  by  causing  it  to  be  absorbed  by  some  porous 
inexplosive  substance.  This  was  the  original  dynamite,  but  now 


BREAKING  GROUND.  213 

various  mixtures  of  nitro-glycerine  and  other  substances  are  made, 
and  we  may  place  them  all  in  the  great  dynamite  class. 

The  dynamites  may  conveniently  be  arranged  in  two  groups  : 

1.  Dynamites  with  an  inert  base  acting  merely  as  an  absorbent  for  the 
liquid  nitro-glycerine.     Example  :  Ordinary  dynamite. 

2.  Dynamites  with  an  active,  that  is  to  say,  an  explosive  or  combustible 
base.     This  explosive  or  combustible  base  may  be  charcoal,  gunpowder  or 
•other  nitrate  or  chlorate  mixtures,  gun-cotton  or  other  active  compounds. 
Examples: — Blasting  gelatine,   Gelatine    dynamite,   Gelignite,    Hercules 
powder,  Lithofracteur. 

Dynamite  was  made  originally  by  mixing  75  parts  by  weight  of 
thoroughly  purified  nitro-glycerine  with  25  parts  by  weight  of 
infusorial  earth,  known  as  Kieselguhr,  sufficiently  absorbent  in 
quality  when  mixed  in  the  above  proportions  to  prevent  exudation 
of  the  blasting  oil. 

The  British  license  for  making  dynamite  now  allows  the 
-addition  of  a  little  carbonate  of  ammonium  and  the  substitution  of 
carbonate  of  sodium,  sulphate  of  barium,  mica,  talc,  nitre,  for  a 
portion  of  the  Kieselguhr. 

At  ordinary  temperatures  dynamite  is  a  plastic  mass,  gene- 
rally somewhat  reddish  in  colour,  owing  to  a  little  ferruginous 
matter  in  the  infusorial  earth.  It  freezes  at  about  40°  F.  (4°  C.), 
and  when  once  frozen  remains  hard  at  higher  temperatures  than 
40°  F. 

In  the  frozen  state  it  is  less  sensitive  to  blows  and  detonation 
than  when  plastic,  but  it  is  more  susceptible  to  explosion  when 
set  on  fire.  At  some  seasons  in  certain  climates  it  has  to  be 
thawed  before  being  used.  The  natural  warmth  of  some  mines  is 
sufficient  to  soften  it  in  the  short  interval  between  the  time  it  is 
taken  below  ground  and  the  time  it  is  required  for  use ;  but  it  is 
often  necessary  to  resort  to  artificial  thawing.  A  special  pan  is 
supplied  by  the  makers  for  this  purpose.  It  consists  of  an  outer 
can  filled  with  hot  water,  which  encloses  a  receptacle  for  the 
explosive.  The  outer  can  is  surrounded  by  a  bag  of  painted 
canvas  filled  with  a  bad  conductor  of  heat,  so  that  the  water 
retains  its  warmth  for  a  long  time.  The  warming-pan  cannot  be 
put  on  to  a  fire  without  the  outer  covering  being  burnt ;  if  proper 
cans  are  supplied,  the  men  are  less  likely  to  try  the  dangerous 
experiments  of  warming  dynamite  in  an  old  meat-tin  over  a  candle, 
or  upon  a  shovel  at  the  smith's  forge,  methods  of  thawing  that 
are  not  unknown. 

The  trouble  of  thawing,  and  the  possibility  of  the  operation 
being  performed  in  a  dangerous  manner  by  the  miners,  are 
decided  disadvantages  to  dynamite  j  and  these  are  not  the  only 
ones.  Its  behaviour  with  water  is  a  source  of  danger.  If  left  in 
contact  with  water,  as  happens  sometimes  when  a  hole  misses  fire,  it 
disintegrates ;  the  heavy  oily  nitro-glycerine  separates,  and  finding 
its  way  into  cracks  is  liable  to  explode  with  violence  from  the  mere 


214  ORE  AND  STONE-MINING. 

concussion,  when  the  rock  is  struck  with  the  pick,  borer,  or  sledge.. 
A  fourth  drawback  lies  in  the  fact  that  the  whole  of  the  charge 
does  not  always  go  off ;  portions  may  remain  intact  and  then  explode 
unexpectedly  from  a  blow,  when  work  is  resumed  after  blasting. 
On  the  other  hand,  the  plasticity  of  dynamite  and  some  other 
nitro-glycerine  explosives  is  a  decided  benefit,  because  the  charge 
can  be  pressed  down  so  as  to  fit  a  hole  which  is  not  perfectly 
cylindrical,  or  a  cartridge  can  be  squeezed  flat  and  inserted  into  a 
crack  without  boring  any  hole  at  all.  Of  course,  the  main  advan- 
tage of  dynamite  and  its  congeners  over  gunpowder  is  their 
enormous  strength. 

Atlas  Powder. — This  is  a  lignine  dynamite,  consisting  of  wood- 
pulp  or  sawdust,  nitrate  of  sodium  and  nitro-glycerine.  It  is 
manufactured  in  the  United  States. 

Masting  Gelatine. — This  powerful  and  favourite  explosive  is 
made  by  mixing  nitro-cotton  (nitro-cellulose  carefully  washed  and 
purified)  with  nitro-glycerine  heated  to  about  100°  F  (38°  C.) 
until  enough  nitro-cotton  has  been  dissolved  to  convert  the  nitro- 
glycerine into  a  jelly-like  mass.  The  blasting  gelatine  in  ordinary 
use  contains  93  to  95  per  cent,  of  nitro-glycerine,  the  remainder 
being  nitro-cotton.  In  the  plastic  state  it  is  less  sensitive  to  a 
shock  or  blow  than  dynamite,  but  when  frozen  the  reverse  is  the 
case.  One  great  advantage  which  it  possesses  over  ordinary 
dynamite  is  that  it  is  practically  unaffected  by  water.  That  it 
must  be  stronger  than  ordinary  dynamite  is  evident  at  first  sight, 
because  an  active  explosive  is  substituted  for  a  wholly  inert  sub- 
stance. But  there  is  the  additional  reason  that  the  two  explosives 
mutually  assist  each  other.  The  explosion  of  nitro-glycerine,  as 
we  have  seen,  liberates  free  oxygen ;  that  of  nitro-cotton  liberates 
carbonic  oxide.  In  other  words,  the  former  explosive  has  more 
oxygen  than  is  necessary  for  complete  combustion,  the  latter  less. 
The  excess  of  oxygen  of  the  nitro-glycerine  makes  up  for  the 
want  of  it  in  the  nitro-cotton. 

Gelatine  dynamite  is  a  mixture  of  80  per  cent,  of  blasting  gela- 
tine with  nitrate  of  potassium  and  wood  meal. 

Gelignite  is  a  similar  mixture  containing  only  60  per  cent,  of 
blasting  gelatine. 

Giant  powder  is  a  term  used  in  America  for  dynamite.  The 
Giant  powder  used  in  California  consists  of  nitro-glycerine,  nitrate 
of  sodium  and  wood-pulp  or  sawdust.  Like  Atlas  powder  it  is 
therefore  a  ligriine  dynamite.  Several  varieties  are  made  con- 
taining from  20  to  80  per  cent,  of  nitro-glycerine. 

In  Hercules  powder,  also  an  American  explosive,  the  nitro 
glycerine  is  mixed  with  wood-pulp,  carbonate  of  magnesium,  and 
nitrate  of  sodium,  or  with  carbonate  of  magnesium,  chlorate  of 
potassium,  nitrate  of  potassium  and  white  sugar. 

Lithofracteur  is  no  longer  seen  in  England,  though  regularly 
used  in  the  Australian  Colonies. 


BREAKING  GROUND.  215 

It  may  be  looked  upon  as  ordinary  dynamite  mixed  with  a 
crude  sort  of  gunpowder. 
One  analysis  gave  — 

Nitro-glycerine         .....  52 

Kieselguhr        ......  30 

Powdered  coal  ......  12 

Nitrate  of  soda         .....  4 

Sulphur    .......  2 

Other  varieties  of  the  explosive  contain  such  ingredients  as 
charcoal,  bran,  sawdust,  nitrate  of  barium,  bicarbonate  of  sodium. 

(5)  Nitro-  compounds  not  containing  Nitro-glycerine.  — 
The  explosives  of  this  class  now  in  practical  use  are  made  from 
the  nitro-compounds  :  —  Nitro-cellulose,  Nitro-benzole,  or  Nitro- 
naphthalene. 

Nitro-cellulose  or  gun-cotton  is  prepared  by  the  action  of  a 
mixture  of  nitric  and  sulphuric  acids  upon  cotton.  A  mixture  of 
certain  definite  proportions  and  strength  is  used  in  order  to  secure 
the  special  product  required  as  a  blasting  agent.  It  lacks  the 
plasticity  of  dynamite  and  blasting  gelatine,  but  it  can  claim  the 
advantage  of  never  requiring  to  be  thawed.  It  is  made  up  into 
cylindrical  cartridges  to  suit  bore-holes  of  various  diameters,  with 
a  central  hole  for  the  insertion  of  the  fulminating  cap  or 
detonator.  Per  se,  gun-cotton  is  not  largely  used  in  mining. 
When  gun-cotton  explodes  properly  its  decomposition  may  be 
represented  by  the  following  equation  :  — 

2(C6H702)3N03)  =  9CO  +  3CQ+  ;H2O  +  N6. 


One  of  the  products  of  the  explosion  is  the  poisonous  carbonic 
oxide.  This  disadvantage  can  be  counteracted  by  the  addition  of 
a  nitrate,  and  tonite  is  an  explosive  produced  in  this  manner.  It 
is  a  mixture  of  gun-cotton  and  nitrate  of  barium,  sold  in  cylin- 
drical cartridges  coated  with  paraffin  to  keep  out  the  moisture. 
By  some  miners  it  is  preferred  t  D  dynamite  for  reasons  of  safety. 
It  does  not  freeze,  and  there  is  no  danger  of  exudation  of  an  ex- 
plosive oil,  when  a  charge  which  has  missed  fire  has  to  be  left  in 
a  wet  hole. 

Ammonite  is  a  mixture  of  nitrate  of  ammonium  with  mono- 
nitro-naphthalene.  Bdlite  is  a  mixture  of  nitrate  of  ammonium 
with  di-  or  tri-nitro-  benzole.  Roburite  is  essentially  a  mixture 
of  nitrate  of  ammonium  with  chlorinated  di-nitro-benzole.  It  is 
a  yellowish-brown  powder,  and  is  sold  in  cartridges.  Sometimes 
there  is  also  some  chloro-nitro-  naphthalene  as  an  ingredient. 
It  is  largely  used  in  coal  mining.  Securite  is  an  explosive  of 
similar  composition. 

(6)  Picric  Acid  and  Picrates.  —  No  explosives  of  this  class 
are  in  use  in  mines  or  quarries. 

(7)  Explosives  of  the  Sprengel  Type.  —  Dr.  Sprengel  pre- 


2l6 


ORE  AND  STONE-MINING. 


pares  explosives  on  the  spot  immediately  before  use,  from 
substances  which  by  themselves  are  not  explosive.  He  mixes  a 
combustible  body  with  a  highly  oxidised  body  in  such  proportions 
that  the  supply  of  oxygen  shall  produce  complete  combustion,  and 
he  fires  the  mixture  with  a  detonating  cap. 

Thus,  for  instance,  nitro-benzole  compounds  are  mixed  with 
nitrates  of  ammonium,  potassium,  or  sodium.  These  could  be 
placed  in  Class  5.  Rack-a-rock,  mentioned  in  Class  3,  is  an 
explosive  of  the  Sprengel  type. 

Dr.  Sprengel's  method  cannot  be  employed  in  this  country, 
because  it  is  not  legal  to  manufacture  explosives,  even  by  mere 
admixture  of  the  ingredients,  except  in  duly  licensed  factories. 

(8)  Miscellaneous  Explosives. — Fulminate  of  mercury,  used 
in  making  detonators,  is  the  only  explosive  of  this  class  which 
requires  any  mention.  Detonators  are  small  copper  cylinders, 
closed  at  one  end,  containing  a  small  quantity  of  fulminate  of 
mercury.  They  are  made  of  various  sizes  to  suit  different 
explosives. 

Strength. — The  strength  of  explosives  may  be  compared 
by  firing  them  in  holes  bored  in  leaden  cylinders,  and  then 


FIG.  220. 


FIG.  221. 


FIG.  222. 


FIG.  223. 


FIG.  224. 


FIG.  225. 


ScAUtS 


measuring  the  size  of  the  cavity  produced  in  each  case.  Fig. 
220  shows  a  hole  6  inches  deep  bored  in  a  strong  block  of 
lead.  The  firing  of  20  grammes  (nj  drachms)  of  gunpowder  in 
such  a  hole  enlarged  it  but  slightly  (Fig.  221),  whilst  the  dila- 
tation caused  in  similar  holes  by  firing  like  charges  of  dynamite 


BREAKING  GROUND.  217 

(Fig.  222),  gelignite  (Fig.  223),  gelatine  dynamite  (Fig.  224),  and 
blasting  gelatine  (Fig.  225)  illustrates  the  enormously  greater 
power  of  these  nitro-glycerine  explosives. 

Charging  and  Firing. — The  commonest  method  of  firing  a 
charge  is  by  means  of  the  safety  fuse,  a  cord  T3^-  to  J  inch  in 
diameter,  containing  a  core  of  gunpowder  introduced  during  the 
process  of  manufacture.  Upwards  of  forty  or  fifty  varieties  are 
made  to  suit  the  requirements  of  the  miner  and  the  quarryman. 
The  cord  is  somewhat  guarded  against  damp  by  tar,  and,  if  more 
protection  is  needed,  the  covering  is  increased  in  thickness,  and 
a  layer  of  varnish  is  interposed.  For  wet  ground  the  outer 
part  of  the  fuse  is  formed  by  one  or  two  spiral  coils  of  tape 
or  by  gutta-percha.  For  blasting  under  water,  the  coat  of  gutta- 
percha  is  often  strengthened  against  injury  by  tape,  or  is  doubled 
or  trebled.  If  still  more  care  is  necessary  in  order  to  secure  an 
absolutely  impervious  envelope,  the  fuse  is  made  of  lead  tube,  either 
bare  or  protected  in  various  ways*  Special  fuses  are  supplied  for 
export  to  warm  countries.  Fuse  is  usually  sold  in  coils  24  feet  in 
length,  but  it  can  be  obtained  in  longer  coils  for  special  purposes. 
One  or  several  white  or  coloured  threads  run  down  the  centre 
of  the  core  of  powder,  and  serve  as  trade-marks  by  which  the 
goods  of  different  manufacturers  can  be  recognised.  They  are 
sometimes  impregnated  with  nitrate  of  potassium,  with  the  view 
of  carrying  the  fire  along  in  case  there  should  accidentally  be  a 
slight  interruption  in  the  continuity  of  the  core.  Safety-fuse 
burns  at  the  rate  of  about  two  or  three  feet  per  minute,  so  it  is 
easy  for  the  miner  to  secure  ample  time  for  retreat  by  taking  a 
sufficient  length.  Sometimes  a  fuse  hangs  fire,  and  many  are  the 
accidents  that  have  been  caused  by  returning  too  speedily  to  a 
hole  on  the  supposition  that  the  fuse  had  failed  altogether. 
"  Hang- fires  "  may  be  due  to  damp,  imperfection  in  manufacture, 
or  injuries  before  or  after  the  fuse  was  put  in  the  hole.  Colonel 
Majendie  has  shown  that  oil  exercises  a  very  retarding  effect  upon 
the  rate  of  burning  of  safety-fuse. 

In  blasting  with  gunpowder  in  the  ordinary  way,  the  charge  is 
put  in  either  loose  or  enclosed  in  a  paper  bag,  and  it  is  pressed 
down  to  the  bottom  of  the  hole  with  a  wooden  stick,  whilst  a 
piece  of  fuse  also  is  inserted,  extending  from  the  charge  well 
beyond  the  hole.  If  the  powder  is  loose,  the  miner  carefully 
wipes  down  the  sides  of  the  hole  with  a  wet  swab-stick,  or  with  a 
wisp  of  hay  twisted  round  the  scraper,  in  order  to  remove  any 
loose  grains  adhering  to  the  fuse  or  the  sides  of  the  hole,  and  then 
presses  in  a  wad  of  dry  hay,  moss,  or  paper.  A  little  fine  tamping, 
often  the  dust  from  boring  a  dry  hole,  is  now  thrown  in  and 
rammed  down  with  the  wooden  charging-stick,  and  the  same 
process  is  repeated  until  an  inch  or  two  of  tamping  has  been 
introduced.  The  metal  tamping-bar  is  now  brought  into  opera- 
tion, and  the  hole  completely  filled.  If  the  hole  is  pointing 


^X 

f 

I  TJ 


OFTHF 

TJNT 


218 


ORE  AND  STONE-MINING. 


upwards,  the  stuff  for  tamping  has  to  be  done  up  in  little  paper 
cartridges,  which  are  pushed  up  and  then  tightly  rammed. 

The  hole  is  now  ready  for  firing.  As  a  rule  the  safety-fuse  is 
not  ignited  directly.  In  open  quarries  a  piece  of  touch-paper  is 
attached  to  the  end  of  the  fuse,  so  that  in  burning  it  will 
eventually  light  the  gunpowder.  In  mines  a  candle-end  (snuff)  is 
fixed  under  the  fuse  by  a  piece  of  clay ;  it  is  lighted  to  see  that 
everything  is  all  right  and  that  it  will  burn  properly,  and  then 
blown  out.  The  miner  puts  his  tools  out  of  the  way  of  clanger, 
and  after  shouting  "  Fire  "  several  times,  sets  light  to  the  candle 
and  beats  a  retreat  to  some  place  where  there  is  no  fear  of  being 
struck  by  the  blast,  and  whence  he  can  warn  persons  who  might 
otherwise  walk  into  danger  unawares.  The  candle  burns  through 
the  covering  of  the  fuse,  the  fire  reaches  the  core,  and  is  soon, 
conveyed  to  the  charge,  which  explodes  and  does  the  necessary 
work. 

The  old  plan  of  firing,  which  is  still  in  use  in  many  places, 
consists  in  inserting  the  needle  into  the  charge  and  then  tamping 
up  the  hole.  Care  is  taken  to  draw  out  the  needle  a  little  as  the 
tamping  proceeds,  so  as  to  prevent  too  much  force  being  required 
for  its  final  withdrawal.  The  small  hole  left  in  this  way  serves 
for  the  insertion  of  a  straw,  rush,  or  series  of  small  quills  filled 


FIG.  226. 


FIG.  227. 


FIG.  22 


with  fine  powder,  which,  like  the  fuse,  reaches  from  the  outside 
to  the  charge.  A  short  squib,  which  shoots  a  stream  of  sparks 
down  the  needle-hole,  is  also  used  occasionally.  The  straw  or 
squib  is  lighted  by  some  kind  of  slow  match,  made  either  by 
dipping  a  cotton  strand  in  melted  sulphur,  or  soaking  a  piece  of 
paper  or  a  wooden  lucif er  in  the  tallow  of  a  candle ;  touch-paper 
is  also  used  for  the  purpose. 

Nitro-glycerine  and  nitro-cotton  explosives  are  fired  by  the 
detonation  of  a  strong  cap,  which  is  a  small  copper  cylinder  closed 
at  one  end,  partly  filled  with  a  mixture  of  fulminate  of  mercury 
and  chlorate  of  potassium.  The  amount  of  the  fulminate  required 
depends  upon  the  explosive,  and  the  makers  supply  detonators  of 
different  degrees  of  strength. 


BREAKING  GROUND. 


219 


The  treble-strength  detonators  of  the  Nobel  Company,  supplied 
for  firing  dynamite  (Fig.  226),  contain  0*54  gramme  of  the 
mixture ;  whilst  the  quintuple  detonators,  for  blasting  gelatine 
(Fig.  227),  have  o'S  gramme,  and  the  sextuple  detonators  i 
gramme. 

As  full  instructions  for  use  are  issued  with  every  packet  of  the 
nitro-glycerine  explosives,  it  is  not  necessary  to  repeat  them  here. 

Fig.  228  shows  a  hole  charged  with  two  cartridges  of  blasting 
gelatine,  a  primer  (i.e.,  a  small  cartridge)  and  cap,  and  afterwards 
filled  up  with  water  as  tamping.  The  fuse  is  turned  back  and 
fixed  by  a  lump  of  clay,  and  the  little  candle-end  is  placed  in 
position  for  lighting. 

PfeifFer  and  Wiehenkel  *  propose  to  make  blasting  with  high 
explosives  safer  and  more  eificient  by  interposing  a  column  of 
water  between  the  charge  and  the  primer.  The  concussion  pro- 
duced by  firing  a  primer  at  the  mouth  of  the  hole  is  communicated 
by  the  water  to  the  charge,  and  is  said  to  be  sufficient  to  cause  it 
to  explode.  Of  course  the  explosive  used  should  be  one  not  liable 
to  set  free  nitro-glycerine  when  in  contact  with  water,  as  happens 
with  dynamite. 

In  a  few  mines  where  the  straw  still  lingers  in  place  of  the 
fuse,  the  detonator  is  squeezed  on,  and  then  gently  inserted  into 
the  hole  left  by  the  withdrawal  of  the  needle. 

The  workman  employed  in  getting  slate  frequently  desires  to 
produce  a  rent  without  smashing  the  rock.  He  fills  the  hole, 


FIG.  229. 


FIG.  230. 


possibly  10  or  12  feet  deep,  almost  up  to  the  top,  with  a  small- 
grained  gunpowder,  and  after  ramming  in  a  wad  of  dry  moss  and 
an  inch  of  tamping,  sets  light  to  the  fuse  in  the  usual  way. 
Provided  his  calculations  are  correct,  the  block  is  severed  off 
cleanly,  and  not  broken  up. 


German  Patent  Specification,  No.  67,793,  1893. 


220  ORE  AND  STONE-MINING. 

In  quarrying  sandstone,  Knox  *  has  found  it  advantageous  to 
leave  an  air-chamber  above  the  charge  of  gunpowder  in  the 
rifting  holes  (Fig.  229).  A  is  the  powder,  B  the  air-space,  and  C  the 
tamping  resting  upon  a  wad  of  hay,  grass,  oakum,  or  paper. 

For  the  purpose  of  firing  several  holes  simultaneously,  Messrs. 
Bickford,  Smith  &  Co.,  the  original  inventors  of  the  safety-fuse, 
have  brought  out  a  special  arrangement,  the  action  of  which  is 
rendered  plain  by  the  Fig.  230.  An  ordinary  fuse  is  fixed  into  a 
metal  case  called  the  igniter,  from  which  a  number  of  instantaneous 
fuses  convey  fire  to  as  many  separate  holes.  It  is  found  in  prac- 
tice that  this  fuse  answers  very  well. 

In  mines  where  the  atmosphere  may  be  inflammable  from  the 
presence  of  fire-damp,  the  burning  fuse  may  become  a  source 
of  danger,  and  a  special  igniter  has  been  devised  by  Messrs. 
Bickford,  Smith  &  Co.,  to  prevent  accidents  arising  from  this 
cause.  With  the  same  object  in  view,  frictional  exploders  have 
been  introduced,  which  ignite  the  charge  when  a  string  is  pulled  ; 
but  these  belong  more  especially  to  the  domain  of  coal-mining. 

Charges  may  be  readily  fired  singly  or  simultaneously  with  the 
aid  of  electricity,  either  of  high  or  low  tension.  Low- tension 
fuses  have  the  advantage  that  they  can  be  tested  with  a  weak 
current  and  a  galvanometer  before  use.  If  the  galvanometer  is 
not  deflected,  it  is  evident  that  the  fuse  is  defective. 

Fig.  231  shows  a  section  of  one  of  Brain's  high-tension  fuses.  A 
is  a  cylindrical  wooden  case  containing  a  paper  cartridge,  B,  with 

FIG.  231. 


an  electric  igniting  composition,  C,  at  the  bottom.  Two  copper 
wires,  D  D,  enclosed  in  gutta-percha,  E  E,  reach  down  to  the 
composition,  where  they  are  about  3T^  inch  apart.  A  copper  cap 
or  detonator,  G,  is  fixed  on  the  small  end  of  the  wooden  case. 
The  insulated  wires,  D  D,  are  long  enough  to  reach  beyond  the 
bore-hole.  The  ends  of  the  wires  are  scraped  bare,  and  one  wire 
of  the  first  hole  is  twisted  together  with  one  wire  of  the  next 
hole,  and  so  on,  and  finally  the  two  odd  wires  of  the  first  and  last 
hole  are  connected  to  the  two  wires  of  a  single  cable,  or  to  two 
separate  cables  extending  to  some  place  of  safety  to  which  the  men 
can  retreat.  Here  the  two  cable  ends  are  connected  by  binding 
screws  to  a  frictional  electrical  machine  or  a  dynamo  exploder. 
The  electricity  passes  through  the  wires,  making  a  spark  at 

*  See  p.  162. 


BREAKING  GROUND. 


221 


FIGS.  232  &  233. 


each  break,  and  so  firing  the  electric  igniting  composition.  The 
flame  flashes  through  the  hole,  H,  and  ignites  the  fulminating 
mercury,  the  detonation  of  which  causes  the  explosion  of  the 
dynamite,  blasting  gelatine,  or  tonite  surrounding  the  cap. 

The  fuses  supplied  by  Nobel's  Explosives  Company  are  some- 
what different.  Their  high-tension  fuse  (Fig  232)  consists  of  a 
copper  cap,  A,  into  which  has  been  pressed  a  mixture  of  fulminate 
of  mercury  and  chlorate  of  potash,  B  ; 
D  D  are  two  insulated  wires,  the  ter- 
minals of  which  are  embedded  in  Abel's 
flashing  composition,  F;  C  is  waterproof 
cement,  which  serves  to  hold  the  wires  in 
position  and  to  close  the  detonator.  The 
detonator  and  a  few  inches  of  the  wire 
are  dipped  in  shellac  varnish,  so  as  to 
make  certain  that  no  water  can  penetrate 
during  use.  The  current  of  electricity 
produces  a  spark  between  the  terminals, 
ignites  the  flashing  composition,  and  fires 
the  fulminate. 

The  low- tension  fuse  (Fig  233)  differs 
in  having  a  thin  bridge  of  platinum  wire, 
E,  soldered  across  the  terminals.  This 
bridge  is  embedded  in  a  composition,  F, 
consisting  of  gunpowder  and  gun-cotton. 

When  the  curreno  of  electricity  passes  through  the  bridge,  it 
heats  the  wires  to  redness,  igniting  the  composition  and  firing  the 
fulminate  as  before. 

Electric  firing  has  the  great  advantage  of  enabling  the  miner 
to  retire  to  a  perfectly  safe  place  before  attempting  to  explode  the 
charge.  This  is  important  in  sinking  shafts,  where  the  means  of 
escape  are  less  easy  than  in  levels.  A  second  advantage  is  the 
absence  of  danger  from  a  "  hang-fire,"  an  occasional  source  of 
accident  with  the  ordinary  safety-fuse.  On  the  other  hand,  in  the 
case  of  simultaneous  blasting,  it  is  impossible  to  be  sure  whether 
all  the  holes  have  gone  off  properly,  and  electrical  firing  was  given 
up  in  driving  a  level  in  Saxony,*  because  unexploded  dynamite 
cartridges  were  so  frequently  found  among  the  rubbish  after 
blasting. 

DRIVING  AND  SINKING. — We  now  come  to  the  appli- 
cation of  the  hand  and  machine  tools  in  driving  levels  and 
sinking  shafts. 

A  level  or  drift  is  a  more  or  less  horizontal  passage  or  tunnel, 
whilst  a  shaft  is  a  vertical  or  inclined  pit. 

In  driving  a  level  by  hand  labour  in  hard  ground,  the  first 


*  Dannenberg,  Jalirb.  f.  d.  Berg-  und  Huttenwesen  im  K.  Sachsen  auf 
das  Jahr  1890,  p.  37. 


222 


ORE  AND  STONE-MINING. 


thing  the  miner  has  to  do  is  to  "  take  out  a  cut,"  i.e.,  blast  out  a 
preliminary  opening  in  the  "  end  "  or  "  forebreast."  The  position 
of  this  first  hole  is  determined  by  the  joints,  or  natural  planes 
of  division,  which  the  miner  studies  carefully  so  as  to  obtain  the 
greatest  advantage  from  them. 

Thus  Fig  234  shows  a  case  in  which,  owing  to  joints,  it  was 
advisable  to  begin  with  hole  No.  i,  and  then  bore  and 
blast  2,  3,  and  4,  one  after  the  other.  The  miner,  as  a  rule, 
does  not  plan  the  position  of  any  hole  until  the  previous  one  has 
done  its  work  ;  in  fact,  he  regulates  the  position  and  depth  of 
each  hole  according  to  the  particular  circumstances  of  the  case. 

In  many  of  the  drivages  at  the  Festiniog  slate  mines  there  is 
a  well-marked  inclined  plane  of  separation,  known  as  the  "  clay 
slant,"  along  which  the  level  is  carried.  The  first  holes  are 
directed  towards  this  "  slant,"  and  most  of  them  are  bored  up- 
wards; in  this  manner  wedge-shaped  pieces  of  slate  are  easily 
blasted  out,  and  subsequent  holes  are  bored  so  as  to  increase  the 


FIG.  234. 


FIG.  235. 


of   this  opening  until  the   whole  face   of    the    "  end "    has 
been  taken  away. 

Though  a  vein  and  its  walls  may  be  hard,  there  is  occasionally 
a  soft  layer  of  clay  (D  D,  D  D,  Fig.  235)  along  one  wall  (dig, 
Cornwall;  gouge,  U.S.).  The  miner  works  this  away  with  the 
pick,  and,  after  having  excavated  the  groove  as  deep  as  possible, 
blasts  down  the  lode  by  side-holes,  and  so  pushes  the  level  for- 
ward. 

At  St.  Just,  in  Cornwall,  a  narrow  groove  is  worked  out  by 
a  flat  chisel  called  a  peeker. 

In  sinking  a  shaft  a  similar  method  of  proceeding  is  adopted. 
A  little  pit  (sink)  is  blasted  out  in  the  most  convenient  part, 
and  the  excavation  is  widened  to  the  full  size  by  a  succession 
of  blasts,  each  hole  being  planned  according  to  circumstances 
This  series  of  operations  is  repeated,  and  the  shaft  is  gradually 
deepened. 

Where  boring  machinery  is  employed,  less  attention  and  some- 
times no  attention  is  paid  to  natural  joints,  because,  when  once 


BREAKING  GROUND. 


223 


the  drill  is  in  its  place,  it  is  very  little  trouble  to  bore  a  few 
more  holes,  and  the  work  can  be  carried  on  according  to  a 
system  which  is  certain  of  effecting  the  desired  result. 

A  common   mode    of    driving   in   hard   ground    is   shown  in 
Figs.  236  and  237.     Four  centre  holes  are  bored  about  a  foot 


FIG.  236. 


FIG.  237. 


FIG.  238. 


apart  at  first,  but  converging  till  at  a  depth  of  3  feet  they  are 
within  6  inches  or  less  of  each  other. 

Other  holes  are  then  bored  around  them  until  the  end  is 
pierced  by  twenty  or  thirty  holes  in  all.  The  four  centre  holes 
are  charged  and  fired  simultaneously,  either  by  electricity  or 
by  Bickford's  instantaneous  fuse,  and  the  result  is  the  removal 
of  a  large  core  of  rock.  The  holes  round  this  preliminary 
opening  are  then  charged  and  fired,  generally  in  volleys  of  several 
holes  at  a  time,  and  the  level  is  thus  carried  forward  a  dis- 
tance of  3  feet.  If  large  holes  are  bored, 
and  if  the  ground  is  more  favourable, 
fewer  will  be  required. 

The  Halkyn  Drainage  Tunnel  (Flint- 
shire) is  being  driven  (7  feet  high  by 
7  feet  wide)  in  limestone  by  fourteen 
holes  for  each  advance ;  they  are  started 
with  a  3^-inch  bit,  and  finished  with  a 
2\ -inch  bit.  The  holes  are  placed  as 
shown  (Fig.  238),  and  are  bored  to  a  depth 
of  about  3  feet  9  inches  each.  They  are 
charged  with  dynamite,  25  Ibs.  being 
used  for  the  fourteen  holes,  and  then  blasted  in  four  volleys  : — 

ist  volley: — Nos.  i,  2,  3,  and  4  together,  which  take  out  the 
central  core. 

2nd  volley : — The  side  holes,  5,  6,  7,  8,  are  fired. 

3rd  volley : — The  top  holes,  9,  10,  n,  are  fired,  the  fuses  being 
arranged  so  that  No.  10  goes  off  before  Nos.  9 
and  ii. 

4th  volley: — The  bottom  holes,  12,  13,  14,  the  fuses  being 
arranged  so  that  No.  13  goes  off  before  Nos.  12 
and  14. 


'*,            5 

r 

7CD 

Jc:o«                   ~  "  "    * 

•  o:> 

^«         g 

? 

224 


ORE  AND  STONE-MINING. 


FIG.  239. 


Koughly  speaking,  it  takes  five  hours  to  bore  the  fourteen 
holes,  and  five  hours  more  to  charge  and  blast  them,  and  clear 
away  the  rubbish. 

Some  engineers  direct  the  four  centre  holes  so  that  they 
meet  at  the  apex  of  an  acute  pyramid,  and,  after  all  have  been 
charged  with  dynamite,  only  one  receives  a  primer  and  cap, 
because  the  shock  of  the  explosion  of  this  charge  is  sufficient  to 
fire  the  other  three  adjacent  charges  simultaneously. 

The  preliminary  opening  is  not  necessarily  made  in  the  centre 
of  a  level.  Sometimes  it  is  blasted  out  in  the  bottom  or  on  one 
side  where  there  are  natural  joints  to  favour  one  of  these  methods ; 
but  when  the  rock  is  uniform  it  is  best  made  in  the  centre,  for 
there  the  blasts  can  have  the  freest  play. 

At  Bex,  in  Switzerland,  where  water  power  is  abundant,  a  con- 
siderable saving  in  cost  has  been  effected  by  cutting  a  preliminary 
groove  in  the  centre  line  of  the  level  by  a  bosseyeuse. 

Seven  holes,  each  3^  inches  (8  cm.)  in  diameter,  are  bored  2 
inches  (5  cm.)  apart  in  a  straight  line, 
and  the  borer  is  then  replaced  by  a 
tool  which  breaks  down  the  partitions. 
A  groove  2  feet  10  inches  (86  cm.) 
long  and  3  J  inch  (8  cm.)  wide  is  thus 
formed,  and  after  the  bosseyeuse  has 
been  removed,  holes  1-2  inches  (3  cm.) 
in  diameter  are  bored  around  by  a 
Ferroux  drill  as  shown  in  the  diagram, 
Fig.  239. 

The  holes  A,  B,  C,  D,  E,  F,  G,  are 
blasted  at  one  time,  but  the  fuses  of 
A  and  B  are  cut  shorter  than  the 
others,  so  that  they  go  off  first.  The 
result  of  this  volley  is  the  produc- 
tion of  a  large  opening,  and  then  the 
firing  of  hole  H,  and  subsequently  of 
the  outside  holes,  completes  the  level  for  a  length  of  4  feet 
(1-20  m.).* 

In  driving  with  the  Ferroux  drill  in  the  ordinary 
way,  blasting  out  a  central  core,  with  dynamite, 
the  cost  per  metre  of  level  driven  was  .  .  Fr. 
By  using  the  bosseyeuse  to  make  a  central  groove, 
and  then  the  Ferroux  drill  for  the  remaining 
holes,  the  cost  per  metre  was  only  .  .  .  Fr.  39 


73     40 


40 


Saving  effected  by  the  use  of  the  bosseyeuse    .  Fr.  34     oo 

The  saving  therefore  is  as  much  as  46  per  cent. ;  but  in  this  case 
the  extra  water  power  required  is  costing  nothiog. 

*  Eosset,  Notice  sur  les  salines  de  Bex,  Bex,  1888,  p.  21. 


BREAKING  GROUND. 


225 


In  sinking  shafts  by  boring  machines,  operations  are  con- 
ducted much  in  the  same  way  as  in  levels,  save  of  course  that  the 
holes  are  directed  downwards. 

Figs.  240  and  241  are  a  plan  and  a  section  of  a  shaft  which  was 
sunk  at  the  Foxdale  mines  in  the  Isle  of  Man.  About  forty-five 
holes  were  bored  in  the  bottom  of  the  shaft  before  the  drills  were 
removed.  Two  of  the  holes  (A  and  B),  and  occasionally  four,  were 


FIG.  240. 


FIG.  241. 


.-•-— - 13  rr  6  i; -•-___„£ 


bored  only  4  feet  deep,  and  were  blasted  with  ordinary  fuse.  They 
served  simply  to  smash  up  and  weaken  the  core ;  then  the  six 
holes  nearest  the  centre,  which  were  8  feet  deep,  were  blasted 
all  together  with  Bickford's  instantaneous  fuse,  and  the  result 
was  the  removal  of  a  large  core,  leaving  a  deep  sink.  The  re- 
maining holes  were  fired  in  volleys  of  four  at  a  time  in  the 
ordinary  way.  In  this  manner  the  shaft,  which  was  in  hard 
granite,  was  deepened  at  the  rate  of  3^  or  4  fathoms  a  month. 
Tonite  wras  the  explosive  used. 

FIRE-SETTING. — Though  hard  ground  is  almost  invariably 
nowadays  attacked  by  boring  and  blasting,  the  very  ancient  pro- 
cess of  fire-setting  is  not  quite  obsolete.  The  effect  of  a  fire  is  to 
make  a  rock  split  and  crack,  and  render  it  easily  removable  by 
the  pick  or  by  wedges. 

In  1876  I  saw  a  level  in  course  of  being  driven  in  the  Kongsberg 
silver  mine,  Norway,  through  crystalline  schists,  by  this  method. 
A  fire  of  logs  of  fir  was  made  in  the  end,  and  the  smoke  was 
conducted  away  to  one  of  the  shafts  by  an  oval  sheet-iron  pipe, 
2  feet  by  i  foot. 

It  took  eight  cords  of  wood  to  drive  i  fathom  of  level,  and  the 
rate  of  advance  was  9  fathoms  in  7  months.  The  fire  was  usually 
made  up  twice  in  every  24  hours.  In  another  part  of  the  mine 
an  adit  level  was  being  driven  at  the  rate  of  2  fathoms  a  month, 
with  a  consumption  of  15  to  18  cords  of  wood.  In  this  case  an 
arch  was  built  in  the  roof  of  the  level  to  form  a  passage  for  the 
smoke,  and  the  iron  pipe  was  used  near  the  end. 

In  driving  in  hard  rock  in  the  gold  mines  of  Korea,*  a  pile  of 

*  W.  J.  Pierce,  "Gold  Mining  and  Milling  in  Korea,"  Trans.  Am.  /wrf. 
M.  E.,  vol.  xviii.,  1890,  p.  363. 

P 


226  ORE  AND  STONE-MINING. 

wood  is  set  on  fire  near  the  face  of  the  tunnel,  and  allowed  to 
burn  for  24  hours.  The  place  is  then  allowed  to  cool  for  three  or 
four  days,  when  the  miners  return  and  break  down  the  loosened 
rock  with  hammer  and  gad.  Fire-setting  is  also  employed  in 
mining  jade  in  Burmah,*  and  in  quarrying  stone  in  India,  f  Lastly, 
the  Siberian  prospector  avails  himself  of  the  softening  action  of 
fire  for  sinking  small  trial  shafts  through  ice  and  frozen  ground 
in  search  of  auriferous  gravel. 

EXCAVATING  BY  WATER. — We  turn  naturally  from 
fire,  one  of  the  four  elements  of  the  ancients,  to  another,  water, 
as  a  means  of  breaking  ground. 

Water  can  be  applied  either  for  dissolving  the  rock  or  mineral, 
or  for  loosening  it  and  then  carrying  it  away. 

There  are  two  cases  in  which  water  may  act  as  a  solvent — viz., 
common  salt  and  copper.  It  is  used,  as  we  shall  see  in  speaking 
of  the  methods  of  working,  to  dissolve  out  salt  from  saliferous 
rocks,  and  it  can  also  be  employed  for  excavating  upwards  or 
downwards  in  rock-salt.  For  excavating  upwards  ("  putting  up 
a  rise"),  a  jet  of  water  is  made  to  play  upon  the  roof  of  a  level, 
and  means  are  taken  to  carry  off  the  brine  in  troughs  (launders) 
without  dissolving  away  the  floor.  For  sinking  from  one  level  to 
another,  a  bore-hole  is  first  put  down,  and  this  is  gradually 
widened  by  the  solvent  action  of  water. 

When  old  workings  containing  the  sulphides  of  copper  are  left 
exposed  to  the  action  of  air  and  the  percolation  of  rain  water, 
part  of  the  copper  becomes  converted  into  a  soluble  sulphate,  and 
water  pumped  up  from  the  mine  may  become  a  profitable  source 
of  the  metal.  This  is  the  case  at  Parys  mine  in  Anglesey. 

There  are  also  two  cases  in  which  water  is  made  to  act  as  a 
loosener  and  conveyer — viz.,  for  working  clay  and  gold. 

A  stream  of  water  is  turned  on  to  the  deposits  of  china  clay, 
and,  aided  by  work  with  a  pick,  it  carries  everything  to  settling 
pits.  The  most  important  application  of  water  is  the  process  of 
washing  away  thick  beds  of  auriferous  gravel,  known  as  hydraulic 
mining.  A  huge  jet  of  water  under  pressure  is  made  to  play 
against  the  bank  of  gravel,  undermine  it,  cause  it  to  fall,  and  so 
thoroughly  disintegrate  it  that  everything  save  the  largest 
boulders  is  carried  away  in  the  stream.  Full  details  of  these  pro- 
cesses will  be  given  in  Chapter  VI.  (Exploitation). 

*  Eng.  Min.  Journ.,  vol.  xlviii.,  1889,  p.  359. 
f  Ibid.,  p.  547. 


CHAPTER  Y. 
SUPPORTING    EXCAVATIONS. 

Yarious  kinds  of  timber  used  for  supports. — Preservation  of  timber  from 
dry  rot. — Tools. — Timbering  levels,  shafts,  and  working  places. — 
Masonry,  brickwork  and  concrete  for  levels  and  shafts. — Iron  and 
steel  supports  for  levels,  shafts,  and  working  places. — Special  pro- 
cesses for  sinking  through  watery  strata  :  boring,  compressed  air  and 
freezing  methods. 

EXCAVATIONS  made  in  hard  ground  will  frequently  stand  with- 
out any  props  whatever  for  an  unlimited  time,  but  the  miner 
has  generally  to  deal  with  rocks  which  sooner  or  later  give  way 
unless  supported.  Consequently  it  becomes  necessary  to  adopt 
means  of  securing  the  underground  passages  and  working  places, 
•either  during  the  process  of  excavation,  or  at  all  events  very 
soon  afterwards. 

The  methods  of  securing  mining  excavations  may  be  classified 
according  to  the  materials  used  for  the  protective  lining,  viz., 
timber,  masonry,  iron,  or  steel. 

TIMBER. — In  Europe,  varieties  of  the  following  kinds  of 
trees  are  those  most  frequently  employed  underground  :  Oak, 
larch,  pine,  fir,  and  acacia. 

The  oak  is  especially  adapted  for  mining  purposes  on  account 
of  its  strength  and  its  durability.  It  will  resist  alternate 
exposure  to  wet  and  dryness,  and  under  water  it  is  almost  im- 
perishable. In  England  we  have  two  principal  varieties,  Quercus 
robur  pedunculata  and  Quercus  robur  sessiliflora. 

The  conifers,  larch,  pine,  and  fir,  have  the  advantage  of 
furnishing  straight  timber,  of  even  grain,  comparatively  light, 
easily  worked,  having  few  branches,  and  less  expensive  than  oak. 

The  larch  (Abies  larix  or  Larix  Europcea,  D.  C.)  is  an  excellent 
mining  timber.  The  large  amount  of  resin  it  contains  seems  to 
act  as  a  preventive  against  decay.  It  is  tough  and  strong,  and 
lasts  a  long  time,  even  when  alternately  wet  and  dry. 

The  American  pitch  pine  (Pinus  rigida)  is  a  timber  largely 
imported  into  this  country  for  mining  purposes,  and  it  is  used 
not  only  for  securing  shafts  and  levels,  bufc  also  for  pump-rods, 
bridges,  sides  of  ladders,  &c.  It  is  remarkable  for  its  perfectly 
straight  growth  ;  it  is  hard,  highly  resinous,  and  very  durable. 


228  ORE  AND  STONE-MINING. 

The  Scotch  fir  (Pinus  sylvestris)  is  a  tree  that  furnishes  a  great 
deal  of  mining  timber.  The  British-grown  timber  is  largely 
used  for  props,  whilst  balks  imported  from  Norway  and  Sweden 
serve  for  heavy  work  in  many  mining  districts. 

The  spruce  fir  (Abies  excelsa)  is  not  a  timber  to  be  recom- 
mended for  mine  supports  where  durability  is  required. 

The  acacia  has  the  property  of  resisting  the  effects  of  bad  air 
and  high  temperatures  very  much  better  even  than  oak. 

Mr.  Fernow*  gives  the  following  list  of  the  various  kinds  of 
mining  timber  which  are  available  in  the  United  States,  each 
series  being  arranged  in  order  of  durability,  beginning  with  the 
trees  most  adapted  to  resist  decay. 

EASTERN  RANGE. 

Conifers. — Eed  cedar  (Juniperus  Virginiana,  L.) ;  White  cedar  ( Chamcecy- 
paris  sphceroidea,  Spach.)  ;  Arbor  vitas  (Thuya  occidentalis,  L.)  ;  Bald 
cypress  (Taxodium  distichum,  Rich);  Long-leaved  pine  ( Pinus  palustris, 
Miller)  ;  Red  pine  (Pinus  resinosa,  Ait.)  ;  Cuban  pine  (Pinus  Ciibensis, 
Griseb.)  ;  Short-leaved  pine  (Pinus  mitis,  Michx.). 

Broad-leaved  trees. — White  oak  (Quercus  alba,  L.) ;  Post  oak  (Quercus 
obtusiloba,  Michx.)  ;  Chestnut  oak  (Quercus prinus,  L.)  ;  Live  oak  (Quercus 
virens,  Ait.);  Basket  oak  (Quercus  Michauxii,  Nutt.)  ;  Burr  oak  (Quercus 
macrocarpa,  Michx.)  ;  Osage  orange  (Madura  aurantica,  Nutt. ) ;  Hardy 
catalpa  (Catalpa  speciosa,  Warder);  Black  locust  (Rdbinia  pseudacacia, 
L.) ;  Honey  locust  (Gleditschia  triacanthos,  L.);  Red  mulberry  (Morusrubra, 
L.);  Chestnut  (Castanea  vulgaris,  var.  Americana,  A.D.C.) 

ROCKY  MOUNTAIN  REGION. 

Red   cedar  (Juniperus    Virginiana,    L.)  ;     Pinyon    pine    (Pinus  edulis, 

Engelm.)  :  Foxtail  pine   (Pinus   Balfouriana,   Murray) ;   Douglas  spruce 

(Pseudotsuga  Douglasii,  Carr.);  Western  larch  (Larix  occidentalis,  Nutt.); 
Burr  oak  ( Quercus  macrocarpa,  Michx.) 

PACIFIC  SLOPE. 

Yew  (Taxus  brevifolia,  Nutt.);  Redwood  (/Sequoia  sempervirens,  End- 
licher);  Lawson's  cypress  (Chamcecyparis  Lawsoniana,  Parl.) ;  Canoe 
cedar  (Thuya  gigantea,  Nutt.);  Douglas  spruce  (Pseudotsuga  Douglasii, 
Carr.)  ;  Western  larch  (Larix  occidentalis,  Nutt.) ;  Live  oak  (Quercus 
chrysolepis,  Liebm.)  ;  Post  oak  (Quercus  Garryana,  Dougl.). 

The  Douglas  spruce,  or  Oregon  fir  or  pine,  is  not  only 
used  in  America,  but  also  exported  to  Australia.  It  is  a  very 
straight  wood,  of  even  grain ;  it  has  the  disadvantage  of  easily 
taking  fire. 

In  Australia,  the  native  woods  are  commonly  used  for  mining 
purposes,  and  among  them  different  species  of  Eucalyptus  are 
specially  prominent. 

The  Jarrah  (Eucalyptus  marginata)  is  a  native   of  Western 

*  "  The  Mining  Industry  in  its  Relations  to  Forestry,"  Trans.  Am.  Inst. 
M.E.,  vol.  xvii.,  1888,  p.  264. 


SUPPORTING  EXCAVATIONS.  229 

Australia.  It  gives  a  red,  heavy,  intensely  hard  wood,  which  is 
difficult  to  work  with  ordinary  tools.  It  resists  decay  in  a  re- 
markable manner,  in  fact  it  is  practically  indestructible ;  the  white 
ant  and  the  "  teredo  navalis  "  will  not  attack  it.  Up  to  the  present 
time  there  has  been  little  need  of  mining  timber  in  the  colony  of 
which  it  is  a  native ;  but  it  is  exported  to  South  Australia  and 
New  South  Wales,  and  used  for  shaft-frames  and  other  special 
purposes. 

The  grey  or  white  iron-bark  (Eucalyptus  crebra,  F.  v.  M.), 
and  the  red  or  black  iron-bark  (Eucalyptus  leucoxylon,  F.  v.  M.), 
both  give  hard,  heavy,  strong,  and  durable  timber,  and  are  among 
the  most  useful  of  the  forest  trees  in  Australia. 

Grey  box  (Eucalyptus  largiflorens)  is  a  hard,  tough,  durable 
wood  which  lasts  well  underground.  The  young  trees  supply 
much  prop  timber  in  certain  localities. 

Stringy  bark  (Eucalyptus  obliqua),  possesses  similar  good 
qualities  ;  and  it  is  imported  into  Australia  from  Tasmania  if 
the  supply  of  the  native-grown  timber  is  insufficient  or  less  easily 
•obtainable.  It  is  employed  as  sawn  timber,  or  split,  and  the 
small  trees  make  excellent  props. 

Among  other  species  of  Eucalyptus  may  be  mentioned  the 
slaty  gum  (E.  bicolor,  A.  Cunn.),  and  bloodwood,  (E.  corymbosa, 
,Sm.),  both  strong  and  durable  and  used  for  railway  sleepers. 

The  prickly  leaved  tea-tree  (Melaleuca  armillaris)  gives  a 
hard,  strong,  heavy  timber,  lasting  well  underground. 

New  Zealand  can  boast  of  the  magnificent  Kauri  pine 
•(Dammara  Australis),  a  slow-growing  tree,  some  living  examples 
being  estimated  to  be  2000  years  old.*  It  contains  a  fluid  resin 
which  oozes  out  from  every  part,  and  hardens  into  large  masses 
•of  opaque  gum.  It  is  light,  elastic,  even-grained  and  strong. 
."Besides  being  used  for  timbering  mines  in  New  Zealand,  it  is 
•exported  to  Australia  for  the  same  purpose. 

Matai  (Podocarpus  ferruginea),  a  reddish-brown,  moderately 
hard  wood,  Miro  (Podocarpus  spicata),  and  Rewarewa  (Knightia 
excelsa)  may  also  be  mentioned  among  the  New  Zealand  mining 
timbers. 

In  Japan  the  levels  are  sometimes  timbered  with  bamboo. 

Preservation  of  Timber. — Most  authorities  consider  that  the 
best  time  for  felling  timber  is  winter,,  when  the  wood  has  the  least 
amount  of  sap  in  it,  because  fermentation  of  the  sap  is  one  great 
cause  of  decay.  For  this  reason  also,  timber  should  be  seasoned 
before  it  is  used ;  that  is  to  say,  it  should  be  allowed  to  dry  gradually 
and  so  lose  the  sap  by  evaporation.  Fernowf  says  that  proper 
seasoning  is  more  important  than  the  time  of  felling.  As  regards 

*  Laslett,  Timber  and  Timber  Trees,  London,  1875,  P-  29^- 
t  Op.  cit.  and  "  Eelation  of  Kailroads  to  Forest  Supplies  and  Forestry." 
Bulletin  No.  I,  Forestry  Division,  Department  of  Agriculture,  U.S.A.    Wash- 
ington, 1887,  pp.  37  and  67. 


23o  ORE  AND  STONE-MINING. 

the  removal  of  the  bark  or  not,  there  is  a  difference  of  opinion, 
but  it  certainly  facilitates  the  seasoning ;  and  in  the  case  of  oak 
the  bark  may  be  taken  off  for  sale  by  the  owner  of  the  plantations, 
before  he  disposes  of  the  timber  to  the  miner.  On  the  whole  it 
seems  advisable  to  remove  the  bark,  and  for  two  reasons — ( i )  less 
liability  to  rot,  and  (2)  earlier  indications  of  incipient  crushing, 

When  stored  at  the  mine,  timber  is  best  preserved  under  cover, 
protected  from  wind  and  weather,  but  with  ample  access  of  air ; 
and  it  is  important  to  remove  all  decaying  wood,  whether  logs, 
chips,  or  sawdust,  and  destroy  it  by  fire,  so  as  to  prevent  the 
spread  of  the  contagion.  The  timber  should  lie  upon  supports 
and  not  directly  on  the  ground,  and  the  pieces  should  not  be 
placed  too  close  together. 

According  to  Laslett,*  "the  approximate  time  required  for 
seasoning  timber  under  cover,  and  protected  from  wind  and 
weather,  is  as  follows  : — 

Oak.  Fir. 

Pieces  16  to  12  inches  square  14  months.  7  months. 

„       12  to    8     „  „  10      ,,  5      „ 

8  to    4      „  „  6      „  3      „ 

Planks,  from  one-half  to  two-thirds  the  above  time  according 
to  thickness." 

Timber  is  often  found  to  decay  very  rapidly  in  some  mines,  or 
in  certain  parts  of  a  mine,  owing  to  the  spread  of  what  is  called 
dry  rot.  This  is  a  white  fungus  which  grows  over  the  timber, 
and  causes  the  woody  fibre  to  decompose  and  become  so  soft  and 
rotten  that  a  knife  or  pick  can  be  run  in  with  the  greatest  ease. 

Various  methods  of  preventing  dry  rot  have  been  tried  with 
more  or  less  success.  Good  ventilation  is  all-important,  for 
timber  is  found  to  become  affected  most  rapidly  in  places  where 
the  air  is  foul  or  stagnant.  Water  has  a  decided  preservative 
effect,  so  much  so  that  arrangements  are  sometimes  made  for 
causing  it  to  trickle  down  continuously  over  the  timber  in  a 
shaft,  or  to  form  a  spray  in  timbered  levels.  Probably  the  water 
acts  by  washing  oif  the  spores  of  the  fungus  as  fast  as  they  are 
deposited  upon  the  timber,  and  also  by  cleansing  the  atmosphere 
and  keeping  it  cool. 

Mine  timber  is  also  occasionally  treated  with  antiseptics,  such  as 
brine  (with  or  without  chloride  of  magnesium),  borax,  creosote, 
carbolineum,  coal-tar,  corrosive  sublimate,  chloride  of  zinc,  sul- 
phate of  zinc,  sulphate  of  copper  and  sulphate  of  iron  ;  but  far  less 
attention  has  been  given  to  this  subject  by  mining  than  by  civil 
engineers,  to  whom  the  duration  of  railway  sleepers  (ties,  U.S.A.) 
is  a  matter  of  much  importance. 

Treatment  with  a  metallic  salt  is  preferred  to  creosoting,  if 
the  timber  is  at  all  exposed  to  the  risk  of  catching  fire. 

*  Op.  dt.  p.  316. 


SUPPORTING  EXCAVATIONS.  231 

The  timber  is  treated  in  one  of  the  following  ways  : — 

(1)  Steeping. — The  timber  is  simply  placed  in  the  preservation  solution, 
and  allowed  to  absorb  what  it  can. 

(2)  Hydrostatic  Process. — The  preservative   solution    is  forced  in    by 
hydrostatic  pressure. 

(3)  Vacuum  Process.— The  timber  is  placed  in  boilers,   and  steam  is 
admitted ;  the  air  and  vapours  are  then  exhausted,  and  a  preservative 
turned  in  under  pressure. 

(4)  Painting,  i.e.,  application  with  a  brush. 

It  was  found  by  experiments  carried  on  at  Commentry  during 
a  long  series  of  years,  that  one  of  the  best  methods  was  soaking  the 
timber  for  twenty-four  hours  in  a  strong  solution  of  sulphate  of 
iron  (green  vitriol).  The  total  cost  was  only  Jd.  per  yard  of  prop, 
whilst  the  timber  lasted  eleven  times  as  long  as  when  this  simple 
treatment  was  omitted.  "  Carbolineum  "  is  a  patent  preparation 
laid  on  with  a  brush  like  paint,  which  is  well  spoken  of  by  the 
mining  officials  at  Saarbriicken.*  The  cost  of  two  coats  of  the 
preservative  material  on  a  prop  8  feet  long  by  10  inches  in 
diameter  (2*5  m.  by  25  cm.)  is  about  7^d. 

The  duration  of  a  prop,  or  other  piece  of  timber,  is  not  the 
only  point  to  be  considered  in  deciding  whether  it  is  worth  while 
paying  the  cost  of  some  preservative  treatment.  The  expense  of 
the  labour  in  the  renewal  of  unsound  timber,  such  as  the  cutting 
of  fresh  hitches,  must  not  be  overlooked. 

Tools. — Timber  is  used  in  various  forms — either  whole  and 
merely  sawn  into  lengths,  or  hewn  or  sawn  into  square  balks,  or 
sawn  in  half,  or  sawn  or  split  into  planks  of  different  thicknesses. 

The  tools  used  by  the  miner  for  shaping  the  timber  are  the 
saw  and  axe  ;  in  addition  he  requires  a  measuring  staff,  a  sledge 
or  a  wooden  mallet  for  driving  the  timber  into  its  place,  a  hammer 
and  "  moil "  for  chipping  out  recesses  or  niches  (hitches),  plumb 
line  and  level. 

The  saws  vary  in  different  countries.  In  Great  Britain  the 
timberman's  saw  is  the  ordinary  hand-saw  of  the  carpenter, 
though  a  cross-cut  saw  worked  by  two  men  is  used  for  cutting 
large  props  or  balks.  In  the  Hartz  the  timberman  uses  a  saw 
somewhat  resembling  our  cross-cut  saw  in  shape,  but  smaller  in 
size,  and  having  the  toothed  edge  curved,  whilst  in  Saxony  a 
frame  saw  is  preferred.  All  large  mines  have  a  circular  saw,  and 
some  are  provided  with  special  machines  for  cutting  the  joints  of 
supporting  frames. 

The  axe  varies  in  shape  more  according  to  the  fancy  of  the  user 
than  any  special  difference  in  the  purpose  for  which  it  is  used. 

The  moil  is  merely  a  pointed  steel  bar.  In  order  to  ascertain 
the  length  required  for  a  piece  of  timber  to  fit  a  given  place,  the 
timberman  uses  a  measuring  staff,  consisting  of  two  bars  of  wood 

*  Zeitschr.f.  B.-  Ht-  u.  S.-Wesent  vol.  xxxviii.,  1890,  p.  265. 


232 


ORE  AND  STONE-MINING. 


which  are  made  to  slide  upon  each  other,  and  then  fixed  in  any 
position  by  a  thumb-screw.  One  end  is  often  rounded  so  that  it 
may  reach  to  the  bottom  of  the  niche  (hitch)  which  has  been  cut 
in  the  rock.  The  plumb  line  and  level  need  no  description. 

The  principal  kinds  of  excavations  in  mines  are  levels,  shafts, 
and  ordinary  working  places.  These  will  be  taken  in  order,  and 
the  methods  of  securing  them  dealt  with  briefly. 

Levels. — Though  a  level  is  an  excavation  of  a  very  simple 
nature,  the  methods  of  timbering  it  vary  considerably,  because 
the  parts  requiring  support  may  either  be  the  roof  alone,  or  the 
roof  and  one  or  two  sides,  or  the  roof,  sides,  and  bottom. 

If  the  roof  only  is  weak,  as  is  the  case  with  a  soft  lode  between 
two  hard  walls,  a  cap  with  a  few  boards  resting  on  it  (Fig.  242) 

FIG.  242. 


is  sufficient  to  prevent  falls.  If  one  side  is  weak  the  cap  must 
be  supported  by  a  side  prop  or  leg  (Fig.  243),  and  very  often  by 
two  legs.  The  form  of  joint  between  cap  and  leg  are  numerous 
(Fig.  244),  depending  to  a  great  extent  on  the  nature  of  the 


FIG.  244. 


FIG.  245. 

A  B 


FIG.  246. 


u 


pressure,  whether  coming  upon  the  top  or  sides,  and  also  on  the 
shape  of  the  timber,  whether  round  or  square.  With  round 
timber  the  top  of  the  leg  may  be  hollowed  out  as  shown  in 
Fig.  245  A  ;  but  occasionally  the  joint  is  flat,  and  a  thick  nail 
or  nog  is  put  (Fig.  245  B)  to  prevent  the  effects  of  side  pressure, 


SUPPORTING  EXCAVATIONS. 


233 


or,    better,   a   piece  of  thick   plank   is    nailed   under    the    cap 
(Fig.  246). 

Where  the  floor  of  a  level  is  soft  and  .weak,  a  sole-piece  or  sill 
becomes  necessary,  and  if  the  sides  or  roof  are  likely  to  fall  in,  a 


FIG.  247. 


CAP 


FIG.  248. 


SOLE      PIECE. 


Horned  sets 


FIG.  249. 


lining  of    planks  or  poles  is  used  (Fig.   246). 
(Fig.  247)*  are  useful  in  loose  ground. 

Fig.  248  shows  the  special  system  adopted  on  the  Comstock  lodef 
for  some  very  heavy  ground.  The  outer  planks  (lagging}  are  put 
close  together,  and  the  method 
of  jointing  has  been  carefully  de- 
signed so  as  to  prevent  any  yield- 
ing under  the  enormous  pressure 
to  which  it  is  subjected.  These 
levels  are  6  feet  high  inside  the 
timber. 

As  an  instance  of  timbering  on 
a  much  larger  scale,  I  give  a  re- 
presentation  of    the  supports  at 
Rio  Tinto,  Spain  (Fig.  249  );  the 
height   of    the    level   from    the 
groundsill  (a)  to  the  cap  (c)  is  1 2 
feet  7  inches  (3*85  m.),  so  as  to 
allow  the  passage  of  locomotives. 

In  driving  levels  for  the  deep 
gold-bearing  gravels  in  the  Cari- 
boo district,  B.C.,|  spruce  fir   i   to  2  feet  in  diameter,  simply 
barked,  is  used  for  making  the  sets.     The  lagging  is  in  pieces 

*  Rep.  Insp.  Mines,  Victoria,  for  1873,  p.  7.     Melbourne,  1876. 
t  Hague,  ''Mining  Industry,"  United  States  Geological  Exploration  of  the 
Fortieth  Parallel,  vol.  iii.,  plate  iv.,  p.  113.     Washington,  1870. 
t  Dawson,  "General  Note  on  the  Mines  and  Minerals  of  Economic  Value 


GO > 


234 


ORE  AND  STONE-MINING. 


4  feet  long,  5  inches  wide,  and  2  inches  thick,  and  is  split  out  of  logs. 
The  ground  is  so  heavy  that  the  frames  (sets)  are  only  a  few  inches 
apart  in  some  places.  Where  the  ground  is  very  wet,  spruce  brush- 
wood is  placed  behind  the  lagging. 

In  the  Day  Dawn  mines  in  Queensland,*  the  gold  vein  some- 
times attains  a  width  of  60  feet ;  the  hanging  wall  is  not  strong, 
and  large  portions  of  the  lode  itself  are  apt  to  slip  away. 


^                        SCALE 

10                       5                      10 

15                   20 

25  FEET 

'IMETKE1    0123 

A            5            6 

7  METRES 

Though  the  levels  could  be  driven  without  difficulty,  it  was  found 
impossible,  with  the  ordinary  methods  of  timbering,  to  keep  them 
open  permanently  after  the  vein  had  been  worked  away,  and  the 
whole  pressure  of  the  heavy  ground  on  the  hanging  wall  had  to 
be  supported.  At  last  the  so-called  "  pigsty  "  method  was  tried, 
and  it  has  been  found  very  successful.  It  consists  in  piling  up 
logs  4  to  8  feet  long,  two  by  two,  crosswise,  and  so  building  a 
support  which  covers  a  comparatively  large  area. 

Figs.  250  and  251  represent  the  pigsty  timbering;  the  former  is 

of  British  Columbia,"  Geol.  Survey,  Canada.     Reprinted  from  Canadian 
Pacific  Railway  Report,  1877,  p.  8. 

*  This  description  and  the  figures  have  been  kindly  supplied  by  Mr. 
Joseph  Shakespear,  one  of  the  Government  Inspectors  of  Mines  in  Queens- 
land. 


SUPPORTING  EXCAVATIONS. 


235 


a  section  along  the  line  of  dip,  the  latter  along  the  line  of  strike. 
As  the  drivage  progresses,  strong  sills,  10  to  12  inches  in  diameter, 
are  laid  along  the  floor  of  the  level.  These  sills  may  be  as  much 
as  25  feet  in  length,  and  two  of  them  are  laid  under  each  row  of 
sties,  which  are  placed  about  6  or  8  ft.  apart  in  the  direction 
of  the  level.  The  number  across  the  level  depends  upon  the 
width  of  the  lode,  and  the  spaces  between  the  rows  of  pigsties 
form  the  roads  for  the  waggons.  The  cap-pieces  are  made  of 

FIG.  251. 


SCALE 


i  o 


25  FEET 


(METRE    0 


7  METRES 


timber  15  inches  in  diameter,  and  they  rest  upon  the  pigsties. 
Upon  the  cap-pieces  comes  a  row  of  poles,  which  support  the 
deads  when  the  lode  is  worked  away  above. 

Where  the  width  of  the  lode  is  not  too  great,  the  sills  are  dis 
pensed  with ;  the  ground  at  the  bottom  of  the  level  behind  the 
end  is  excavated,  and  the  pigsties  are  built  up  from  the  foot- 
wall.  Consequently,  when  the  lode  is  removed  by  the  workings 
below,  the  level  is  not  affected  because  the  timbering  is  supported 
from  the  undisturbed  footwall. 

When  sills  are  used  in  a  very  wide  lode,  pigsties  resting  upon 
the  footwall  are  built  up  whilst  the  ore  is  being  excavated,  and 
they  are  arranged  so  as  to  come  exactly  under  the  sills  and  carry 
their  weight. 

This  method  of  support  requires  a  great  deal  of  timber,  but 
it  has  the  advantage  that  the  small  logs  used  for  the  pigsties  are 
inexpensive  and  easily  handled,  compared  with  huge  balks 
required  with  the  other  systems. 


236 


ORE  AND  STONE-MINING. 


If  the  ground  is  loose  so  that  the  roof  or  sides,  or  both,  will  run 
in  unless  supported,  the  method  of  working  called  spilling,  spiling, 
or  poling  is  pursued.  It  consists  in  supporting  the  weak  parts  by 
boards  or  poles  in  advance  of  the  last  frame  set  up.  The  process 
may  be  described  as  pushing  out  a  protecting  shield  in  very 
narrow  sections,  one  at  a  time.  The  poles  or  boards  (laths)  are 
driven  forward  by  blows  from  a  sledge,  and  the  ground  is  then 
worked  away  with  the  pick  ;  this  removal  of  ground  enables  the 
laths  to  be  driven  in  further ;  the  pick  is  now  once  more  called 
into  requisition,  and  by  successive  small  advances  the  shield  of 
poles  or  boards  is  extended  a  distance  of  3  or  4  feet.  Fig.  252 
shows  one  of  the  advance  poles  partly  driven,  with  the  front  end 


FIG.  252. 


FIG.  253. 


resting  upon  a  set  of  timber ;  the  pole  behind  it  is  in  its  final 
position.  The  section,  Fig.  253,  explains  that  the  lower  set  of 
poles,  those  which  are  in  the  course  of  being  driven,  have  room 
enough  to  slide  on  top  of  the  cap,  owing  to  the  blocks  placed 
upon  it  being  slightly  thicker  than  their  diameter. 

In  running  ground  it  is  necessary  to  have  the  laths-  fitting 
closely  together,  and  the  working  face  must  also  be  supported  by 
breast-boards,  kept  in  place  by  little  struts  resting  against  the 
nearest  frame.  These  are  removed  and  advanced  one  by  one, 
after  the  laths  in  the  roof,  sides  and  bottom  have  been  driven 
beyond  them. 

In  a  few  instances  the  end  of  a  level  in  running  ground  has 
been  kept  up  by  covering  the  entire  working  face  with  wooden 
wedges ;  an  advance  was  gradually  effected  by  driving  them  in 
with  a  heavy  sledge.  The  sides  and  top  of  the  level  were  pro- 
tected by  laths  in  the  ordinary  way. 

Shafts. — The  timbering  required  for  shafts  varies  according  to 
the  nature  of  the  ground  and  the  size  of  the  excavation.  A  mere 
lining  of  planks  set  on  their  edges  (Fig.  254)  suffices  for  small 
shafts,  corner-pieces  being  nailed  on  so  as  to  keep  the  successive 
frames  together. 

The  usual  method  of  securing  shafts  is  by  sets  or  frames.  Each 
set  consists  of  four  pieces — two  longer  ones  called  wall 'plates,  and 


SUPPORTING  EXCAVATIONS. 


237 


two  shorter  ones  called  end-pieces.  They  are  joined  by  simply 
halving  the  timber  at  each  end,  as  shown  in  Fig.  255,  the  wall- 
plate  being  made  to  rest  upon  the  end-piece,  though  this  arrange- 
ment is  sometimes  reversed.  A  more  complicated  joint  (Fig.  256) 
is  often  preferred.  The  separate  frames  are  kept  apart  by  distance 


FIG.  254. 


FIG.  255. 


FIG.  256. 


pieces  (studdles,  Cornwall;  jogs,  Flintshire;  posts,  U.S.),  and 
loose  ground  is  prevented  from  falling  in  by  boards  or  poles 
outside.  The  length  of  the  distance  pieces  must  depend  upon 
the  solidity  of  the  ground.  If  the  ground  is  very  weak  they  are 
not  used  at  all,  and  the  successive  frames  are  put  in  touching  each 
other ;  in  loose  ground  near  the  surface  the  distance  between 
the  frames  may  be  18  inches,  for  instance,  and  then  increased 
gradually  to  4  or  5  feet  when  the  shaft  has  penetrated  into  harder 
strata, 

The  end-pieces  are  sometimes  made  long  enough  to  project  a 
foot  or  eighteen  inches  beyond  the  wall-plates,  and  rest  in  niches 
in  the  rock.  Another  plan  is  to  insert  bearers  at  regular  intervals — 
say  every  30  feet — under  the  end-pieces.  The  bearers  are  generally 
of  oak,  and  in  a  shaft  of  medium  size  pieces  1 2  inches  by  1 2 
inches  are  taken,  and  cut  four  or  five  feet  longer  than  the  end- 
pieces.  They  therefore  project  2  to  2  feet  6  inches  at  each  end 
into  solid  ground,  and  decidedly  add  to  the  security  of  the  timber 
lining. 

The  sides  of  the  shaft  are  further  prevented  from  falling  in  by 
planks  which  rest  against  the  wall-plates  and  the  end-pieces. 
During  the  process  of  sinking,  the  last  frames  are  kept  in  position 
by  strong  iron  clamps,  and  when  a  length  of  10  or  12  feet  has  been 
completed,  planks  (lashings  or  listings)  are  nailed  on  inside,  stretch- 
ing over  several  frames  and  so  binding  them  all  together. 

This  lining  of  a  shaft  may  be  regarded  as  a  very  long  box, 
with  strengthening  ribs  at  short  intervals.  As  shafts  are 
frequently  used  for  the  several  purposes  of  pumping,  hoisting,  and 
affording  means  of  ingress  and  egress  by  ladders,  it  becomes 
necessary  to  divide  them  into  compartments.  Pieces  of  timber 
parallel  to  the  end-pieces  (bunions  or  dividings)  are  fixed  across 
the  shaft,  and  serve  to  stay  the  wall-plates,  to  hold  the  guides  or 


238 


ORE  AND  STONE-MINING. 


conductors,  to  support  planks  (casing  boards},  which  are  nailed  to 
them  so  as  to  form  a  continuous  partition  or  brattice,  and  to 
assist  in  carrying  the  ladder  platforms. 

The  magnificent  timbering  of  some  of  the  shafts  on  the 
Comstock  lode  is  described  by  Mr.  James  D.  Hague*  as  follows  : — 

"  The  timbering  consists  of  framed  sets  or  cribs  of  square 
timber,  placed  horizontally  4  feet  apart,  and  separated  by  uprights 
or  posts  introduced  between  them.  Cross-timbers  for  the  par- 
titions between  the  compartments  form  a  part  of  every  set.  The 
whole  is  covered  on  the  outside  by  a  lagging  of  3 -inch  plank 
placed  vertically." 

Figs.  257, 258, and  259,  copied  from  Mr.  Hague's  plates,  illustrate 
this  method  of  timbering.  Fig.  257  is  a  plan  of  the  shaft.  "  S  S 

FIG.  257. 


.are  the  longitudinal  or  sill-timbers;  T T,  the  transverse  end 
timbers ;  r,  guide-rods  between  which  the  cage  moves ;  </,  gains 
cut  in  the  sill-timbers  to  receive  the  ends  of  the  posts.  The 
sheathing  or  lagging  is  seen  enclosing  the  whole  frame." 

Fig.  258  is  a  transverse  section  through  the  partition-timber 
(dividing)  P,  of  Fig.  257,   "between  the  pumping  compartment 


FIG.  258. 


FIG   259. 


and  the  adjoining  hoisting  compartment,  looking  towards  the 
latter.  In  this  figure,  G  G  are  the  posts;  S,  the  sill-timbers ; 
P,  the  partition-timbers,  the  ends  of  which  are  framed  with  short 
*  "  Mining  Industry,"  United  States  Geological  Exploration  of  tlw  Fortieth 
Parallel,  vol.  iii.  p.  103. 


SUPPORTING  EXCAVATIONS. 


239 


tenons  that  are  received  in  gains  cut  in  the  sill-timbers  and  the 
ends  of  the  posts ;  r,  guide  rod ;  I,  lagging  or  sheathing." 
Fig.  259  is  an  end  view  of  the  frame  shown  in  Fig.  257. 

"  The  single  piece  T  forms  the  end,  while  the  double  pieces  P, 
forming  the  partitions,  are  seen  beyond.  The  outer  timbers  of 
each  set — that  is,  the  two  sides  and  ends  of  the  main  frame — are 
14  inches  square;  the  posts,  ten  in  number,  four  at  the  corners 
and  two  at  each  end  of  the  partitions,  are  of  the  same  size.  The 
dividing-timbers  forming  the  partitions  are  1 2  inches  square." 

The  pigsty  system  of  supporting  ground  has  been  applied  to 
an  inclined  shaft  at  Day  Dawn*  Mine  in  Queensland,  in  which 
the  ordinary  system  of  frames  was  proving  inadequate.  In  this 
case  the  shaft  had  been  sunk  on  the  inclined  lode ;  the  ore  had 
been  removed  on  each  side  and  replaced  by  "  deads,"  and  the 
sides  and  roof  were  supported  by  ordinary  frames  and  laths.  The 
manager  took  out  a  strip  of  deads  on  each  side  of  the  shaft,  and 
as  soon  as  sufficient  room  had  been  made,  he  built  up  a  couple  of 
pigsties,  and  then  another  two,  and  so  on.  The  space  between 
them  served  as  a  passage  (winze)  for  winding-up  the  deads  as  the 
work  progressed  downwards.  The  ends  of  the  long  horizontal 
balks  of  iron-bark  timber  (caps)  stretching  across  the  shaft  were 
made  to  rest  upon  the  pigsties,  and  upon  them  were  placed  poles 
which  supported  the  roof  (hanging-wall).  Since  this  method  has 
been  adopted  there  has  been  no  trouble  with  the  shaft.  The 
subsidence  of  the  hanging- wall  has  been  going  on,  but  the  pigsties 

FIG.  260.  ' 


yield  to  the  movement  without  becoming  crippled  or  useless. 
Occasionally  a  cap  piece  breaks  in  the  middle,  in  spite  of  its  great 
size,  but  it  can  easily  be  renewed. 

As  an  example  of  another  large  shaft  may  be  mentioned  the  new 

*  MS.  information  kindly  supplied  by  Mr.  Joseph  Shakespear,  Govern- 
ment Inspector  of  Mines,  Queensland. 


240 


ORE  AND  STONE-MINING. 


sinking  at  the  Calumet  and  Hecla  mines*  (Fig.  260),  which  is  ex- 
pected to  strike  the  copper  bed  at  a  depth  of  3325  feet  from  the 
surface.  The  shaft  is  rectangular,  23  feet  by  13  feet  6  inches 
within  the  timber,  and  divided  into  six  equal  compartments,  7  feet 
by  6  feet  3  inches  within  the  timber.  A  and  B  (Fig.  260)  are  for 
receptacles  for  winding  rock,  G  and  D  for  cages  for  raising  and 
lowering  men,  timber,  &c. ;  E  forms  the  upcast  air-way,  and  F  is 
for  air-pipes,  &c.  The  frames  and  the  dividing-pieces  are  made 
of  southern  pine,  12  inches  by  12  inches,  and  the  whole  is  sur- 
rounded by  a  close  lagging  of  3-inch  plank. 

At  Clausthal  in  the  Hartz,  round  timber  is  generally  used,  and 
special  means  are  adopted  for  resisting  the  heavy  pressure  of  the 
ground  upon  the  wall-plates. 

In  Fig.  261  a  a  are  the  wall-plates,  made  of  timber  i  foot  in 

FIG.  261. 


(e) 

a  

f? 

(^ 

f  \ 

<  //'  e"                > 

if*  i 

•?       in'  i)" 

: 

6 

d 

rf 

j 

tf 

<5 

I 

g 

fel 

u 

diameter;    66,  the  end-pieces;  e  e,  the  studdles,  which  are  18 
inches  long. 

The  end-pieces  are  not  halved  as  in  Fig.  255,  but  are  slightly 
wedge-shaped,  so  as  to  preserve  their  whole  strength  for  prevent- 
ing the  wall-plates  from  being  squeezed  together.  However,  reli- 
ance is  mainly  placed  upon  frameworks  of  round  timber,  1 5  inches 
in  diameter,  placed  at  the  ends  and  near  the  middle  of  the  shaft, 
and  shown  in  elevation  in  Fig.  262.  Each  framework  consists  of 
two  pieces,  1 8  to  20  feet  long  (wall-posts,  c  c),  kept  apart  by  dia- 
gonal struts  (stempels  or  spur-timbers,  d,  d',  «/").  The  foot  of  the 
lowest  stempel  fits  into  a  hitch  cut  in  the  long  wall-post,  whilst  the 
head  is  merely  hollowed  out  to  suit  the  curvature  of  the  opposite 
wall-post.  All  the  other  stempels  are  cut  out  in  this  way  at  both 
ends,  and  when  the  bottom  stempel  has  been  put  in,  the  others 
are  very  speedily  fixed  one  above  the  other.  If  necessary,  a  strong 
bearer,  h,  is  put  in  from  time  to  time  under  the  wall-posts,  and 
projects  a  foot  or  18  inches  into  the  ground  on  each  side  of  the 
shaft ;  thin  poles  placed  vertically  and  horizontally,/  and  g,  pre- 
vent loose  stones  from  falling  in. 

*  Engineering,  vol.  1.,  1890,  p.  553. 


SUPPORTING  EXCAVATIONS.  241 

Special  excavations  have  to  be  timbered  according  to  circum- 
stances ;  thus  a  chamber  for  a  water-wheel  at  Clausthal  in  the 

FIG.  262. 


FIG.  263. 


Hartz  was  made  decagonal  (Fig.  263).     The  main  horizontal  pieces 
at  the  side  were  of  lo-inch  round'  timber  cut  at  the  ends  to  the 


242 


ORE  AND  STONE-MINING. 


proper  angle;  behind  them  came  half-round  timber,  trees  12  or 
14  inches  in  diameter  sawn  in  half,  arranged  vertically,  and 
finally  a  backing  of  common  planks;  the  successive  horizontal 
frames  were  kept  apart  by  studdles,  one  at  each  end  of  each  side 
of  the  polygon. 

Spilling. — When  ground  is  loose,  recourse  is  had  to  a  spilling 
process  like  that  described  for  levels.     Strong  balks  of  timber  are 

FIG.  264. 


A  — 


«>      »     * 

A 

PLAN 

c 

C 

»            »         * 

SCALE 
o        <        2        3       4.       5  FEET 

0 

METRE 

fixed  at  the  surface  or  in  solid  ground  in  the  shaft,  and  the  first 
frame  is  supported  upon  these  bearers ;  the  next  frame  is  hung 
from  the  first,  the  third  from  the  second,  and  so  on  until  the  loose 
ground  is  passed. 

In  Fig.  265  a  a  are  the  "  bearers,"  which  are  made  to  project  a 
couple  of  feet  into  solid  ground  :  upon  them  rest  the  end-pieces 
b  b  '(Figs.  264  and  265),  halved  at  the  ends  so  as  to  support  the 
two  wall-plates  c  c ;  e  e  are  two  rods  of  2 -inch  round  iron,  which 
hold  up  the  end-piece  d  of  the  second  frame  or  "  set  of  timber." 
They  are  fixed  tightly  by  means  of  cotters.  The  wall-plates  //  of 
the  second  frame  rest  upon  the  end-pieces  in  the  usual  way,  and 
when  it  becomes  necessary  to  put  in  a  third  set  or  frame,  the  end- 
pieces  g  are  hung  by  cottered  bolts  from  the  frame  above,  d  ;  h  h 
are  the  wall-plates.  The  fourth  frame  with  its  end-piece  i  and 
wall-plates  j  follows  in  the  same  manner ;  therefore,  until  the 
pressure  of  the  ground  comes  into  play,  the  bearers  a  a  are  carry- 
ing the  whole  weight  of  the  timber.  The  pieces  k  k,  known  as 


SUPPOKTING  EXCAVATIONS. 


243 


"  laths,"  are  made  of  2 -inch  plank,  9  or  10  inches  wide,  sharpened 
at  the  ends ;  they  serve  to  keep  the  loose  ground  from  falling 
into  the  shaft;  II  are  the  so-called  " tailings "  which  keep  the 
laths  in  position.  The  lath  k'  is  one  which  is  being  put  in ;  it 
has  to  be  struck  with  a  heavy  sledge  until  it  makes  its  way  into 

FIG.  265.     Sectional  elevation  along  line  A  A  of  Fig.  264. 


the  loose  ground.     If  very  heavy  blows  are  required,  the  head  of 
the  lath  is  protected  by  an  iron  shoe. 

The  piece  m  is  a  stay  put  in  for  the  purpose  of  keeping  the  set 
or  frame  in  its  place  until  the  laths  have  been  driven.  The 
frames  are  kept  at  the  proper  distance  apart,  and  the  timber 
structure  is  stiffened  by  the  usual  corner  posts  n  n  (sttcddlee). 


244 


ORE  AND  STONE-MINING. 


The  loose  ground  is  excavated  gradually,  while  each  protecting 
sheath  of  planks  is  in  process  of  being  driven  down,  and  in  due 

course   another    frame   is 

FIG.  266.  hung  on,  and  the  opera- 

tions of  driving  laths  and 
excavating  are  repeated. 

At  mines  on  the  Corn- 
stock  lode,  the  bolts  for 
keeping  the  frames  to- 
gether are  made  in  two 
parts,  with  a  tightening 
screw  in  the  middle  ;  great 
firmness  is  secured  in  this 
manner. 

Working  Places.  — 
The  timbering  of  working 
places  varies  very  greatly. 
The  simplest  case  is  that 
of  a  horizontal  bed.  Here, 
props  put  in  vertically  of  ten 

suffice  to  support  the  weight  of  the  roof.  The  addition  of  a  lid,  a 
flat  or  slightly  wedge-shaped  piece  of  board  at  the  top,  extends  the 
bearing  surface,  and,  by  presenting  a  smooth  face  to  the  top  of  the 
prop,  enables  this  to  be  forced  in  more  firmly  into  position  than  it 
could  be  against  a  rough  roof.  It  also  yields  a  little  to  the  pres- 
sure of  the  roof,  and  lengthens  the  life  of  the  prop  in  this  way. 

When  the  bed  is  inclined,  the  props  are  not  set  quite  at  right 
angles  to  the  plane  of  bedding  ;  one  reason  for  this  is  that  if  so 
set  they  might  be  easily  knocked  out  by  an  accidental  blow  from  a 
falling  stone. 

Mr.  Sawyer*  has  made  out  a  table  showing  the  deviation  from 
the  normal  which  should  be  given  : 


Set  or  Underset  of  Posts. 

Dip  of  Seam. 

Minimum. 

Maximum. 

6° 

O° 

1° 

12° 

0° 

2° 

18° 

1° 

3° 

24° 

1° 

4° 

3°° 

2° 

5° 

36° 

2° 

6° 

42° 

2° 

7° 

48° 

3° 

8° 

54° 

3° 

9° 

and  upwards 

Accidents  in  Mines  from  Falls  of  Hoof  and  Sides,  London,  1886,  p.  50. 


SUPPORTING  EXCAVATIONS. 


245 


Fig.  266,  copied  by  permission  from  Mr.  Sawyer,  is  an  instance 
of  a  prop  and  lid  for  working  in  a  bed  of  clay  ironstone. 

Logs  laid  two  by  two  crosswise  (chocks  or  cribs),  the  pigsties 
of  the  Australian  miner,  form  efficient  supports.  Fig.  267  repre- 
sents the  manner  of  using  them  in  a  bed  of  potter's  clay ;  Fig.  268, 


FIG.  268. 


FIG.  267. 


20fr 


one  of  the  huge  structures  which  may  be  seen  in  the  Wieliczka 
salt  mines ;  and  lastly,  Fig.  269,*  the  method  adopted  at  Day  Dawn 

FIG.  269. 


gold  mine,  Queensland,  in  the  case  of  a  vein.      The  pigsties  for 
supporting  the  hanging  wall  are  built  up  at  intervals  in  the  work- 

*  Kindly  furnished  by  Mr.  Joseph  Shakespear,  Government  Inspector  of 
Mines,  Queensland. 


246 


ORE  AND  STONE-MINING. 


ing  places  (stopes),  and  then  filled  up  with  rubbish  (deads,  mullock). 
The  pigsties  on  the  foot -wall  serve  to  keep  up  a  portion  of  the  vein 
until  it  is  time  to  break  it  down.  Square  timber  is  used  for 
chocks  as  well  as  round.* 

According  to  Heathcote,  the  "  square  set "  system  of  timbering, 
so  largely  used  in  the  United  States,  is  not  an  invention  of 
American  origin,  as  is  usually  supposed.  It  appears  to  have  been 


FIG.  270. 


FIG. 


known  in  Australia  as  long  ago  as  1854.  The  manner  in  which 
it  is  employed  in  Nevada  for  working  away  the  soft  "  bonanzas," 
or  ore-bodies  of  the  great  Comstock  lode  (Figs.  270,  271,  and  272) 
is  well  described  by  Hague.f  It  consists  in  framing  timbers 
together  in  rectangular  sets,  each  set  being  composed  of  a  square 

base  placed  horizontally,  formed 

FIG.  272.  of  four  timbers,  sills,  and  cross- 

pieces,  4  to  6  feet  long,  framed 
together,  surmounted  by  four 
posts  6  to  7  feet  high,  at  each 
corner,  and  capped  by  a  frame- 
work similar  to  that  of  the  base. 
These  cap-pieces,  forming  the  top 
of  any  set,  are  at  the  same  time 
the  sills,  or  base,  of  the  next 

set  above,  the  posts,  as  the  sets  rise  one  above  the  other  in  the 
stope,  being  generally  placed  in  position  directly  over  those 
below. 

"The  timbers  are  usually  of  1 2-inch  stuff,  square  hewn  or 
sawn."  Each  post  has  a  tenon  9  inches  long  at  the  upper  end, 
and  a  tenon  of  2  inches  at  the  other  end,  which  fit  into  mortices 
in  the  cap  and  sill  respectively ;  and  "  the  sills  and  caps  have 
short  tenons  on  each  end,  and  shoulders  cut  to  receive  the  ends 
of  the  post  and  the  horizontal  cross-pieces."  The  walls  of  the 
excavation  are  sustained  by  a  lagging  of  3-inch  or  4-inch  plank. 

*  Discussion  upon  Messrs.  Jamieson  and  Ho  well's  paper,  "  Mining  and 
Ore-treatment  at  Broken  Hill,  N.S.W."  Min.  Proc.  Inst.  C.E.,  vol.  cxiv., 
Session  1892-93.  Part  IV. 

t  Op.  cit.,  p.  112. 


SUPPORTING  EXCAVATIONS. 


247 


The  whole  width  of  the  ore-body  is  stoped  away  at  once,  and  its  place 
supplied  by  timbering,  and  finally  the  vacant  space  is  filled  with 
waste  rock  derived  from  dead  work  in  the  mine  or  from  special 
excavations — underground  quarries  in  fact — in  barren  ground. 
The  stoping  is  carried  on  overhand,  starting  from  an  intermediate 
shaft  or  winze,  and  Fig.  272  will  explain  how  the  different  frames 
are  built  up  one  above  the  other. 

In   the   Eureka  district,  Nevada,*  the  system  employed  for 
securing  the  chambers  left  by  the  excavations  of  the  ore-bodies  is 

FIG.  273. 


by  similar  square  sets,  but  the  mode  of  joining  the  pieces  of 
timber  presents  some  peculiarities. 

Fig.  273  is  a  general  view  of  a  square  set  employed  at  the 
Richmond  mine,  which  explains  the  manner  in  which  the 
tenons  and  shoulders  are  cut.  This  complicated  method  of 
framing  is  admitted  to  be  expensive,  but  its  adherents  claim  that 
it  possesses  great  strength.  At  Eureka  mine  the  joint  is  simpler. 
The  Eureka  timbering  is  designed  for  resisting  pressure  in  all 
directions,  the  Richmond  method  for  offering  the  greatest  resist- 
ance in  the  direction  of  the  caps,  the  ties  being  placed  parallel 
to  the  walls. 

*  Curtis,  "  Silver-lead  Deposits  of  Eureka,  Nevada,"  Mon.  U.S.  Geol. 
Survey,  vol.  vii.,  p.  154.  Washington.  1884. 


248 


ORE  AND  STONE-MINING. 


The  dimensions  of  the  pieces  between  the  shoulders  are  :  posts 
6  feet,  caps  5  feet,  ties  4  feet,  and  the  timber  employed  is  pine 


FIG.  274. 


«CJU_E  or  rceT 


from  the  Sierra  Nevada,  hewn  into  balks  12  by  12,  10  by  12,  or 
10  by  10  inches. 


SUPPORTING  EXCAVATIONS. 


249 


Square  sets  are  likewise  adopted  at  the  Broken  Hill  mines* 
where  a  wide  and  soft  lode  has  to  be  stoped  away  (Figs.  274  and 
275),  and  they  are  being  tried  in  Hodbarrow  mine  in  Cumberland. 
The  joint  used  at  Broken  Hill  t  is  represented  in  plan  by  Fig.  2  7  6,  in 
which  A  A  are  the  caps,  B  B  the  struts,  and  C  the  tenon  4  inches 


FIG. 


FIG.  277. 


FIG.  278. 

n       n 


square  on  the  end  of  the  upright  post  or  leg.  Fig.  277  explains 
the  manner  of  packing  the  hanging  wall  with  timber,  so  that  the 
load  may  be  distributed  evenly  upon  the  supporting  framework. 
It  also  shows  how  a  weak  spot 
at  A  is  further  secured  by 
horizontal  stays. 

When  additional  strength  is 
required,  a  lining  A  (Fig.  278), 
or  an  angle-stay,  B,  is  put  in  ; 
and  should  these  precautions 
appear  insufficient  to  prevent 
a  movement  of  the  ground,  the 
framework  may  be  reinforced 
in  various  ways,  as  illustrated 
by  C,  D,  E  and  F  (Fig.  278); 
F  is  a  solid  lo-inch  wall  of 
timber. 

MASONRY.— Masonry  has  long  been  used  for  supporting 
the  roof  and  sides  of  mining  excavations.  The  materials  necessary 
are  stone,  ordinary  bricks  or  slag-bricks,  and  they  may  be  built 


*   Victoria,  Annual  Report  of  the  Secretary  of  Mi1) 
p.  36. 

t  Heathcote,  op.  cit. 


for  the  Year  1889, 


250 


ORE  AND  STONE-MINING. 


up   alone   (dry  walling),  or  with  the  aid  of  mortar  or  hydraulic 
cement.      Concrete,  a   mixture  of   hydraulic  cement    and  small 

FIG.  279. 


•Scale*  of  Feet 


stones,  is  occasionally  employed,  and  probably  could  be  more  so 
with  advantage. 

Once  more  I  will  take  the  three  cases  of  a  level,  a  shaft,  and  a 
working  place. 

Levels. — In    levels   dry   walling  and   timber  are    sometimes 


FIG.  280. 


Scede. 


combined.      Thus,   after   the    excavation   of    a   wide   lode,   the 
rubbish  is  piled  up  on  the  sides,  walls  are  built  up  of  the  large 


SUPPORTING  EXCAVATIONS. 


stones,  and  caps  of  timber  are  laid  across,  which  support  the 
"  deads  "  when  the  higher  portions  of  the  lode  are  taken  away. 

Fig.  279  represents  a  level  in  an  iron  mine  in  the  Forest  of  Dean, 
where  sandstone  is  available.  The  pieces  are  hewn  and  trimmed 
roughly,  and  a  semi-circular  arch  is  made  to  rest  upon  walls  at 
each  side. 

Fig.  280  is  a  level  in  one  of  the  mines  at  Clausthal  in  the  Hartz ; 
the  sides  are  constructed  of  slag-bricks,  and  at  the  bottom  of  the 
tunnel  there  is  a  channel,  made  of  concrete,  for  carrying  water  and 
preventing  its  percolation  into  lower  workings,  which  would  other- 
wise necessitate  unprofitable  pumping. 

If  both  sides  (walls)  of  a  vein  (Fig.  281)  are  firm,  an  arch  affords 
ample  protection  when  the  ore  has  been  removed,  and  provides  a 
resting  place  for  the  rubbish  (deads,  attle  Corn.) 

A   vein   is  very  often  a  fault,  and   soft  beds  may  be  found 


FIG.  281. 


FIG.  282. 


opposite  a  hard  wall  of  solid  rock.  In  this  case  the  arch  is  made 
to  reach  from  the  roof  to  the  floor  (Fig.  282). 

One  of  the  main  crosscuts  at  Mansf  eld  *  was  lined  with  concrete 
for  a  length  of  1000  m.  (f  mile) ;  12  metres  (40  feet)  a  day  were 
put  in,  and  for  this  purpose  50  metres  (164  feet)  of  centering 
were  required.  The  laths  were  covered  with  thin  sheet-iron,  so 
as  to  prevent  the  concrete  from  sticking.  The  concrete  was  made 
of  Portland  cement,  broken  stone,  and  gravel,  in  the  proportion  of 
i  to  7,  viz.,  i  part  of  cement,  2\  of  broken  stone,  and  4jof  gravel. 
Up  to  a  height  of  16  inches  (^cTcm.)  from  the  ground,  the  layer  of 
concrete  was  made  thick  enough  to  join  on  to  the  sides  of  the 
level,  in  order  to  assure  a  firm  foundation.  Above  that  height  it 
was  made  only  6  inches  thick,  the  sides  of  the  level  having  been 
previously  built  up  with  dry  walling. 

The  centering  could  be  removed  at  the  end  of  three  days,  but  it 
was  usually  kept  in  four  or  five.  It  was  found  that  five  men  could 

*  Pamphlet  describing  the  exhibits  of  the  Mansfeld  Company  at  the 
Berlin  Exhibition  for  the  Prevention  of  Accidents,  1889,  p.  20. 


252 


ORE  AND  STONE-MINING. 


FIG.  283. 


put  in  6  m.  (20  feet)  of  concrete  lining  in  a  shift  of  twelve  hours. 
The  cost  per  running  metre  was  31  marks  70  pf.  (£i  8s.  ^d.  per 
yard). 

Shafts. — Like  levels,  shafts  are  lined  with  masonry,  brick- 
work, or  concrete,  and  these  have  the  advantage  of  being  far 
more  permanent  than  timber,  and  of  requiring  fewer  repairs. 

When  due  weight  is  given  to  the  fact  that  the  shafts  are  usually 
the  main  thoroughfares  of  a  mine,  the  necessity  of  having  a  lasting 
lining  becomes  very  evident. 

This  kind  of  shaft-lining  is  especially  desirable  in  loose  ground 
near  the  surface,  because  if  the  working  is  discontinued  tem- 
porarily, the  shaft  still  remains  secure  and  available  for  use  at  any 
future  time ;  whereas  if  timber  is  put  in,  it  soon  decays,  the  top  of 
the  shaft  collapses,  and  much  expense  is  incurred  in  the  process 
of  reopening  it. 

Another  immense  advantage  of  a  shaft  without  timber  is  its 
immunity  from  fire. 

The  section  of  walled  shafts  is  generally  circular,  as  affording 
the  best  resistance  to  pressure.  Elliptical  walling  is  also  met  with, 
and  sometimes  the  two  long  sides  are  made 
with  a  flat  curve,  and  the  two  ends  with  a 
curve  of  much  shorter  radius.  The  wall- 
ing may  be  dry  or  with  mortar,  according 
to  circumstances.  The  masonry  lining  is 
put  in  either  in  one  length,  or  in  successive 
rings  or  sections  in  descending  order,  and 
this  is  the  usual  plan. 

The  shaft  is  sunk  to  a  certain  depth 
with  a  temporary  lining  of  timber,  and 
when  firm  ground  has  been  reached,  a  bed 
is  cut  out  on  which  is  placed  a  crib  or 
curb,  A  B,  Fig.  283,*  consisting  of  seg- 
ments of  timber  forming  a  ring.  This 
serves  as  a  foundation  for  the  brickwork, 
which  is  built  up  to  the  surface ;  the  tem- 
porary timbering  is  sometimes  left  in  and 
sometimes  removed  as  the  work  progresses, 
and  any  vacant  space  is  filled  up  with  earth 
or  concrete.  Sinking  is  then  resumed,  and  of  a  smaller  diameter  for 
a  certain  distance,  so  as  to  leave  a  bracket  or  ledge  to  support  the 
curb.  On  arriving,  after  a  certain  depth  of  sinking,  at  another  firm 
bed,  a  second  curb,  C  D,  is  put  in,  and  a  second  ring  of  brickwork 
built  up.  When  the  intervening  ledge  of  rock  is  reached,  it  is 
carefully  removed  in  small  sections,  and  the  brickwork  brought 
up  to  the  first  curb.  This  process  is  repeated  until  the  shaft  is 
completed,  or  reaches  rock  in  which  no  masonry  is  requisite.  If, 


*  J.  Gallon,  Lectures  on  Mining,  vol.  i.  atlas,  plate  xxviii. 


SUPPORTING  EXCAVATIONS. 


253 


owing  to  the  nature  of  the  ground,  it  is  impossible  at  first  to  find 
firm  seats  for  the  curbs,  it  becomes  necessary  to  hang  them  by  iron 
bolts  from  a  strong  bearing  frame  at  the  surface,  or  to  support 
them  on  iron  bars  fixed  in  the  sides. 

Fig.  284  shows  a  concrete  lining  put  in  at  the  top  of  the  main 
shaft  at  Foxdale  mine,  in  the  Isle  of  Man.  The  shaft  is  rect- 
angular, 1 3  feet  6  inches  by  i  o  feet  6  inches.  The  concrete  serves 
not  only  to  support  the  sides  in  the  loose,  weak  ground  near  th& 


FIG.  284. 


HO*  .6' 


5-  4.'-  -> 


f^ 
i3$3 

*$$$ 

iSS 


>-;, 


VRD  ROCK 

7  -^'x 

*'  '•»*"* 


top,  but  also  to  keep  out  much  of  the  surface  water.  The  concrete 
was  made  of  4  parts  by  volume  of  stones  2  J  inches  to  3  inches 
across,  2  parts  of  sharp  sand  and  i  of  Portland  cement,  and  the 
total  cost  for  materials  and  labour  was  135.  6d.  per  cubic  yard. 

Some  shafts  in  Germany  have  lately  been  lined  with  concrete 
blocks  shaped  so  as  to  fit  the  curvature  of  the  sides.*  Each  block 
is  fluted  at  the  top  and  at  the  ends,  whilst  the  bottom  has  a  bead- 
ing, which  lies  in  the  channel  of  the  block  below  it.  As  the 
blocks  may  weigh  as  much  as  one-third  of  a  ton  each,  it  is  con- 
venient to  have  some  easy  means  of  handling  them.  A  vertical 
hole  is  therefore  left  in  each  block  which  receives  a  ring  bolt, 
fixed  by  a  cotter  inserted  through  a  horizontal  hole.  The  block 
can  then  be  easily  slung  to  a  rope  and  lowered  into  position,  and 
on  knocking  out  the  cotter  the  bolt  can  be  withdrawn.  The 
spaces  between  the  blocks,  and  also  the  bolt-holes,  are  filled  with 
cement ;  the  shaft  thus  receives  what  is  practically  a  solid  lining 
of  concrete,  which,  besides  supporting  the  ground,  keeps  back 
water  and  acts  the  part  of  tubbing.  As  pointed  out  by  Mr. 


*  Zeitachr.f.  B.-  H.-  u.  S.-Wesen,  vol.  xxxix.  1891,  p.  98. 


254 


ORE  AND  STONE-MINING. 


Brough,*  a  lining  of  this  kind  has  the  advantage  over  cast-iron 
and  timber  of  not  corroding  or  decaying,  besides  which  its  strength 
increases  with  age,  and  any  expansion  or  contraction  from  changes 
of  temperature  are  inappreciable.  Finally,  it  is  far  cheaper  than 
a  lining  of  brickwork  or  iron. 

The  Monier  system  consists  in  strengthening  the  concrete  by  a 
coarse  net-work  or  skeleton  of  iron  wire  embedded  in  it.  Re- 
inforced in  this  way,  the  fabric  has  greater  tensile  strength. 

Working  Places. — In  temporary  excavations,  like  working 
places,  rough  pillars,,  built  up  of  lumps  of  waste  stone  or  of  the 

FIG.  285. 


useful  mineral  itself,  will  take  the  place  of  timber  in  supporting 
the  roof,  or  may  be  used  as  an  adjunct  to  it,  as  is  the  case  in 
Fig.  285,  borrowed  from  Mr.  Sawyer,  t 

The  timber  at  the  top  serves  to  make  the  pressure  come 
gradually  upon  the  stone.'  The  post  is  eventually  drawn  out  and 
the  stone  recovered. 

Walls  are  also  built  up  with  waste  stone  enclosing  spaces  which 
are  filled  up  with  any  available  rubbish ;  and  in  some  instances 
excavations  are  entirely  packed  with  rubbish  after  the  removal  of 
the  useful  mineral. 

It  is  only  in  exceptional  cases  that  it  is  possible  to  incur  the 
expense  of  building  pillars  with  cement  or  mortar  to  support 
the  roof  and  sides  of  working  places ;  but  masonry  or  concrete 

*  "  Notes  on  the  Use  of  Cement  in  Shaft-SiDking,"  Proc.  N.  E.  Inst. 
M.  E.,  1893. 

t  Op.  cit.,  Fig.  4. 


SUPPORTING  EXCAVATIONS. 


255 


arches  may  be  constructed  for  carrying  the  rubbish  used  for  filling 
the  vacant  places  left  by  workings  upon  mineral  veins. 

METALLIC  SUPPORTS. — There  are  various  ways  of  using 
iron  and  steel  as  supports  for  levels,  shafts  and  working  places, 

Levels. — In  one  part  of  the  Halkyn  Drainage  tunnel,  Flint- 
shire, a  combination  of  cast-iron  and  wrought-iron  has  been  em- 
ployed. Much  of  the  level  is  in  hard,  solid  limestone,  and  requires 
no  lining  of  any  kind ;  but  where  small  beds  of  shale  were  inter- 
mixed with  the  harder  rock,  timber  supports  were  put  in.  As  the 
timber  originally  used  was  showing  signs  of  decay,  it  was  decided 
in  1887  to  replace  it  by  a  more  lasting  material — iron. 

The  nature  of  the  Halkyn  supports  will  be  easily  understood 
by  Fig.  286.  There  are  two  vertical  props  ov  legs,  which  are  hollow 
cylinders  of  cast-iron,  6  feet  6  inches  long,  5  inches  in  diameter 


FIG.  286. 


FIG.  287. 


-5  ins-- 


<_ g  ins. ^ 


n 


externally,  and  4  inches  internally,  with  a  flange   8   inches 
diameter  at  the  top,  and  9  inches  in  diameter  at  the  bottom. 

A  chair,  shown  in  section  by  Fig.  287,  drops  into  the  top  of  the 
iron  column,  and  receives  a  reversed  iron  rail,  7  feet  long,  weigh- 
ing 117  Ib.  (50  Ib.  to  the  yard),  the  precise  shape  of  which  is 
shown  on  a  larger  scale  by  Fig.  288.  The  iron  frames  are  placed 
about  3  feet  apart,  planks  or  rails  are  laid  from  one  to  the  other, 
and  the  space  between  them  and  the  roof  tightly  packed  with 
stones.  A  dry  stone  wall  is  built  up  on  each  side,  with  an  occa- 
sional plank  or  rail  to  make  it  firmer.  Fig.  286  also  shows  a  timber 


X*£^E 

f 

(UNIV 

V 


OF  THE 

UNIVERSITY 


256 


ORE  AND  STONE-MINING. 


"  spreader  "  above  the  water  level,  carrying  longitudinal  sleepers 
with  bridge  rails  forming  a  waggon-way  with  a  26-inch  gauge. 

This  method  of  support  is  designed  for  a  case  where  the  roof  is 
weak,  and  where  no  great  pressure  is  expected  from  the  sides.     It 


FIG.  288. 


FIG.  289. 


would  evidently  be  unsuitable  for  the  Cornish  County  adit  in 
Gwennap,  because  the  water  would  speedily  eat  away  the  iron. 
In  the  Halkyn  adit,  however,  no  corrosion  need  be  feared ;  for 
iron  rails  which  were  laid  near  the  mouth  of  the  tunnel  very  many 
years  ago  have  not  been  injured  by  the  water.  Its  cheapness,  as 
compared  with  the  cost  of  the  walling,  was  the  reason  why  iron 
was  adopted  in  Flintshire.  It  was  estimated  that  to  secure  this 
part  of  the  adit  with  the  best  Buckley  brick  and  hydraulic  lime, 
would  cost  over  ^4  per  yard,  whereas  the  present  method  has  cost 
only  £2  45.  per  lineal  yard  of  tunnel,  It  cannot  be  denied  that 
a  brick  lining  would  be  more  permanent,  as  the  planks  in  the  roof 
of  the  level  will  have  to  be  replaced  from  time  to  time  ;  but  the 
cost  of  repairs  is  likely  to  be  slight.  In  more  recent  work  iron 
rails  and  old  fire-bars  are  used  instead  of  wooden  lagging. 

Steel  beams  have  been  used  with  success  for  some  years  at  the 
Nunnery  Colliery,  Sheffield,  in  the  place  of  timber.  They  are  of 
I-section,  4  inches  wide,  5  inches  deep,  with  the  web  f  inch  thick 
(Fig.  289),  and  they  are  considered  by  Mr.  Bainbridge,  the  manag- 
ing director  of  the  colliery,  to  be  of  the  same  strength  as  1 2-inch 
Norway  balk.  The  beams  are  supplied  in  lengths  of  6,  7,  8,  9, 
and  10  feet,  so  as  to  suit  drivages  of  various  widths.  There  are 
two  ways  of  using  them — (i)  as  "  bars,"  or  caps,  resting  upon  the 
timber  legs;  (2)  as  legs  and  caps. 

Fig.  290  shows  the  former  method — a  horizontal  cap,  10  feet 
long,  rests  upon  two  legs  of  round  Norway  timber,  8  to  10  inches  in 
diameter,  and  a  lug  or  band  of  wrought  iron,  i§  inch  by  J  inch, 
shrunk  on,  prevents  the  leg  from  coming  in  sideways.  The 
frames  or  sets  are  generally  placed  3  feet  apart,  and  old  timber 
laid  across  from  cap  to  cap  forms  the  so-called  lofting  supporting 
the  roof. 

The  steel  beams  are  tarred  over  with  unboiled  gas  tar,  and 
some  have  been  in  use  several  years  without  showing  any  signs  of 
deterioration,  whereas  the  average  life  of  English  larch  or  Norway 
timber,  at  this  colliery,  is  only  two  years. 


SUPPORTING  EXCAVATIONS. 


257 


The  beams  cost  about  ^5  105.  per  ton,  delivered  at  the  colliery ; 
in  other  words,  a  ro-foot  beam  costs  8s.  A  beam  of  Norway  timber 
10  feet  by  12  inches  by  12  inches  would  contain  10  cubic  feet, 
and  at  8^d.  per  cubic  foot,  would  cost  75.  id.  The  difference  in 
original  cost  is  therefore  not  very  great. 

FIG.  290. 


Scale 


Inches    12  6   0        1        2 


~8 9  '-  10  Feet 


The  advantages  of  the  steel  over  timber  beams  are  numerous : 

1.  Greater  durability,  which  means  a  great  reduction  in  the 
cost  of  repairs. 

2.  Possibility  of  using  the  beams  elsewhere  when  taken  out. 
If  bent  slightly,  they  can  be  reversed ;  if  badly  knocked  about, 
they  can  be  sent  to  the  steel  works  and  worked  up  again.     In  any 
case,  they  are  of  some  value, 

3.  Lightness  and  handiness.     A  ic-feet  steel  beam  weighs  166 
Ibs. ;  a  lo-feet  beam,  12  inches  square,  of  Norway  timber,  weighs 
3  cwt.     The  steel  beams  are  not  only  lighter,  but  also  less  bulky, 
and  consequently  more  easily  handled.     Therefore  men  can  do 
more  work  in  a  given  time. 

4.  Increased  space  for  ventilation.     The  free  space  in  a  level 
will  be  from  5  to  7  inches  higher  with  steel  than  with  timber  in 
lining  an  excavation  of  a  given  size.     Six  inches  added  to  a  height 
of  6  feet  means  an  increase  of  i-i2th,  or  8|  per  cent.,  in  the  area 
of  the  airway. 

5.  Less  deterioration  of  the  air  of  the  mine  by  decaying  timber. 

6.  No  danger  from  fire. 

When  girders  are  used  as  legs  as  well  as  caps  (Fig.  291),  a  plate 

B 


258 


ORE  AND  STONE-MINING. 


of  rolled  steel,  of  the  shape  shown  in  Figs.  292  and  293,  is  placed 
at  each  extremity  of  the  leg.     The  plate  is  J  inch  thick,  6^  inches 


FIG.  291. 


FIG.  292. 


FIG.  293. 


FIG.  294. 


long,  by  6  inches  wide,  with  a  slot  J-  inch  wide  and  2  ^  inches  long. 
The  web  of  the  leg  passes  into  this  slot  and  is  thus  prevented  from 
slipping  sideways,  while  the  turned-up  rim  prevents  slipping  out- 
wards or  inwards. 

Lugs  of  wrought  iron  are  shrunk  on  to  the  cap  as  in  the 
previous  case. 

In  making  the  comparison  of  cost,  it  is  necessary  to  recollect 
that  I  have  chosen  a  case  extremely  favourable  to  steel,  because 
the  beams  are  made  at  Sheffield,  and  any  waste  material  can  be 

worked  up  again  on  the  spot  with- 
out having  to  pay  a  heavy  cost  of 
carriage  back  to  the  steelworks. 

One  kind  of  joint  used  in  Bel- 
gium* for  I -iron  is  a  flanged 
bonnet  of  cast-iron,  which  receives 
the  top  of  the  leg  and  one  end  of 
the  cap.  A  wooden  wedge  is  placed 
in  the  bonnet  under  the  cap,  so  as 
to  give  a  certain  amount  of  elas- 
ticity to  the  frame. 

In  doing  work  with  a  new  ma- 
terial, a  servile  imitation  of  the  old 
forms  is  often  remarked.  The  fact 
of  timber  being  most  readily  obtainable  in  straight  pieces  naturally 
led  to  the  adoption  of  rectangular,  trapezoidal  or  polygonal  forms 
for  supporting  linings  ;  but  there  is  no  necessity  with  iron  or  steel 
for  copying  the  shapes  which  are  most  suitable  with  wood.  This 
was  recognised  by  the  Germans  in  the  early  days  of  iron  supports. 
A  method  in  use  in  the  Hartzin  1872  consisted  in  bending  an  iron 

*  Habets,  "Le  materiel  et  les  precedes  de  1'Exploitation  des  Mines," 
Extraits  des  Rapports  du  Jury  International  des  ^Recompenses  de  V Exposition 
Unwerselle  d'Anvers,  1885.  Paris  and  Liege,  1887,  p.  61. 


SUPPORTING  EXCAVATIONS. 


259 


rail  as  shown  by  Fig.  294,  and  making  it  support  other  rails  laid 
longitudinally,  against  which  flattish  stones  were  placed ;  the 
vacant  place  between  these  and  the  rock  was  filled  with  rubbish. 
The  ends  of  the  rails  were  footed  in  holes  cut  in  large  stones. 

FIG.  295. 


Some  neat  and  effective  forms  of  steel  supports  are  made  in 
France,  where  more  attention  has  been  paid  to  the  subject  than 
in  this  country. 
£."  Three  kinds  made  of  I-steel  by  the  "  Societe    anonyme   des 

FIG.  296. 


Hauts-Fourneaux,  Forges  et  Acieries  de  Denain  et  d'Anzin,"  will 
serve  as  good  examples  of  steel  supports  for  levels. 

Fig.  295  is  a  slightly  bent  bar,  the  ends  of  which  are  made  to 


260 


ORE  AND  STONE-MINING. 


FIG.  297. 


rest  upon  dry  walls  at  the  sides  of  a  level.  It,  therefore,  takes 
the  place  of  an  arch.  Fig.  296  represents  a  favourite  form  of 
lining  for  levels  ;  it  is  composed  of  two 
side-pieces  suitably  bent  at  the  top,  and 
united  by  a  couple  of  fish-plates  (Fig. 
297)  and  four  bolts  ,•  in  some  cases  a 
cast-iron  sleeve  is  used  instead  of  the 
fish-plates.  When  the  floor  is  soft  and 
liable  to  "  creep,"  the  frame  may  be 
made  of  three  pieces  (Fig.  298). 

Some  mines  utilise  old  rails,  weigh- 
ing 36  to  40  Ibs.  per  yard  (18  to  20  kil. 
per  metre)  for  frames.  The  rails  are 
bent  into  semicircles,  and  two  of  these 
are  united  by  sleeves  of  riveted  sheet- 
iron,  in  which  they  are  kept  tight  by 
wooden  wedges.  Elliptical  frames  are 
used  in  the  Freiberg  district,  made  of 
two  pieces  of  rail  held  together  by  a 


"-    -    -    -    SQmnt  - 


couple  of  fish-plates  at  the  top  and  bottom. 


FIG.  298. 


SCALE.  OF    FEET 


1234- 
SCALE.    OF  METRES 


O.5* 


SUPPORTING  EXCAVATIONS. 


261 


The  frames  made  by  the  "  Compagnie  des  Fonderies  et  Forges 
de  1'Horme  "  (Loire)  are  almost  invariably  composed  of  two  semi- 
circles of  mild  steel.  Two  kinds  of  sections  are  employed— 

FIG.  299. 


FIG.  300. 


namely,  channel  steel  and  bulb  tee  steel.     Bars  of  channel  steel,  70 

mm.  x  40  mm.,  weighing  16  Ibs.  to  the  yard,  are  sawn  into  proper 

lengths  on  leaving  the  rolls,  and  while  still 

hot  are  bent  into  semicircles.     The  ends 

are  carefully  planed  square,  so  that  the  top 

semicircle   may   rest   accurately  upon   the 

lower  one  (Fig.  299).     They  are  joined  by 

sleeves  made  of  sheet-steel,  fixed  by  a  couple 

of   small   iron  wedges   (Fig.    300).     It   is 

claimed  by  the  Horme  Company  that  these 

frames  never  give  at  the  joint. 

Steel  of  bulb  tee  section,  weighing  26  Ibs.  per  yard,  is  employed 
for  heavier  ground  (Fig.  301).  The  sleeves  are  made  of  riveted 
sheet-steel,  and  are  fixed  by  two  wooden  wedges,  one  on  each  side 
of  the  web  (Fig.  302).  Bars  of  U -steel  of  a  hollow  semicircular 
section  are  used  as  the  lagging ;  the  steel  is  J  inch  thick  and  about 
i  J  inch  in  diameter,  weighing  scarcely  2  Ibs.  per  yard  (i  kilo,  per 
metre),  and  it  is  usually  cut  in  lengths  just  sufficient  to  go  from 
one  frame  to  the  next.  Small  bars  of  steel  of  square  section 
are  employed  for  the  same  purpose. 


262 


ORE  AND  STONE-MINING. 


Iron  and  steel  may  be  used  with  advantage  instead  of  timber 
for  the  construction  of  supporting  platforms  (stulls)  in  vein- 
mining.  At  Freiberg*  full-sized  rails  are  employed  as  cross- 
beams (stull-pieces) ;  they  are  covered  with  small  mine  rails, 


FIG.  301. 


FIG.  302. 


and  these  with  flat  stones.  Where  the  pressure  is  not  very 
great,  wire  rope  is  used  for  the  covering.  The  rope  is  cut  into 
pieces  about  2  metres  long,  and  the  ends  are 
welded  up  and  bent  into  hooks.  These  pieces 
are  laid  across  the  iron  stull-pieces  and 
covered  with  stones  and  rubbish. 

In  places  where  the  two  walls  of  a  lode  are 
likely  to  come  together  a  little  after  a  time,  the 
stull-pieces  are  cut  about  i  or  ij  inch  shorter 
than  required,  and  a  wooden  wedge  is  put  in  at 
each  end.  The  pressure  of  the  ground  squeezes 
up  the  wedges  gradually,  and  finally  the  rock 
comes  against  the  iron.  The  rails  used  as  stull- 
pieces  are  often  slightly  arched  so  as  better  to 
support  the  weight  of  the  rubbish,  and  the  flange  of  the  rail  is 
placed  underneath,  as  its  long  straight  edge  gives  a  better  hold  in 
the  rock  than  its  head.  The  rails  are  not  cut  across  at  right  angles 
to  their  length,  but  are  made  somewhat  longer  above  than  below, 

*  freibergs  Berg-  und  JHuttenwesen,  Freiberg  i.  S.,  1893,  P-  I7^- 


SUPPORTING  EXCAVATIONS. 


263 


in  order  that  they  may  not  drop  through  if  small  pieces  of  rock 
break  off  under  them.  In  addition  to  all  sorts  of  small  rails, 
old  fire-bars  and  old  boiler-plates  are  occasionally  utilised  for 
"  lagging." 

A  new  departure  in  driving  tunnels  in  soft  ground  is  furnished 
by  the  Greathead*  shield,  by  the  aid  of  which  two  long  parallel 
tunnels  have  been  driven  through  clay  and  gravel,  in  London, 
for  passenger  traffic  by  an  electric  railway.  As  cases  may  arise 
in  mines  where  this  method  would  be  available,  it  is  desirable  to 
explain  briefly  the  mode  of  working  adopted,  and  to  indicate  the 
sources  where  full  details  will  be  found.  The  tunnels  of  the  City 
and  South  London  Railway  may  most  easily  be  described  as  long 
tubes  of  cast  iron,  built  up  ring  after  ring  as  the  excavation  pro- 
gressed. The  rings  are  i  foot  7  inches  long,  made  in  seven  seg- 
ments bolted  together  by  f -inch  bolts  passing  through  the  internal 
flanges.  They  therefore  closely  resemble  the  watertight  lining  of 
shafts  known  as  "  tubbing,"  to  which  reference  will  be  made  later. 

The  ground  in  the  centre  part  of  the  end  of  the  tunnel  was  dug 
out,  and  a  cylindrical  shield  was  forced  forward  by  hydraulic 
jacks.  The  shield  had  a  cutting  edge  and  penetrated  into  the 
clay  under  the  pressure.  The  clay  was  removed  as  the  shield 
went  forward,  and  at  last,  when  the  advance  amounted  to  20 
inches,  a  new  ring  was  formed  by  bolting  together  the  segments, 
which  then  exactly  fitted  the  inside  of  the  shield.  The  progress 
of  the  shield  left  an  annular  empty 
space  1 1  inches  deep  between  the 
last  ring  and  the  surrounding  clay, 
equal  to  the  thickness  of  the  shield. 
This  was  filled  by  injecting  Lias 
lime  grout  through  a  hole  in  each 
segment,  and  so  encasing  the  tunnel 
in  concrete.  The  average  progress 
per  day  was  13  feet  6  inches. 

When  the  tunnel  came  to  water- 
bearing gravel  and  sand,  it  was 
necessary  to  have  an  air-lock  and 
keep  the  water  back  by  compressed 
air.  In  order  to  prevent  the  escape 
of  air  into  the  porous  gravel,  the 
face  was  cut  away  in  sections,  and  as  each  portion  was  exposed,  a 
jet  of  grout  was  played  upon  it  to  close  the  interstices. 

Shaft  Linings  of  Iron. — Fig.  303  shows  a  method  of  temporary 
support  for  sinking  little  shafts  30  or  40  feet  deep.  Iron  rings, 
4  feet  6  inches  to  8  feet  in  diameter  are  employed  to  keep  lining 
planks  in  position.  The  rings  are  made  in  two  or  three  segments, 
bolted  together  inside.  The  iron  used  is  from  ij  to  2\  inches 
wide  by  \  inch  thick.' 

*  Engineering,  vol.  1.,  1890,  p.  551. 


FIG.   303. 


OFTHF 


264 


ORE  AND  STONE-MINING. 

FIG.  304. 


FIG.  305. 


SUPPORTING  EXCAVATIONS. 


265 


FIG. 


The  rings  may  be  hung  one  from  the  other  by  iron  hooks,  and 
channel  iron  may  take  the  place  of  the  flat  iron  in  the  circles 
around  the  shaft. 

Steel  and  iron  rings  are  also  used  in  the  case  of  permanent 
supports  for  shafts.     The  accompanying  figure  (304)  shows  the 
lining    of    a   shaft   at    Boryslaw,    adopted  by   Herr   Platz,   the 
director  of  the  ozokerite  mines  be- 
longing to  the  "  Compagnie  Cem- 
merciale    Frangaise."      The  shaft 
is  kept  open  in  very  heavy  ground 
by  rings   of   channel  iron  placed 

1  metre  apart  from  centre  to  cen- 
tre.    Each   ring  is  made  in  two 
halves  arid  these  are  connected  by 
two  special    castings,   with   holes 
for  bolts  ;  they  act  the  part  of  fish- 
plates, two  bolts  being  on  one  side 
of  the  joint,  and  two  on  the  other. 
Around  the  rings  come  oak  planks, 

2  inches  thick,  and  there  are  four 
distance  pieces  (studdles  or  posts) 
between    every   two    rings.      At 
intervals  of   2    or  3  metres,  two 
oak  bearers  are  placed  across  the 
shaft,  which  serve  to  take  up  the 
weight  of  the  rings  if  necessary, 
though,  as  a  rule,  the  pressure  of 
the  ground  holds  the  rings  very 
firmly.      The     bearers    are    also    ,_ 
utilised   for  carrying   the   guides    ° 
or  conductors  for  the  cage. 

Fig.  305  represents  a  ring  simi-  o  '  *  '  *  '  »  '  »  '  .0  '  ,*  ',*',»'  ,B  ao 
lar  to  those  used  at  Boryslaw, 

made  by  the  Witkowitz  Ironworks  for  a  shaft  8  feet  6  inches  in 
diameter,  and  Fig.  306  gives  the  details  of  the  connecting  piece 
and  bolts. 

Working  Places. — We  may  start  with  simple  cast-iron  props 
used  instead  of  timber  in  places  where  they  can  be  withdrawn. 
They  are  rather  heavy,  but  they  will  serve  over  and  over  again. 
At  some  collieries  a  large  number  of  these  props,  from  3  feet 
6  inches  to  5  feet  6  inches  long,  are  employed,  and  they  appear  to 
give  satisfaction.  Naturally  they  have  to  be  made  of  the  same 
height  as  the  particular  seam  which  is  worked,  but  any  minor 
irregularities  in  the  roof  are  suited  by  the  thickness  of  the  lid,  or 
by  making  the  lid  of  two  pieces  of  board.  They  are  set  with  the 
small  end  downwards.  Cast-iron  props  are  not  suited  for  resisting 
cross  pressures,  and  they  are  liable  to  break  occasionally  when 
they  happen  to  fall. 


SCAL.E      OF      INCHES 


SCALE     OF    MILLIMETRES 


266 


ORE  AND  STONE-MINING. 


Howell's  prop  is  a  hollow  lap-welded  steel  tube  or  pipe, 
4  inches  in  diameter  outside,  with  the  ends  expanded  till  they 
are  slightly  conical,  in  order  that  the  top  may  receive  a 
wooden  plug  which  projects  about  f  inch  above  the  steel.  These 
props  are  used  alone  in  working  places,  or  in  conjunction  with 
bars  of  I-steel,  to  support  the  roadways.  The  foot  of  the  prop 
in  this  case  is  set  out  about  6  inches  in  the  bottom  so  as  to  pre- 
vent it  from  coming  in  sideways.  The  object  of  the  plug  is  to 
obtain  a  certain  amount  of  elasticity. 

A  third  kind  of  prop  is  made  of  I-iron  or  steel,  either  cut  off 
square  or  with  the  web  cut  out  for  a  few  inches,  and  the  two 
flanges  turned  over  so  as  to  make  ends  with  a  larger  bearing 


FIG.  307. 


FIG.  308. 


surface  (Fig.  307).  The  holes  a  a  enable  the  props  to  be  with- 
drawn by  a  hook. 

WATERTIGHT  LININGS  FOR  SHAFTS.— We  must 
now  turn  to  the  special  case  of  shafts  which  have  to  pass 
through  watery  strata.  Here  it  is  often  advisable  to  put  in  a 
watertight  lining,  in  order  to  prevent  the  inflow  of  water,  and  so 
save  the  expense  of  pumping  it  out  day  after  day,  and  year  after 
year. 

The  lining  may  be  made  of  wood,  brick,  and  hydraulic  lime  or 
cement,  or,  lastly,  iron. 

There  are  two  kinds  of  wooden  tubbing:  (i)  Plank  tubbing, 
whence  this  kind  of  lining  originally  received  its  name;  and 
(2)  solid  timber  tubbing.  Plank  tubbing  is  made  of  boards  from 
2  to  3  inches  thick,  arranged  vertically  round  the  shaft  and  cut 
with  a  bevel  like  the  staves  of  a  cylindrical  barrel.  The  planks 
are  nailed  on  to  rings  of  wood  placed  at  suitable  intervals. 


SUPPORTING  EXCAVATIONS.  267 

Solid  wooden  tubbing  (Fig.  308)  consists  of  carefully  shaped 
blocks  of  oak  or  elm,  with  thin  sheets  of  deal  placed  between  the 
joints.  The  joints  are  wedged  up  as  tightly  as  possible,  and  a 
lining  of  this  kind  can  be  made  so  as  to  resist  a  very  considerable 
pressure  of  water,  even  200  to  300  Ibs.  per  square  inch.* 

The  method  known  as  "  coffering  "  consists  in  lining  the  shaft 
with  a  wall  made  of  brick  and  cement,  or  brick  and  hydraulic 
lime,  and  backing  this  up  with  puddled  clay.  It  is  specially  used 
for  keeping  back  the  surface-water. 

Full  details  concerning  this  method  will  be  found  in  the  paper t 
quoted  below,  and  my  description  may  be  very  brief.  In  one 
particular  instance  the  shaft  received  first  of  all  a  temporary 
lining  of  g-inch  brickwork  put  in  dry  during  the  course  of  sinking, 
the  successive  sections  being  held  up  by  wooden  cribs  or  curbs — 
that  is  to  say,  rings  of  oak  placed  4  to  5  feet  apart.  Each  ring 
was  hung  from  the  one  above  it  by  vertical  pieces  of  i  J-inch  plank 

FIG.  309. 


spiked  on  to  both  rings.  When  firm  ground  below  the  watery 
strata  had  been  reached,  a  level  bed  was  cut  for  putting  in  the 
wedging-crib — a  ring  made  of  segments  of  cast-iron,  either  like 
A  or  B  in  section  (Fig.  309).  By  means  of  wedges  driven  in 
behind,  it  was  made  perfectly  tight  and  stanch.  Three  courses 
of  brickwork  made  with  Roman  cement  were  built  up  on  the  crib 
and  the  wedges  behind  it ;  they  formed  the  foundation  for  the 
"coffering  "  proper,  which  consisted  of  three  rings  of  brickwork  in 
hydraulic  mortar  EE  (Fig.  310),  separated  by  the  two  rings  of 
hydraulic  mortar  F  F,  and  the  puddled  clay  D.  B  represents  the 
original  lining  of  nine  inches  of  dry  brickwork  put  in  against  the 
watery  strata.  As  water  running  down  the  sides  of  the  shaft 
would  render  it  impossible  to  carry  out  this  kind  of  work  satis- 
factorily, means  had  to  be  adopted  for  getting  rid  of  it.  A 
garland  or  circular  launder  was  fixed  around  the  shaft  so  as  to 
intercept  it  before  it  could  interfere  with  the  work  of  coffer- 
ing, whilst  water  coming  in  behind  the  coffering  was  drawn  off 
during  the  progress  of  the  work  by  placing  a  vertical  launder 
against  the  preliminary  lining  of  bricks.  This  launder  was  pierced 
with  holes  every  three  inches,  and  communicated  at  the  bottom 

*  E.  Bainbridge,  "  On  the  Kind-Chaudron  System  of  Sinking  Shafts 
through  Water-bearing  Strata,"  Proc.  List.  C.E.,  vol.  xxxiv.,  1871-1872, 
Plate  12. 

t  N.  K.  Griffith,  "  On  the  Coffering  of  Shafts  to  keep  back  Water," 
Trans.  N.  Eny.  Inst.  Min.  Mech.  Eny.,  vol.  xxvi.,  1876-77,  p.  3. 


268 


ORE  AND  STONE-MINING. 


with  a  block  of  wood  which  had  a  3-inch  hole  bored  through  it, 
opening  into  the  shaft  just  above  the  wedging-crib.     As  it  became 

FIG.  310. 


Scale  of  Feel 

I"  6"?*  o I 2 

gradually  buried  by  putting  in  the  clay  D,  the  holes  were  plugged 
up,  and  finally  the  launder  was  filled  with  pieces  of  stone,  and 
cement  was  run  in. 

The  walling  was  done  with  hydraulic  mortar,  ma'de  of  one  of  blue 
lias  lime  to  two  of  sand,  and  the  middle  course  was  grouted  in, 
either  with  a  similar  mixture  or  with  pure  Roman  cement. 

The  advantage  of  coffering  over  the  ordinary  metallic  lining 
known  as  tubbing  is  its  cheapness.  Mr.  Griffith  puts  the  cost  of 
coffering  a  shaft  he  sank  at  £10  55.  per  yard,  and  he  estimates 
that  a  suitable  cast-iron  tubbing  would  have  cost  ,£23  per  yard. 
The  pit  was  20  feet  in  diameter  clear  within  the  original  lining  of 
dry  bricks,  and  as  the  coffering  was  2  feet  thick,  the  final  diameter 
of  the  pit  was  reduced  to  16  feet. 

Where  the  ground  is  soft,  a  cast-iron  lining  may  be  made  to 
sink  down  by  its  own  weight  and  by  pressure  applied  to  it.  This 
process  was  adopted  at  Restronguet  Creek,*  a  branch  of  Falmouth 
Harbour,  in  order  to  work  a  bed  of  stream-tin.  The  creek  had 
10  or  12  feet  of  water  at  high  tide,  and  was  nothing  but  a  mud- 
bank  at  low  tide.  A  staging  was  constructed  upon  piles  in  the 
creek,  in  order  to  have  room  for  working,  and  a  first  cylinder,  with 

*  Taylor,  "  Description  of  the  Tin  Stream  Works  in  Restronguet  Creek, 
near  Truro,"  Proc.  Inst.  M.E.,  1873,  p.  155. 


SUPPORTING  EXCAVATIONS. 


269 


a  cutting  edge,  was  placed  upon  the  mud,  two  more  cylinders 
were  then  bolted  on,  and  their  weight  caused  the  whole  to  sink 
down.  The  cylinders,  made  of  cast-iron,  were  6  feet  high  by  6  feet 
in  diameter  and  i|  inch  thick,  and  they  were  joined  by  internal 
flanges  faced  in  the  lathe.  Each  ring  weighed  about  2^  tons, 
and  was  lowered  by  a  crane  through  an  opening  in  the  stage, 
between  guides  in  order  to  keep  it  vertical.  When  the  first 
three  rings  had  ceased  to  sink,  the  mud  inside  was  cleared  out, 
and  further  cylinders  were  added  and  forced  down  by  pressure 
from  the  chain  of  a  crab-winch.  Afterwards  an  ingenious  method 
of  taking  advantage  of  the  rise  and  fall  of  the  tide  was  resorted  to. 
A  huge  girder  was  laid  across  the  top  ring,  and  a  barge  laden 
with  stone  was  attached  to  each  end.  The  fastening  was  made 
complete  at  high  water,  and  when  the  tide  fell  the  full  weight  of 
the  barges  came  npon  the  girder,  and  so  upon  the  shaft.  The 
cylinder  was  thus  sunk  to  the  full  depth  without  difficulty. 
During  the  sinking  the  core  was  always  cleared  out  a  little  below 
the  bottom  of  the  cylinder  before  the  barges  were  attached,  and, 
if  left  for  a  day,  the  mud  was  found  to  swell  up  3  or  4  feet  into  it. 
A  total  weight  of  about  250  tons  was  required  to  sink  the  cylinder 


FIG.  311. 


&J&T. 


\ 


as  it  neared  the  bed  of  tin  ore.     Altogether,  thirteen  of  the  6-feet 
rings  were  sunk,  making  a  total  depth  of  78  feet. 

The  ordinary  method  of  tubbing  is  that  in  which  the  rings  are 
made  up  of  segments,  and  as  a  rule  the  cylinder  of  cast-iron  plates 
is  built  up  within  some  temporary  lining ;  this  is  carried  down 
until  it  reaches  some  solid  and  impervious  stratum  below  the 


270 


OEJE  AND  STONE-MINING. 


water-bearing  measures,  fit  to  serve  as  a  foundation.  When  such 
a  stratum  has  been  found,  the  sinking  is  continued  for  a  few  feet, 
and  a  bed  is  cut  out  very  carefully,  and  trimmed  perfectly  even  and 
horizontal,  so  as  to  receive  the  first  crib  or  curb  similar  to  those 
just  described  in  the  case  of  coffering.  The  curb  is  a  hollow  ring 
of  cast-iron  made  in  segments  about  4  feet  long.  Strips  of  deal 
about  J-inch  thick  are  placed  between  every  joint,  and  the  seg- 
ments are  brought  tightly  together  by  wedging  up  the  space  be- 
tween the  outside  of  the  curb  and  the  rock.  The  joints  are  finally 
rendered  perfectly  stanch  by  driving  in  wedges  into  the  deal  strips. 
A  second  curb  is  laid  upon  the  first,  with  intervening  strips  of  deal, 
and  the  wedging  process  repeated  ;  sometimes  a  third  curb  comes 
upon  the  second.  The  top  curb  is  the  foundation  for  the  tubbing 
proper,  which  is  built  up  segment  after  segment.  The  segments 
are  usually  i  to  3  feet  high  and  4  feet  long  (Fig.  311);  their  thick- 
ness depends  upon  the  pressure  of  water  they  have  to  withstand 
and  varies  between  \  inch  and  3  J  inches.  They  are  smooth  inside, 
but  are  strengthened  with  flanges  and  ribs  on  the  side  turned 
towards  the  ground. 

The  segments  a,re  kept  in  place  by  wedging  them  against  the 
sides  of  the  pit,  and  filling  up  the  interspace  with  earth  or  con- 
crete ;  thorough  stanchness  is  secured  by  interposing  a  half -inch 

strip  of  deal  or  pitch  pine  at 
every  joint,  and  finally  driving 
in  wedges  when  all  the  tubbing 
is  fixed.  Water  coming  in  from 
the  surrounding  strata  is  al- 
lowed to  escape  through  the 
central  hole  of  each  segment. 
A  cast-iron  lining  cylinder 
(Figs.  312  and  313)  is  thus 
built  up  inside  the  shaft  until 
an  impervious  stratum  above 
the  water-bearing  ground  is 
reached ;  another  wedging  curb 
then  completes  the  tubbing. 
The  joints  are  wedged  up  as 
tightly  as  possible,  and  finally 
plugs  are  driven  into  the  cen- 
tral holes  of  the  segments.  If 
the  work  has  been  properly  performed,  the  lining  will  be  water- 
tight. The  tubbing  is  sometimes  put  in  by  a  succession  of  com- 
paratively short  sections,  each  resting  upon  its  own  wedging  curb, 
and  shutting  off  a  portion  of  the  water-bearing  beds.  If  this 
method  is  pursued,  each  separate  section  is  continued  upwards  to 
the  next  wedging  curb  above,  resting  upon  a  bracket  of  rock ; 
this  is  cut  away  very  carefully  in  small  sections,  and  the  last 
ring  of  segments  made  to  join  it  exactly.  When  the  amount  of 


FIGS.  312  &  313. 

I 


SUPPORTING  EXCAVATIONS.  271 

water  is  not  excessive,  it  is  usual  to  sink  through  the  whole  of 
these  strata  before  setting  a  wedging  curb  and  fixing  the  seg- 
ments.* 

In  a  few  cases  no  temporary  lining  is  used,  and  the  segments 
are  at  once  inserted  in  descending  order,  each  ring  hanging  from 
the  one  above  it.  After  several  rings  have  been  so  fixed,  a 
bearing-ring  is  put  in  and  the  wedging  of  the  joints  proceeded 
with.  This  process  is  repeated  until  strata  are  reached  which 
require  no  such  lining. 

SPECIAL  PROCESSES.— The  amount  of  water  met  with 
has  been  sometimes  so  great  as  to  render  sinking  by  the  ordinary 
methods  quite  impossible,  on  account  of  there  not  being  room 
enough  in  the  shafts  for  fixing  pumps  sufficiently  large  to  cope 
with  the  enormous  feeders  of  water,  and  even  where  pumping  is 
possible  the  expense  may  render  it  out  of  the  question.  A  few 
figures  quoted  by  Mr.  Bainbridge  t  will  give  some  idea  of  the 
enormous  cost  due  to  water-bearing  beds.  In  Germany  the  sink- 
ing of  a  pit,  only  239  feet  deep,  cost  ^96,000,  and  occupied  40 
months,  although  the  quantity  of  water  pumped  was  only  606 
gallons  per  minute.  For  another  pit  the  corresponding  figures 
were  570  feet,  ^£140,000,  91  months,  2200  gallons.  Taking 
eleven  cases,  it  appears  that  the  cost  varied  between  ^36  and 
^245  per  foot  of  sinking,  and  that  the  average  rate  at  which  the 
sinking  progressed  varied  from  3-9  to  17-2  feet  per  month. 

For  dealing  with  cases  of  this  kind,  there  are  three  principal 
methods  of  sinking  which  deserve  special  mention:  (i)  Kind- 
Chaudron  or  boring  method;  (2)  Triger  or  compressed  air 
method;  (3)  Poetsch  or  freezing  method. 

Boring  Method. — Kind's  process  as  improved  by  Chaudron 
consists  briefly  in  boring  out  the  shaft  by  means  similar  to  those 
employed  for  searching  for  mineral,  and  then  lowering  into  the 
pit  so  formed  a  watertight  lining  of  cast-iron,  which  can  be  made 
stanch  at  the  bottom  even  under  water.  The  great  advantage  of 
this  process  is  that  there  is  no  pumping  at  all  until  the  operations 
of  sinking  and  lining  are  complete  ;  and  then,  indeed,  it  is  only  the 
contents  of  the  shaft  itself  that  have  to  be  drawn  up. 

The  various  stages  of  the  process  are  as  follows  : — 

(1)  Alternately  boring  a  small  pit  in  advance,  and  enlarging  it 
by  a  bigger  tool  to  the  full  size  of  the  shaft. 

(2)  Preparing  a  seat  for  the  moss-box. 

(3)  Lowering  the  water-tight  lining  (tubbing)  with  its  moss-box 
at  the  bottom. 

(4)  Putting  in  the  outside  lining  of  concrete. 

(5)  Pumping  out. 

This  process  has  been  frequently  described  at  great  length,  and 
persons  who  require  more  details  than  can  be  given  in  a  general 

*  Bainbridge,  ibidem.  t  Ibidem. 


272 


ORE  AND  STONE-MINING. 


FIG.  314. 


text-book  will   do  well  to  consult  the  original  papers  mentioned 

below.* 

The  preliminary  pit  is  bored  4  or  5  feet  in  diameter,  and  is 

always  kept  well  in  advance  of  the  full-sized  shaft,  generally  from 

30  to  100  feet. 

The  tool  used  is  a  compositejjorer  with  fourteen  cutting  chisels  a 

fixed  in  round  sockets  (Fig.  314).  Above  the  chisels  there  is 
the  cross-piece  6,  with  two  cutters,  which  serve 
to  trim  off  any  slight  irregularities ;  at  the  same 
time  it  acts  as  a  guide,  and  so  tends  to  ensure  the 
verticality  of  the  hole.  There  is  also  a  second 
guide  c  above  it,  without  teeth.  The  total  weight 
of  this  tool  is  from  7  to  8  tons.  It  is  suspended 
from  a  series  of  pitch-pine  rods,  each  58  to  59  feet 
in  length.  Some  used  in  Belgium  were  7  j  inches 
square.  Those  used  at  Marsdeii  were  only  5  inches 
square.  At  each  end  of  the  rod  an  iron  fork  is 
clamped  and  bolted  on,  terminating  in  a  taper  male 
or  female  screw.  The  top  rod  is  connected  to  a 
strong  chain  hanging  from  one  end  of  a  huge  hori- 
zontal wooden  beam.  The  other  end  of  the  beam  is 
attached  by  a  chain  to  the  piston  of  a  vertical  steam 
cylinder.  When  steam  is  admitted  on  the  top  of 
the  piston,  the  rods  and  tool  are  raised,  but  as  soon 
as  the  engine-man  opens  the  valve  which  lets  the 
steam  escape,  the  rods  and  tool  fall  by  their  own 
weight,  and  the  rock  is  chipped  at  the  bottom  of 
the  hole.  Two  methods  have  been  employed  for 
avoiding  the  injurious  vibrations  of  the  rods  which 
would  occur  if  there  were  a  rigid  connection  be- 
tween them  and  the  tool.  One  is  a  sliding  joint 

similar  in  principle  to  that  of  Oeynhausen;  the  other  is  some 

free-falling  arrangement,   such  as  the  catch  actuated  by  a  disc, 

which  has  already  been  described  (Fig.  122). 

The  rods  are  turned  in  the  usual  way  by  a  tiller,  and  they  can 

be  lowered,  as  the  hole  is  deepened,  by  a  screw  similar  to  that  used 

in  small  borings. 

The  mud  and  fragments  produced  in  boring  are    cleared  out 

by  a  sludger ;  that  is  to  say,  a  hollow  sheet-iron  cylinder  provided 

with  "semicircular  flap-valves   at   the  bottom.      The   sludger    is 

sometimes  worked  by  the  rods  and  sometimes  by  a  rope,  which 

*  Chaudron,  "  Precede  Kind.  Travaux  executes  en  Belgique,"  Annales 
des  Mines,  c;e  Serie,  tome  xviii.  pp.  435  et  seq.  ;  Smyth,  "  On  the  Sinking  of 
Pit  Shafts  by  Boring  under  Water,  as  practised  by  Messrs.  Kind  &  Chau- 
dron," Trans.  N.  E.  Inst.  M.  Eng.,  vol.  xx.,  1871,  p.  187  ;  Bainbridge,  "On 
the  Kind-Chaudron  System  of  Sinking  Shafts  through  Water-bearing 
Strata,  without  the  Aid  of  Pumping  Machinery,"  Proc.  Inst.  C.E.,  vol. 
xxxiv.,  1871-72,  p.  43;  Daglish,  "  On^the  Sinking  of  Two  Shafts  for  the 
Whitburn  Coal  Company,"  Proc.  Inst:  C.E.,  voL  Ixxi.,  1882-83,  p.  178. 


SUPPORTING  EXCAVATIONS. 


273 


FIG. 


passes  over  a  pulley  at  the  top  of  the  boring  tower,  and  is  coiled 
on  a  drum  set  in  motion  by  a  special  steam-engine. 

When  a  small  shaft  has  been  cut  out  in  this  way,  either  for 
part  or  the  whole  of  its  depth,  the  work  of  enlarging  may  com- 
mence. The  enlarging  tool  is  a  huge  composite  borer  (Fig.  315), 
with  twenty-eight  cutting  chisels,  weighing  i6j  tons;  in  he 
centre  it  has  a  projecting  loop  of  iron  a,  which 
fits  loosely  into  the  small  shaft,  and  serves  as 
a  guide.  The  chisels  are  arranged  so  as  to 
make  a  sloping  cut,  in  order  that  the  sludge 
and  chips  may  pass  down  easily  into  the  inner 
pit. 

In  some  cases  the  ordinary  sludger  is  em- 
ployed for  clearing  out  this  hole,  but  arrange- 
ments may  be  made  for  catching  the  debris 
in  a  special  bucket,  which  is  either  placed 
at  the  bottom  of  the  hole,  or  is  hung  from  a 
little  ledge  cut  for  the  purpose.  When  it  is 
supposed  that  it  is  full,  the  boring  rods  are 
lowered  and  the  bottom  one  screwed  on  to  it. 
This  operation  might  appear  somewhat  diffi- 
cult, but  by  providing  the  female  screw  at 
the  end  of  the  bottom  rod  with  a  funnel- 
shaped  bonnet,  it  is  guided  into  its  proper 
course  over  the  male  screw  on  the  sludger 
bucket,  and  the  necessary  connection  is 
easily  made. 

The  shaft  is  thus  sunk  to  the  required 
depth,  which  must  previously  have  been 
ascertained  by  a  small  borehole.  When 
therefore  it  is  known  that  a  bed  suitable 
for  a  foundation  below  the  water-logged 
strata  has  been  reached,  a  seat  is  prepared  by  boring  very 
carefully  with  the  chisels  arranged  horizontally.  The  seat  is 
scraped  with  a  special  tool,  so  as  to  clear  off  any  stones,  and  the 
tubbing  can  now  be  lowered.  The  scraping  claws  can  also  be 
used  just  before  the  tubbing  touches  the  bottom,  as  they  will 
pass  through  the  central  equilibrium  pipe  which  will  be  de- 
scribed immediately.  The  tubbing  is  made  of  rings  of  cast-iron 
joined  by  bolts  through  theiF  internal  flanges.  A  thin  strip  of 
sheet  lead  is  put  in  the  joint  so  as  to  make  it  stanch.  The  flanges 
are  sail  faced  in  a  lathe  in  order  to  secure  not  only  a  watertight 
joint,  but  also  the  perfect  verticality  of  the  whole  column.  At  the 
very  bottom  there  are  two  rings  with  flanges  turned  outwards, 
and  the  upper  is  capable  of  sliding  down  over  the  lower.  The 
space  between  the  two  outer  flanges  is  filled  with  moss,  which  is 
further  kept  in  place  by  a  net.  Lastly,  just  above  this  moss-box, 
as  it  is  called,  a  dish-like  bottom  is  bolted  on,  carrying  a  central 

8 


274 


ORE  AND  STONE-MINING. 


pipe  which  can  be  lengthened  as  the  tubbing  descends.     The  pipe 
is  called  the  equilibrium  tube. 

The  whole  arrangement  is  best  understood  from  Fig.  316.*  B  is 
the  bottom  ring  carrying  the  moss  outside  it ;  A  is  the  ring  which 
can  slide  down  over  it  telescopically ;  G  is  the  close  bottom  of  the 
column  of  tubbing,  H  the  equilibrium  tube,  I  the  space  between 


FIGS.  316,  317  &  318. 


the  tubbing  and  the  sides  of  the  shaft.  The  column  is  lowered 
into  the  shaft  by  means  of  six  iron  rods,  to  which  lengthening- 
pieces  are  added  as  required.  The  top  part  of  each  suspend- 
ing rod  is  a  strong  screw,  13,  feet  long,  working  in  a  big 
nut  on  a  frame  above  the  shaft.  The  screwed  rod,  attached  by 
a  swivel  to  the  rod  below,  can  be  turned  round  by  a  little  winch. 
After  a  new  ring  has  been  put  on,  men  at  these  six  little  winches 
lower  the  column  slowly ;  but  the  whole  weight  of  the  column 

*  Daglish,  op.  cit. 


SUPPORTING  EXCAVATIONS.  275 

does  not  come  upon  the  screws.  The  watertight  bottom  Gr  causes 
the  tubbing  to  displace  so  much  water  in  the  shaft,  that  the  whole 
column  could  be  made  to  float  if  necessary.  Such  buoyancy  would 
be  inconvenient ;  and  it  is  desirable  that  the  column  should  be 
made  heavy  enough  to  sink  down  of  itself  when  the  screws  are 
worked.  The  necessary  excess  of  weight  is  obtained  by  tapping 
the  equilibrium  pipe,  and  allowing  a  certain  amount  of  water  to 
flow  into  the  annular  space  around  it.  The  column  weighted  in 
this  way  finally  arrives  at  the  bottom  of  the  pit,  and  the  broad 
flange  of  the  ring  B  rests  on  D  as  shown.  When  the  lowering 
is  continued,  the  ring  A  slides  down  over  B,  which  is  stationary, 
and  the  flange  C  compresses  the  moss  lying  in  the  moss-box, 
squeezes  it  outwards  against  the  sides  of  the  shaft  and  makes  a 
watertight  joint  (Fig.  317). 

The  next  operation  is  filling  up  the  annular  space  outside 
the  tubbing  with  cement  or  concrete.  The  cement  used  in  cer- 
tain cases  was  a  mixture  of  hydraulic  lime  with  sand  and  trass. 
It  is  lowered  in  special  boxes  so  constructed  that  their  contents 
can  be  discharged  when  they  have  reached  any  required  position. 
After  ample  time  for  hardening  has  been  given,  the  water  is  drawn 
out  of  the  shaft  by  a  bucket ;  the  dish-like  bottom  is  now  taken 
•off,  and  the  joint  made  by  the  moss-box  can  be  examined.  Even 
when  this  joint  seems  perfectly  good,  it  is  thought  desirable  by 
some  to  take  the  additional  precaution  of  putting  in  a  wedging 
curb  in  the  ordinary  way  a  little  below  the  moss-box  (Figs.  317 
and  318)  ;  a  few  rings  of  ordinary  segmental  tubbing  are  then 
built  up  in  the  interval.  A  careful  joint  is  made,  and  the  shaft 
is  looked  upon  as  permanently  secure. 

The  advantages  of  >the  Kind-Chaudron  process,  which  are 
enumerated  at  length  in  Sir  Warington  Smyth's  paper,  may  be 
briefly  summed  up  as  follows  :  safety,  economy  and  speed. 

During  the  last  few  years  several  modifications  of  the  original 
Kind-Chaudron  process  have  been  introduced  with  success.  At 
Gneisenau  near  Dortmund  all  tubbing  above  the  level  of  the 
water-bearing  measures  was  discarded.  A  column  of  tubbing, 
closed  at  the  top  as  well  as  at  the  bottom,  and  somewhat  longer 
than  the  height  of  the  watery  strata,  was  lowered  into  the  shaft ; 
and  in  order  to  overcome  its  buoyancy  a  sufficient  amount  of  water 
was  let  into  it  by  a  valve,  worked  by  a  rod  reaching  to  the  surface. 
When  the  moss-box  had  been  compressed  by  the  descent  of  the 
column,  cement  was  lowered,  into  the  annular  space,  along  special 
guide-ropes  extending  from  the  bottom  ring  but  one  of  the 
tubbing  to  the  top  of  the  pit.  This  plan  enabled  the  boxes  to  be 
sent  down  and  drawn  up  more  speedily  than  would  have  been  the 
case  if  they  had  been  loose.  After  allowing  sufficient  time  for  the 
complete  hardening  of  the  cement,  the  water  was  drawn  out  of 
the  pit,  and  a  regular  wedging  curb  was  put  in  above  the  column 
>of  tubbing  and  its  protecting  jacket  of  cement. 


276 


ORE  AND  STONE-MINING. 


This  method   of  doing  the  work  saved   190  yards  (174  m.)  of 
tubbing  at  the  top  of  the  pit,  and  the  gain  in  money  was  estimated 


.  At  the  present  time  the  moss-box  seems  to  be  losing  much  of 
the  prestige  which  it  formerly  possessed,  and  French  engineers 
a,re  content  to  rely  solely  upon  careful  cementing  for  a  water-tight 
joint  at  the  bottom  of  the  tubbing.  A  shaft  was  successfully 
sunk  a  few  years  ago  by  the  "  Compagnie  de  TEscarpelle  "  in  the 
North  of  France  without  using  either  moss-box,  equilibrium 


Cm. tOO        SO          0  /  2  3  <?  mrnca. 

A,  Green  clayey  marl,  very  plastic  and  impermeable  (Dieves 
vertes).  B,  Small  boring.  C,  First  ring  of  tubbing,  with  strong 
shoe,  weighing  12  tons.  D,  Second  ring  of  tubbing.  E,  Ring 
bolted  to  a  flange  of  D.  F,  False  bottom  bolted  to  E.  G,  Man- 
hole cover.  H,  Concrete.  The  rings  of  tubbing  are  joined  to 
each  other  by  sixty  bolts,  and  the  upper  and  lower  flanges  are  - 
strengthened  by  brackets  midway  between  the  holes.  These 
brackets  have  been  omitted  in  the  figure  for  the  sake  of  clearness. 

tube,  or  the  subsequent  wedging  curb  and  false  tubbing;  and 
the  Lievin  Company  in  the  same  colliery  district,  when  sinking 
two  shafts  in  1891-92,  likewise  decided  to  dispense  with  all  the  con- 
trivances peculiar  to  the  Kind-Chaudron  method.  The  process  of 
sinking  was  very  much  simplified.  They  bored  the  shaft  in  two 
operations  :  a  first  pit  2  metres  (6ft.  6in.)  in  diameter  was  carried 
down  some  ten  or  twelve  metres  beyond  the  actual  depth  required, 
and  it  was  then  enlarged  by  a  second  tool,  4*90111.  wide,  to  the  full 


SUPPORTING  EXCAVATIONS.  277 

•diameter  of  about  5111 .  (i 6ft.  5in.).  This  plan  obviated  all  difficulty 
due  to  a  tooth  dropping  from  the  large  borer ;  it  had  simply  to  be 
scraped  into  the  small  shaft  and  was  left  at  the  bottom  until  the 
completion  of  the  tubbing.  In  the  Kind-Chaudron  process  of 
boring  the  small  and  the  large  shaft  alternately,  it  would  have 
been  necessary  to  fish  up  the  tool  before  the  smaller  shaft  could 
have  been  sunk  any  farther.  On  reaching  the  required  depth 
the  teeth  of  the  large  borer  were  fixed  so  as  to  cut  a  horizontal 
.seat,  which  was  then  scraped  clean  with  an  S-like  tool  for 
the  reception  of  the  tubbing.  The  bottom  ring  was  made 
with  a  shoe  (Fig.  319),  and  was  calculated  to  leave  an  annular 
space  14  inches  (35  cm.)  wide  for  cement,  and  the  huge  column 
with  its  watertight  base  was  built  up  and  lowered  without  any 
equilibrium  tube.  It  floated  like  an  enormous  boat  and  was 
weighted  with  water  so  as  to  sink  as  required.  After  it  had 
been  very  carefully  brought  into  the  centre  of  the  pit,  the  concrete 
was  lowered  in  specially  contrived  boxes  which  deposited  it 
automatically  on  reaching  the  bottom.  The  successful  result  of 
these  sinkings  has  justified  the  procedure  of  the  Lievin  engineers  ; 
they  are  of  opinion  that,  in  any  future  sinking,  time  might  be 
saved  by  doing  the  boring  in  three  operations  instead  of  two. 

The  following  facts*  relating  to  one  of  the  pits  lately  sunk  by 
the  Lievin  Company  (No.  4  bis)  show  the  rapidity  with  which 
the  work  can  be  carried  out.  Boring  with  the  small  tool  began 
on  the  ist  of  November  1891,  and  was  stopped  on  the  i4th  of 
January  1892,  when  a  depth  of  111-71  m.  (122  yards)  had  been 
reached.  The  large  tool  was  set  to  work  on  the  i6th  of  January, 
and  by  the  7th  of  June  following  the  pit  had  been  bored  to  the 
depth  of  100  metres  (109  yards).  A  week  was  then  occupied  in 
cleaning  the  bed,  taking  down  the  boring  plant,  and  making 
preparations  for  putting  in  the  tubbing.  Beginning  on  the 
1 4th  of  June,  the  lowering  of  the  tubbing  was  finished  on  the 
2  gth;  it  took  three  days  to  get  the  column  into  position  and 
make  it  rest  properly  upon  its  seat,  and  three  weeks  to  put  in  the 
concrete.  After  spending  ten  days  in  taking  down  the  boring 
shed  and  plant,  the  engineers  were  able  to  begin  drawing  out  the 
water  on  the  2nd  of  August,  and  they  finished  on  the  7th.  The 
false  bottom  was  brought  up  on  the  8th  of  August,  and  prepara- 
tions were  at  once  made  for  continuing  the  sinking  in  the  ordinary 
way.  The  sinking  was  recommenced  on  the  3oth  of  August. 

Compressed  Air  Method. — Sinking  by  the  aid  of  compressed 
air  came  into  notice  after  a  successful  application  of  this  method 
by  M.  Triger  in  France  about  half  a  century  ago.  In  this 
method  a  cylinder  of  cast-iron,  made  up  by  adding  ring  after  ring 
at  the  surface,  like  a  column  of  Chaudron's  tubbing,  is  caused  to 
.sink  gradually  by  the  earth  in  the  bottom  being  worked  away ; 

*  Kindly  furnished  by  M.  Desailly,  the  engineer  in  charge. 


278  ORE  AND  STONE-MINING. 

and  in  order  to  prevent  the  water  in  the  surrounding  beds  from 
coming  in,  air  under  pressure  is  led  into  a  chamber  at  the 
bottom  of  the  cylinder,  which  is  shut  off  by  a  horizontal  partition 
or  diaphragm.  Above  this  working  chamber  there  is  an  "  air 
lock,"  that  is  to  say  a  closed  space  in  the  cylinder,  with  trap 
doors  above  and  below.  The  two  doors  are  never  open  at  the 
same  time.  A  man  going  down  to  his  work  passes  into  the 
middle  chamber  by  the  trap  door,  which  is  then  closed ;  the  lower 
trap  door  is  now  opened,  and  the  man  can  descend  into  the 
working  chamber.  When  he  goes  up,  or  when  the  bucket  has 
to  be  drawn  out,  there  is  always  this  break  of  the  journey,  in 
order  to  prevent  the  working  chamber  from  communicating 
directly  with  the  atmosphere.  Sinkings  by  this  process  have 
been  made  since  Triger's  time  in  various  places,  among  others  at 
Bettisfield  colliery  in  North  Wales,*  though  in  this  case  the 
arrangements  were  not  exactly  the  same  as  those  originally 
employed  in  France. 

There  are  two  great  disadvantages  coupled  with  this  method : 

(1)  The  impossibility  of  going  to  a  depth  much  exceeding  100 
feet,  because,  speaking  generally,  a  pressure  of  45  Ibs.  per  square 
inch,  or  three  atmospheres  above  the  normal  pressure  of   the 
atmosphere  is  about  as  much  as  men  can  stand. 

(2)  The  fact  that  the  health  of  the  men  has  been  found  to 
suffer  from  such  an  atmosphere.     In  all  cases  it  appears  advisable 
to  avoid  the  sudden  changes  of  pressure,  and  therefore  invariably 
to  make  a  little  stay  in  the  air-lock  before  going  up  or  down. 

Freezing  Method. — The  solidification  of  watery  strata  by  cold 
may  be  effected  naturally  or  artificially.  In  Siberia,!  when  sink- 
ing shallow  exploratory  pits  through  watery  strata  in  search  of 
auriferous  alluvia,  advantage  is  taken  by  prospecting  parties  of  the 
severe  cold  to  let  Nature  form  protecting  walls  of  frozen  ground. 

In  Western  Siberia  the  process  is  as  follows  :  Towards  the  end 
of  the  summer,  square  pits  about  6  or  7  feet  on  the  side  are  sunk 
as  deep  as  possible  without  penetrating  into  the  watery  beds. 
The  men  then  prepare  log-huts,  as  dwellings  for  the  winter,  and 
lay  in  good  stocks  of  firewood.  After  the  first  frost  the  snow  is 
cleared  out  of  the  pits,  and  also  from  off  the  ground  for  a  space 
several  yards  in  diameter  round  the  tops,  in  order  to  let  the  cold 
penetrate  more  freely.  As  soon  as  the  ground  is  thoroughly 
frozen,  the  sinking  is  begun  by  a  kind  of  fire-setting.  Billets  of 
wood  are  laid  crosswise  on  the  bottom  of  the  ground  and  lighted. 
The  fire  thaws  the  ground  for  a  short  distance,  and  the  workmen 
have  to  be  careful  that  the  heat  does  not  penetrate  too  far,  and 
so  let  in  the  water  from  the  unfrozen  strata  a  short  distance  be- 

*  Lupton,  discussion  on  Mr.  Danish's  paper,  "  On  the  Sinking  of  Two 
Shafts  at  Marsden,"  Proc.  Inst.  C.E.,  vol.  Ixxi.  1892-93,  p.  197,  with  figure. 

t  Helmhacker,  "  Ueber  das  in  Sibirien  iibliche  Abteufen  von  Schurf- 
schachten  im  schwimmenden  Gebirge,"  B.  u.  h.  Z.,  1891,  p.  88. 


SUPPORTING  EXCAVATIONS. 


279 


low  line  i,  i,  representing  the  junction  of  the  frozen  with  the 
unfrozen  ground  (Fig.  320). 

The  workmen  with  pick  and  shovel  remove  the  softened  portion 
(a),  and  so  deepen  the  shaft  by  some  4  to  6  inches.  It  is  then  left 
for  two  or  three  days  to  freeze  again,  when  the  junction  between 
frozen  and  unfrozen  ground  is  carried  to  2,  2  ;  a  second  fire 
softens  the  part  (b)  which  is  removed,  and  then  another  exposure 
to  the  frost  for  two  or  three  days  makes  the  ground  solid  to  3,  3, 
when  the  part  (c)  can  be  softened  and  taken  out. 

FIG.  320. 


The  alternate  processes  of  freezing  and  thawing  are  repeated 
every  three  or  four  days,  and  each  time  the  shaft  is  deepened 
from  4  to  8  inches.  As  the  auriferous  bed  is  approached,  samples 
are  washed  from  time  to  time  to  see  whether  there  is  any  gold, 
and  when  the  stratum  containing  the  precious  metal  is  reached 
(Fig.  321),  all  the  earth  is  carefully  washed  and  the  amount  of 
gold  noted.  Judging  by  results  of  similar  undertakings  in  the 
district,  it  is  possible  to  say  whether  or  not  it  will  pay  to  work 
the  alluvium.  In  both  figures,  A  represents  the  bed  rock,  B  the 
stratum  of  gold-bearing  gravel,  C  overlying  gravel  containing  little 
or  no  gold,  D  timbering  at  the  top.  The  hatching  denotes  ground 
that  is  frozen.  The  shafts  are  sunk  to  a  depth  of  1 6  to  26  feet. 

In  Eastern  Siberia  the  conditions  are  more  favourable  for 
this  kind  of  work,  as  the  winter  is  longer,  and  therefore  the  shafts 


28o  ORE  AND  STONE-MINING. 

can  be  sunk  deeper.  But  the  principal  advantage  lies  in  the  fact 
that  much  of  the  ground  is  eternally  frozen ;  here  the  thawing 
can  be  carried  on  without  any  stoppages,  and  less  care  is  neces- 
sary, save  when  the  underlying  unfrozen  strata  are  reached. 
These  have  to  be  treated  by  alternate  freezing  and  thawing  as  in 
Western  Siberia.  As  a  rule,  however,  the  ground  is  eternally 
frozen  for  the  whole  thickness  of  the  alluvium  clown  to  the  bed 

FIG.  321. 


-'oJ?      -    ** 

,    - •    ---•     :_       j-    7-I-.J-I  1     :_ '  *"P    -    — 

*    *    *„     >    ^     o        «•-+»   -j»  —--r  !<»•.•       <»'<>    j    °   ^%    a 

^••^AW'fy^ 

A 

rock.     Exploratory  pits  are  sunk  in  Eastern  Siberia  to  a  depth 
of  85  feet  (26  m.)  by  this  method. 

Shafts  are  even  put  down  in  shallow  rivers  to  see  whether  their 
beds  are  gold-bearing.  In  autumn,  when  the  water  is  shallow,  a 
set  of  frames,  like  shaft  frames,  6  or  7  feet  square,  is  lowered  till 
it  touches  the  bottom,  whilst  the  top  is  above  the  level  of  the 
stream.  It  is  filled  up  with  stones,  and  loose  stones  are  placed 
around  it.  When  winter  sets  in,  the  river  freezes,  and  the  con- 
tents of  the  box  gradually  become  hard.  A  first  layer  of  stones 
is  then  worked  out  with  the  pick,  and  the  frost  allowed  to  pene- 
trate downwards.  Another  layer  of  stones  is  taken  out,  and 
again  there  is  an  interval  for  freezing.  By  repeating  this  pro- 
cess the  contents  of  the  box  are  removed  little  by  little,  and  at 
last  the  river  bed  is  reached  and  allowed  to  become  hard  and 
solid  from  the  cold,  whilst  at  the  same  time  the  water  in  the 
interstices  between  the  outer  stones  has  been  congealed,  and  has 


SUPPORTING  EXCAVATIONS.  281 

formed  strong  protecting  walls  of  icy  conglomerate.  Further 
sinking  is  now  carried  on  as  in  Western  Siberia. 

In  some  cases  the  wooden  box  is  dispensed  with,  and  when 
the  river  is  covered  with  a  thick  coat  of  ice,  the  prospector  cuts 
out  a  space  a  few  inches  deep  of  the  size  of  the  shaft.  The 
removal  of  a  part  of  the  ice  at  the  top  allows  the  cold  to  be 
felt  further  down,  and  the  ice  becomes  thicker  underneath. 
Another  slice  is  taken  off  the  top  and  again  the  cold  penetrates 
further,  arid  in  proportion  as  the  top  is  removed  the  bottom  re- 
ceives coat  after  coat  of  new  ice.  By  successive  thickenings  the 
ice  finally  reaches  the  river  bed,  and  the  prospector  can  then  pro- 
ceed by  the  West  Siberian  method. 

Poetsch's  artificial  freezing  process  consists  in  causing  a  very 
cold  liquid  to  circulate  in  pipes  through  the  ground,  and  so  con- 
vert it  into  a  solid  mass,  in  which  an  excavation  can  be  made 
without  timber  or  other  supports.  While  the  ground  is  kept 
frozen  some  form  of  watertight  lining  is  put  in,  sufficiently  stanch 
to  keep  out  the  water  when  the  cold-producing  appliances  are 
removed. 

Poetsch  employs  a  Carre  machine  for  generating  cold.  Anhy- 
drous ammonia  gas  is  liquefied  by  compression  in  suitable  pumps, 
and  the  liquid  which  leaves  at  a  temperature  of  102°  F.  (38°  C.)  is 
cooled  by  passing  it  through  pipes  surrounded  by  cold  water. 
The  cold  liquid  ammonia  is  then  made  to  flow  into  a  long  series 
of  pipes,  placed  in  a  large  wooden  tank  containing  a  solution  of 
chloride  of  calcium.  The  liquid  ammonia  expands  into  gas  in 
these  pipes,  and  extracts  heat  from  the  solution  surrounding  them 
to  such  an  extent  that  the  temperature  of  the  contents  of  the 
tank  is  brought  down  to  8°  or  9°  F.  (  -  13°  C.)  The  ammonia  gas 
is  returned  to  the  compressor  to  be  again  liquefied  and  utilised 
for  the  production  of  cold. 

The  refrigerating  solution  of  chloride  of  calcium  is  pumped 
from  the  tanks  into  a  main,  which  leads  it  to  a  series  of  pipes, 
placed  in  boreholes  arranged  in  a  circle  around  the  top  of  the 
proposed  shaft.  The  pipes  are  double,  that  is  to  say,  there  is 
an  inner  small  pipe  i  J  or  2  inches  in  diameter  for  the  down- 
ward journey  of  the  cold  solution,  and  an  outer  one  4^  to  7 
inches  in  diameter,  carefully  closed  at  the  bottom,  by  which  the 
solution  ascends  and  does  its  cooling  work  on  the  way.  When  it- 
reaches  the  surface  it  returns  to  the  cooling  tank,  and  is  again 
refrigerated.  The  process  is,  therefore,  continuous,  the  ammonia 
and  the  chloride  being  used  over  and  over  again.  The  nature  of 
the  freezing-tube  will  be  evident  from  Fig.  322  * ;  a  is  the  large 
outer  pipe  connected  to  another,  m,  by  the  piece,/;  n  is  a  small 

*  Poetsch,  "Ueber  die  verbesserte  Ausfuhrung  des  Gefrierverfahrens 
beim  Schachtabteuf en  und  Streckenbetrieb,"  Der  iv.  allyemeine  Bergmanns- 
tag  in  Halle  [Saale].  Fesibcriclit  und  Verliandlungen.  Halle,  1890,  p.  119, 
and  Plate  x. 


282 


ORE  AND  STONE-MINING. 


inner  pipe,  and  the  arrows  show  the  course  of  the  solution.      The 
supply  of  chloride  is  taken  from  a  circular  pipe  at  the  top,  fed 


FIG.  323. 


from  the  main,  and  in  like  manner  the  solution  ascending  the 
various  pipes  is  collected  by  another  ring  and  led  back  to  the 
cooler.  The  particular  pipe  shown  in  the  figure  is  destined  for 
the  case  of  a  sinking,  in  which  the  upper  part,  m,  is  in  strata  that 


SUPPORTING  EXCAVATIONS.  283 

do  not  need  to  be  frozen.  The  letter  p  represents  a  jacket  made 
of  some  bad  conductor,  to  prevent  the  solution  from  becoming 
warmed  unnecessarily  in  its  ascent. 

In  sinking  through  ground  consisting  of  watery  strata  alternat- 
ing with  dry  measures,  Poetsch  advises  the  following  method 
of  procedure.  A  (Fig,  323)  represents  dry  ground  through  which 
the  shaft  has  been  sunk  and  timbered  in  the  ordinary  way; 
B  indicates  watery  beds  where  tubbing  is  necessary.  Poetsch  puts 
in  first  of  all  a  circle  of  holes,  a  a,  round  the  outside  of  the  shaft, 
and  a  smaller  circle  b  b,  around  the  inside.  When  these  latter  have 
frozen  the  ground  adjacent  to  them,  the  still  smaller  circle  of  holes 
b  b,  are  bored  and  fitted  with  refrigerating  tubes ;  as  soon  as 
the  ground  about  them  has  become  converted  into  a  solid  pro- 
tecting wall,  the  shaft  is  sunk  with  a  reduced  diameter,  until  the 
dry  strata,  C,  are  pierced.  On  reaching  ground  suitable  for  the 
wedging  curb,  the  tubbing  is  built  up  in  the  ordinary  way;  the 
parts  b  b  are  cut  away,  and  by  this  time  the  freezing  has  become 
so  complete  at  a  that  there  is  no  danger  of  the  walls  falling  in. 

In  this  process  there  is  a  risk  of  failure,  or  at  all  events  of 
trouble,  if  there  is  any  escape  of  the  freezing  solution  from  the 
pipes,  because  the  ground  impregnated  with  it  would  be  uncon- 
gealable.  Gobert  proposes  to  overcome  this  difficulty,  and  at  the 
same  time  to  make  the  method  more  economical,  by  sending 
down  anhydrous,  or  all  but  anhydrous,  ammonia,  and  allowing 
it  to  vaporise  in  the  tubes,  instead  of  circulating  a  refrigerating 
solution,  Intense  cold  is  thus  produced  at  the  very  point  where 
it  is  required,  and  the  ground  is  frozen.  The  ammonia  gas  is 
drawn  out  by  a  pump,  and  after  having  been  reliquefied  by  pressure 
is  used  over  again.  Gobert  claims  for  this  process  that  both  the 
original  outlay  for  plant,  and  the  subsequent  running  expenses,  are 
considerably  reduced.  He  has  also  been  led  by  his  experience  to 
introduce  improvements  in  the  joints  of  the  freezing  pipes,  with 
the  object  of  ensuring  absolute  freedom  from  leakage,  and  of 
making  the  line  of  pipes  quite  flush  outside,  so  as  to  facilitate  their 
withdrawal  at  the  end  of  the  sinking. 

II  has  been  proposed*  to  inject  powdered  cement,  by  means  of 
compressed  air  or  steam,  into  watery  strata,  and  so  consolidate 
them  sufficiently  to  render  the  sinking  of  a  shaft  a  matter  of  no 
great  difficulty. 

The  Haase  Process,!  for  sinking  through  quicksands,  consists 
in  forcing  down  a  set  of  wrought-iron  tubes  around  a  circular 
or  rectangular  area  destined  for  the  shaft.  The  narrow  inter- 
spaces between  the  tubes  are  closed  by  angle-iron  and  T-iron 
riveted  on  longitudinally,  which  form  a  joint  permitting  vertical 
motion  and  stanch  enough  for  the  work  in  question.  Water  forced 

*   Colliery  Guardian,  vol.  Ixi.  1891,  p.  1089. 

t  Zeitschr.  f.  B.-  H.-  u,  /SI-  Wesen,  vol.  xxxvii.  1889,  p.  204. 


284  ORE  AND  STONE-MINING. 

down  a  hollow  boring  rod  in  the  middle  of  each  tube  loosens  the 
sand  and  carries  it  up  to  the  surface.  The  tube  can  then  be 
driven  down  by  a  screw-jack  or  an  hydraulic  press.  The  tubes 
are  carefully  guided  in  order  to  ensure  a  strictly  vertical  path ; 
and  as  soon  as  they  have  been  forced  down  into  hard  or  compara- 
tively hard  rock,  the  quicksand  can  be  excavated,  for  the  iron 
lining  prevents  any  influx  from  the  outside. 

Instead  of  iron  tubes,  Haeuser*  employs  sheets  of  corrugated 
iron,  with  tongues  riveted  on  so  that  the  bottom  of  each  sheet 
is  held  by  the  top  of  the  one  below.  Like  the  Haase  tubes,  the 
sheets  are  forced  down  with  a  strong  screw-jack.  Another  plan 
adopted  by  Haeuser  consists  in  making  the  protecting  shield  of 
pieces  of  flat  iron  6  inches  wide ;  each  "  lath,"  if  it  may  be  so 
called,  is  connected  to  its  neighbour  by  a  longitudinal  groove 
formed  by  riveting -on  two  strips  of  iron. 

*  Herold,  "  Das  Schacht-Abteufen  im  schwimmenden  Gebirge  mit  Haase' 
schem  und  Haeuser'  schem  Verfahren  beim  Braunkohlenwerk  '  Zwenkau  '  in 
Zwenkau,"  Jahrb.f.  d.  B.-  und  If.-  Wesen  i.  K.  Sacksen,  1891,  p.  27. 


CHAPTER     VI. 
EXPLOITATION. 

Classification  of  methods  of  working — (i)  Open  works  of  all  kinds, 
including  hydraulic  mining.  (2)  Excavation  of  minerals  under  water. 
(3)  Extraction  of  minerals  by  wells  or  bore-holes.  (4)  Underground 
workings. 

THE  methods  of  working  mineral  deposits  may  be  naturally 
arranged  into  two  great  classes — viz.,  open  works,  in  which  the  ex- 
cavation is  open  to  the  sky ;  and  underground  works,  in  which  the 
miners  perform  their  labour  in  chambers  or  passages  under  a  cover 
of  rock  or  earth,  and  in  which  they  usually  need  artificial  light. 
But  there  are  in  addition  two  other  classes  of  workings,  used  in 
comparatively  exceptional  cases,  which  require  a  place  in  any  com- 
plete classification.  Gold-bearing  gravel  and  phosphates  are  occa- 
sionally dredged  up  from  river-bottoms ;  and  liquid,  gaseous,  or 
soluble  minerals  can  be  got  by  wells  or  bore- holes.  Consequently 
it  is  necessary  to  subdivide  the  subject  into  four  heads : 

1.  Open  works  of  all  kinds,  including  hydraulic  mining. 

2.  Excavation  of  minerals  under  water. 

3.  Extraction  of  minerals  by  wells  or  boreholes, 

4.  Underground  workings. 

OPEN  WORKS. — Some  minerals  are  always  obtained  in  this 
way  ;  others  are  worked  open  before  regular  underground  mining 
begins ;  and,  thirdly,  it  often  happens  that  underground  and 
surface  workings  are  both  being  carried  on  simultaneously  in  adja- 
cent parts  of  the  same  mine.  Among  the  minerals  worked  open- 
cast are  the  ores  of  copper,  gold,  iron,  lead  and  tin,  to  say  nothing 
of  all  sorts  of  stone. 

The  advantages  of  open  works  may  be  summed  up  as  follows : 

(a)  Complete  removal  of  the  mineral  without  any  loss  in  the  form  of 

pillars. 
(&)  No  expense  or  trouble  as  regards  ventilation,  men  always  working 

in  good  air  ;  no  danger  of  explosions. 

(c)  No  expense  for  lighting,  unless  work  is  carried  on  at  night. 

(d)  No  expense  for  timbering. 

(e)  Possibility  of  laying  out  the  work  in  larger  steps  or  stopes  than 

can  usually  be  done  in  underground  working  places. 
(/)  Easier  supervision. 


286  ORE  AND  STONE-MINING. 

On  the  other  hand,  there  is  usually  the  immense  disadvantage 
of  it  being  necessary  to  remove  a  great  deal  of  waste  rock  covering 
the  deposit,  technically  known  as  overburden.  Work  too  may 
be  stopped  by  bad  weather,  such  as  heavy  rain  or  snow ;  open 
quarrying  may  spoil  land  or  interfere  with  roads  or  canals,  so  that 
the  benefits  do  not  all  lie  with  the  open  works.  The  cryolite  of 
Greenland*  is  worked  opencast  from  April  to  December,  and  dur- 
ing the  rest  of  the  year  the  miners  are  employed  below-ground. 

One  of  the  simplest  cases  of  working  away  a  mineral  is  that  of 
borax  in  California.  The  efflorescence  has  merely  to  be  swept  into 
wind-rows  and  carted  away  to  the  refining  works. 

The  beds  of  nitrate  of  soda  in  Chili  are  worked  by  large  blasts 
as  shown  in  Fig.  54.!  A  small  shaft  is  sunk  a  little  below  the 
bottom  of  the  "  caliche  "  and  enlarged  in  order  to  receive  a  charge 
of  slow  burning  powder  made  on  the  works.  The  explosion 
loosens  and  breaks  up  the  ground  over  an  area  about  twenty  yards 
in  diameter.  The  hard  overlying  stratum  of  "  costra "  is  then 
•easily  removed,  and  the  "  caliche  "  is  broken  up  into  lumps,  which 
are  taken  to  the  lixiviating  and  crystallising  works. 

Generally  the  first  process  in  an  open  working  is  the  removal 
of  the  overburden,  and  the  manner  in  which  this  is  done  depends 
upon  the  nature  of  the  ground. 

A  first  example  may  be  taken  from  Northamptonshire,  where  very 
large  quantities  of  iron  ore  are  obtained  from  beds  of  Jurassic  age. 
.Similar  beds  are  also  worked  in  the  counties  of  Lincoln  and  Oxford. 

The  actual  bed  of  ore  at  Cranford  in  Northamptonshire  is  from 
8  to  12  feet  thick,  and  the  amount  of  overburden  taken  off  is 
sometimes  as  much  as  20  feet ;  when  this  thickness  is  exceeded  the 
ore  can  no  longer  be  worked  with  profit. 

The  soil  or  "  meat  earth,"  which  is  from  8  inches  to  2  feet  deep, 
is  put  aside  carefully,  for  it  has  to  be  restored  to  make  the  surface 
good  and  available  for  tillage.  The  remainder  of  the  overburden  is 
•cut  away  in  one  or  more  steps  or  "  stopes,"  for  the  convenience  and 
safety  of  the  workmen,  the  base  of  any  step  being  usually  about 
equal  to  its  height.  The  accompanying  figure  (324)  represents 
a  pit  at  Kettering  in  Northamptonshire,  in  1889,  where  15  feet  of 
overburden  were  being  removed  from  a  12 -feet  bed  of  ironstone. 
The  soil  having  been  cleared  off  with  the  shovel,  the  men  undercut 
the  first  stratum  with  a  double-pointed  pick  at  a  and  then  drive 
down  a  crowbar  at  b  and  another  at  a  little  distance  from  it.  By 
working  the  bars  backwards  and  forwards  they  cause  a  big  block 
to  break  off  along  the  dotted  line.  This  crumbles  in  its  fall,  is 
shovelled  into  barrows,  wheeled  across  the  planks,  and  tipped  on  to 

*  "  Die  Kryolitverarbeitung  in  der  Eresundschen  Fabrik  in  Kopenhagen," 
B.  u.  h.  Z.,  1893,  p.  69. 

f  Robert  Harvey,  "Machinery  for  the  Manufacture  of  Nitrate  of  Soda  at 
the  'Ramirez'  factory,  Northern  Chili,"  Proc.  Inst.  Civ.  Eny.,  vol.  Ixxxii, 
1884-85,  p.  341. 


EXPLOITATION. 


287 


the  bank.   After  the  top  has  been  cleared  away  for  a  few  feet,  the 
next  bed  is  treated  in  the  same  way,  and  then  the  third,  until  the 


ironstone  is  reached,  and  laid  quite  bare.  The  ore  can  usually  be 
easily  broken  with  the  pick  and  at  once  loaded  into  small  waggons, 
holding  about  a  ton  each.  Occasionally  a  shot  is  fired,  in  order 


288 


ORE  AND  STONE-MINING. 


to  loosen  parts  that  are  hard.  The  loading  is  done  with  an  eight- 
proiiged  fork,  so  as  to  separate  the  fine  ore  which  the  smelters 
refuse  to  take.  If  there  is  much  fine,  the  ore  is  sifted  ;  one  man 
stands  over  a  wheel-barrow  holding  a  round  sieve,  with  a  half- 
inch  mesh,  and  another  shovels  the  ore  to  him.  The  fine  drops 
into  the  barrow  and  can  be  wheeled  away,  while  the  coarse  is 
thrown  into  the  waggon.  The  men  working  on  the  overburden 
are  paid  per  cubic  yard,  and  those  excavating  ore  are  paid  per  ton 
of  ore  placed  in  the  trucks. 

The  working  faces  are  long,  in  order  that  a  large  number  of 
men  may  be  employed  at  one  time.  As  surface  rent  must  be  paid 
whilst  the  ground  is  useless,  the  soil  is  put  back  with  the  least 
possible  delay,  and  tillage  then  goes  on  once  more  upon  fields  which 
have  been  lowered  several  feet.  In  the  figure  a  small  waggon  is 


FIG.  325. 


FIG.  326. 


shown,  but  in  some  of  the  pits  a  full-sized  railway  waggon  is 
brought  into  the  cutting  and  loaded  directly  with  8  or  10  tons  of 
ironstone.  When  a  slice  10  or  12  feet  wide  has  been  removed  all 
along  the  face,  the  rails  are  shifted  and  a  fresh  cut  taken. 

The  workings  start;  for  instance,  from  some  convenient  point,  C 
(Fig.  325),  connected  to  a  main  railway  or  wharf  at  X,  and  the  first 
line  of  workings  is  supposed  to  be  shown  by  CD,  reaching  to  the 
boundary  of  the  property  AB.  The  successive  positions  of  the 
working  faces  take  such  lines  as  CE,  CF,  &c.,  radiating  out  from  C 
as  a  centre,  and  all  the  ground  CDK  may  have  been  given  back  to 
the  farmer,  before  the  working  face  has  assumed  the  position  OP. 

In  hard  rocks  the  steps  may  be  made  very  much  higher.  Thus, 
at  the  great  Penrhyn  slate  quarry,  near  Bangor,  in  North  Wales, 
the  valuable  slate  and  the  valueless  overburden  are  both  taken 
away  by  a  series  of  terraces  on  an  average  60  feet  high  by  30  feet 
wide,  as  shown  in  Fig.  326. 

The  great  opencast  at  Rio  Tinto  (Fig.  327)  is  a  huge  open  pit 


EXPLOITATION. 


289 


from  which  the  ore  is  got  by  a  succession  of  stopes,  benches  or 
terraces,  33  feet  to  50  feet  high.  The  pit  is  oval  in  shape,  and 
650  yards  (600  m.)  in  length  on  the  top  of  the  ore. 

FIG.  327. 


A,  cupreous  pyrites  ;  B,  slate  ;  C,  porphyry. 

The  opencast  at  the  Mechernich  lead  mine  is  also  worked  in  a 
similar  manner.  The  Government  regulations  make  it  necessary 
that  the  base  of  each  step  shall  be  at  least  10  feet  wide,  so  that. 


FIG.  328. 


stuff  may  not  roll  down  from  one  floor  on  to  the  men  working 
below.  The  actual  width  is  very  much  more,  being  usually  26  feet 
(8  m.),  whilst  the  height  is  33  feet  (10  m.) 

When  the  rock  is  firm  enough  to  stand  for  a  great  height,  it  is 
sometimes  found  convenient  to  take  it  down  in  one  vertical  slice 

T 


290  ORE  AND  STONE-MINING. 

without  making  a  series  of  steps.  The  general  appearance  of 
Mulberry  mine,*  near  Bodmin  in  Cornwall,  which  is  worked  in  this 
manner,  will  be  understood  by  a  reference  to  Fig.  328.  Men 
standing  at  A  bore  and  blast  holes,  which  throw  the  rock  to  B, 
under  which  a  level  has  been  driven  with  an  opening  C,  usually 
closed  by  a  covering  of  timber.  A  waggon  is  run  in  under  this 
opening  and  is  easily  filled. 

Another  method  is  that  of  firing  a  very  large  blast,    which 
brings  down  thousands  of  tons  of  rock  at  a  time.    It  is  prepared  by 

FIG.  329. 


Xte^y  i 

it '  ,-si  ir"  /  . 


SCALE.  ' 


p££T   10     0  '80  200  FEET 

ME.TRES  10         o         w        20       30       AO        so       &o        70       80  MEITRE.S 

ABC,  Outline  of  the  face  of  the  quarry  before  the  blast ; 
AB'C',  Outline  after  the  blast. 

driving  in  a  tunnel  at  right  angles  to  the  face  of  the  quarry  and 
making  one  or  more  chambers,  which  are  charged  with  gunpowder 
or  some  other  explosive ;  the  tunnel  is  tamped  up  like  a  gigantic 
shothole,  and  the  charge  is  fired  by  a  fuse  or  by  electricity. 

As  an  example  of  a  blast  of  this  kind,  I  take  some  workings 
for  building  stone  near  Messina  (Fig.  329)^  A  tunnel  was  driven 
into  the  face  of  the  limestone  quarry  for  a  distance  of  56  feet 
(i7m.),  and  then  turned  off  at  a  right  angle.  The  chamber 

*  C.  LeNeve  Foster,  "On  Some  Tin  Stockworks  in  Cornwall,"  Quart. 
Jour.  Geol.  8oc.,  vol.  xxxiv.  1878,  p.  655. 

t  Falangola,  "  Sulle  grandi  mine  nella  roccia  calcarea  della  catena 
Peloritana  (Sicilia)  e  nella  roccia  granitica  di  Baveno  (Lago  Maggiore)/' 
Sivista  di  Artiglieria  e  Genio,  vol.  iv.  1887,  p.  343. 


EXPLOITATION. 


291 


60  formed  was  lined  with  a  quick-setting  cement  in  order  to  keep 
out  any  moisture,  and  a  cubical  wooden  box  was  built  up  inside  and 
charged  with  64.  bags  of  gunpowder,  or  in  all  31  cwt.  (1600  kil.) 

Four  ordinary  fuses,  placed  in  a  long  box  with  sawdust, 
furnished  the  means  of  firing  the  charge.  The  tunnel  was  then 
filled  up  in  the  manner  shown  in  Figs.  330  and  331.  The  object 
of  the  slightly  sinuous  form  of  the  tunnel  was  to  increase  the 
resistance  of  the  tamping. 

The  effect  of  the  large  blast  was  to  break  up  and  move  more 
rthan  100,000  cubic  yards  (80,000  c.m.)  of  rock,  with  the  advantage 


FIGS.  330  &  331. 

DETAILS    OF  THE  TUNNEL. 
PLAN. 


.i,so^ 
C   \ 


SECTION    ALONG  THE    LINES    AB.  BC. 


1.50 


«,  damp  earth  beaten  in  ;  &,  brick  wall  built  with  common  mortar  ; 
c,  dry  stone  wall  ;  d,  wall  built  with  a  quick-setting  cement  ; 
e,  wall  built  with  hydraulic  lime  ;  dimensions  in  metres. 

of  producing  less  small  stone  than  would  have  been  the  case  if  the 
ordinary  method  of  quarrying  had  been  employed.  The  dotted 
line  A  B'  C'  shows  the  outline  of  the  face  after  the  explosion. 

We  now  come  to  an  important  class  of  workings,  namely,  recent 
alluvial  beds,  such  as  river  gravel  containing  diamonds,  gold  or  tin 
ore.  The  banks  may  be  left  high  and  dry  when  the  river  is  low,  or 
the  stream  may  be  diverted  and  any  pools  drained  by  some  simple 
pump.  The  whole  process  of  working  often  consists  merely  in  dig- 
ging up  the  earth  with  pick  and  shovel,  and  washing  it  on  the  spot 
with  a  pan  or  batea.  If  there  is  not  enough  fall  for  discharging  the 
refuse,  in  places  where  the  operations  are  on  a  large  scale,  it 
becomes  necessary  to  raise  the  earth  by  some  appliance,  such  as 
the  hydraulic  elevator  (Fig.  345).* 

*  Kickard,  "Alluvial  Mining  in  Otago,"  Trans.  Amer.  Inst.  M.  E.. 
vol.  xxi.  1892,  p.  445. 


292 


ORE  AND  STONE-MINING. 


Dams  for  diverting  rivers  are  sometimes  of  considerable  size. 
For  instance,  on  the  Feather  river,  in  California,  there  is  a  darn 
80  feet  wide  and  50  feet  high.  The  water  is  carried  off  in  a 
"  flume"  or  launder,  50  feet  wide  and  6  feet  high. 

The  sand  of  beaches  is  occasionally  scraped  up  at  low  tide  and 
washed  for  gold  or  tin  ore. 

Hydraulic  Mining. — Under  this  head  it  is  convenient  to 
include  all  methods  of  working  in  which  water  is  used  for  breaking 
away  the  ground,  and  not  to  restrict  the  term,  as  is  most 
commonly  done,  to  the  process  of  working  auriferous  gravel  by  a 
jet  of  water  under  considerable  pressure. 

I  will  take  some  examples  : 

i.  China  Clay  Workings  in  Cornwall* — The  first  operation  is 
the  removal  of  the  overburden,  and  a  small  shaft  is  then  sunk  in 


FIG.  332, 


A,  undecomposed  granite  ;  B,  decomposed  granite  ;  C,  overburden  ; 
D,  engine-house ;  EE,  EE,  successive  outlines  of  the  open  pit ; 
aa,  shaft ;  bb,  level ;  d,  top  of  upright  launder  placed  in  the 
small  shaft  sunk  in  the  middle  of  the  decomposed  granite  ; 
ee,  column  of  pumps  through  which  the  milky  stream  of  china 
clay  and  mica  is  lifted  to  the  launder,  /. 

the  middle  of  the  area  to  be  worked  ;  the  bottom  is  put  into  com- 
munication with  the  surface  either  by  an  adit  level,  if  the  contour 
of  the  ground  is  favourable,  or  by  a  tunnel  and  shaft  (Fig. 
332),  if  the  contour  of  the  surface  does  not  permit  the  driving 
of  an  adit  save  at  a  prohibitory  cost,  or  if  it  is  more  convenient 
to  have  the  settling  pits  close  by.  The  shaft  has  to  be  fitted 
with  pumps.  A  stream  of  water  is  led  on  to  the  decomposed 
granite,  which  the  workman  loosens  with  a  heavy  pick;  the 
disintegrated  particles  are  carried  away  in  suspension  to  a  first 
settling  pit.  where  the  coarse  grains  of  quartz  are  deposited,  and 

*  Collins,  The  Hensbarrow  Granite  District,  Truro,  1878,  p.  17. 


EXPLOITATION.  293 

the  milky  stream  then  falls  down  the  launder  d,  into  the  level 
and  either  runs  out  naturally  or  is  pumped  up  to  the  surface.  It 
passes  on  to  other  settling  pits,  and  deposits  first  the  mica  and 
then  the  very  finely  divided  kaolin. 

2.  Auriferous  Gravel — The  process  known  as  "booming,"* 
practised  in  California,  Colorado,  Idaho  and  Montana,  consists  in 
discharging  the  contents  of  a  reservoir  all  at  once  on  to  beds  of 
auriferous  gravel.  The  powerful  stream  carries  away  the  stones 
and  dirt  into  wooden  troughs  or  launders,  called  "  sluices,"  and 
leaves  behind  the  gold  on  the  bed-rock,  or  in  the  upper  part 
of  the  run  of  sluices.  In  Peru  f  a  similar  process  is  adopted. 

By  a  natural  transition  from  "booming,"  we  come  to 
41  hydraulicking,"  |  a  process  in  which  a  jet  of  water  under 
pressure  is  made  to  play  against  a  bank  of  auriferous  gravel,  break 
it  down,  disintegrate  it,  and  wash  it  into  wooden  troughs,  arranged 
so  as  to  catch  the  gold  by  means  of  mercury  on  special  floors,  and 
at  the  same  time  to  discharge  the  stones,  sand  and  mud. 

For  the  purpose  of  storing  a  proper  supply  of  water,  large 
reservoirs  have  to  be  constructed,  sufficiently  high  above  the  gravel 
bank  to  secure  the  necessary  amount  of  pressure.  They  are 
formed  by  erecting  dams  across  the  valleys,  and  they  are  made 
either  of  earth,  cribs  of  timber,  or  dry  rubble  masonry.  One  of 
the  largest  in  California  is  the  Bowman  reservoir,  with  a  high 
water  area  of  500  acres  and  a  dam  100  feet  high,  which  cost 
$151,521,  or  speaking  roughly  ^30,000. 

The  water  is  taken  to  the  place  where  it  is  required  by  (i) 
ditches  ("  leats,"  Eng.) ;  (2)  flumes;  or  (3)  pipes,  (i)  The  ditches 
are  cut  out  on  the  sides  of  the  hills,  and  the  earth  thrown  out 
serves  to  strengthen  the  lower  bank.  The  shape  most  commonly 
.adopted  for  the  ditches  is  a  half -hexagon,  or  the  upbank  may  be 
made  with  an  angle  of  60°  and  the  lower  with  65°.  The  gradient 
or  "  grade  "  varies  according  to  circumstances  from  7  to  20  feet 
per  mile. 

(2)  Flumes  are  merely  wooden  troughs,  or  "launders,"  as  we 
should  call  them  in  England.  Figs.  3334!  and  334  §  show  the 
manner  in  which  they  are  usually  made  and  supported.  In  valleys 
or  canons  with  very  precipitous  sides,  the  flume  is  sometimes  car- 
ried by  iron  brackets  let  into  holes  bored  in  the  rock  and  hung  by 

*  California  State  Mining  Bureau,  Ninth  Annual  Report  of  the  State 
Mineralogist  for  the  year  ending  December  i,  1889,  p.  122,  Sacramento  1890. 
Bowie,  A  Practical  Treatise  on  Hydraulic  Mininq  in  California,  New  York. 
1885,  p.  81. 

t  Kohlmorgen,  "Die  Goldgruben  von  Carabaya  in  Peru,"  B.  u.  h. 
Zeitung,  1890,  p.  303. 

£  This  account  of  "  hydraulicking"  is  in  the  main  based,  by  permission, 
on  Bowie's  Practical  Treatise  on  Hydraulic  Mining  in  California,  New  York, 
1885. 

§  Taliesin  Evans,  "Hydraulic  Mining  in  California,"  The  Century 
Magazine,  vol.  xxv.  1883,  p.  332. 


294 


ORE  AND  STONE-MINING. 


FIG.  333. 


iron  rods  (Fig.  335).*  Where  it  is- 
possible,  ditches  should  be  put  in 
instead  of  flumes,  because  the  latter 
cost  more  for  maintenance.  They 
also  suffer  more  from  wind,  snow  and 
storms,  and  lastly  they  are  liable  to 
destruction  from  fire.  On  the  other 
hand,  it  may  be  impossible  in  some 
cases  to  put  in  ditches,  or  the  ground 
may  be  too  hard  and  too  porous  to 
make  a  ditch  advisable.  When 
water  is  scarce,  the  loss  by  soakage- 
and  evaporation  is  a  matter  of  im- 
portance. 

(3)  The  third  method  of  conveying 
water  is  by  iron  or  steel  pipes.  They 
are  useful  in  crossing  a  deep,  valley, 
for  they  save  the  expense  of  con- 

FIG.  334- 


structing  a  very  long  ditch  round  its  head,  or  a  very  high  trestle 
bridge  across  it.     Pipes  crossing  deep  valleys  are  called  "  inverted 

*  Bowie,  op.  cit. 


EXPLOITATION. 


295 


siphons,"  although  the  principle  of  the  siphon  in  no  way  comes  into 
play. 

The  pipes  are  made  of  riveted  iron  or  steel,  and  one  form  of 

FIG.  335- 


joint  is  shown  in  Fig.  336,*  made  tight  by  running  in  lead  and 
caulking  it.      The  riveting  may  be  straight  or  spiral.    To  prevent 
rusting,  the  pipes  are  coated  externally  and  internally  with   a 
mixture  of  coal-tar  and  bitumen.     Some  of  the  pipes  used  for 
conveying  water  in  this  way  are  20  or  even  30  inches  in  diameter, 
and  in  such  cases  the  thick- 
ness of  the  iron  is  from  No.  FIG.  336. 
1 6  to  No.  i4B.W.G. 

Whether  brought  by 
ditch,  flume  or  pipe,  the 
water  is  led  to  the  so-called 
"pressure-box"  or  "bulk- 
head" (Figs.  337,338,  and 
339!),  a  cistern  situated  at 
a  sufficient  elevation  to  give 
the  jet  the  force  it  requires. 
The  cistern  is  strongly  made, 
and  has  a  grating  A  to 
catch  floating  sticks  which 
might  otherwise  choke  the  pipe.  At  the  bottom  there  is  a  recep- 
tacle B  to  receive  gravel  and  sand,  which  are  discharged  from 
time  to  time  by  opening  a  hatch  at  C. 

The  pipe  leading  away  from  the  pressure-box  is  similar  to  that 
used  for  crossing  valleys,  and  it  is  brought  down  into  the 
workings ;  if  it  is  advisable  to  attack  the  bank  in  two  places  at 
once,  the  pipe  is  forked,  each  branch  having  its  valve.  The  pipe 
terminates  in  a  nozzle  from  5  to  9  inches  in  diameter  known  as  a 


is  a  wrought-iron  collar ;  &,  the  lead  5 
c,  a  nipple  of  sheet-iron  riveted  to  one 
end  of  the  pipe  d,  each  length  having 
a  similar  nipple. 


Bowie,  op.  cit. 


t  Bowie,  op.  cit. 


296 


OKE  AND  STONE-MINING. 


"  monitor."  The  monitor  shown  in  Fig.  340  *  is  provided  with  an 
arrangement  by  means  of  which  one  man  can  deflect  it  with 
great  ease.  If  the  nozzle  B  is  in  a  straight  line  with  A,  the 
stream  passes  through  it  unimpeded ;  when  it  becomes  necessary 


FIG.  337. 


FIG.  339. 


FIG.  340. 


to  turn  the  water  on  to  another  part  of  the  gravel  bank,  the  lever 
C  is  held  to  the  side  to  which  the  jet  has  to  be  deflected.  The 
pressure  of  the  water  in  B  then  moves  the  monitor  as 
desired. 

The  manner  of  using  the  powerful  jet  of  water  to  wash  down 
banks  of  gravel  is  well  depicted  in  Fig.  341,  borrowed  from  Mr. 
Evans'  interesting  article. 

If  the  gravel  is  cemented  into  a  hard  conglomerate,  drifts 
*  Bowie,  op.  cit. 


EXPLOITATION.  297 

are  run  into  the  bank ;  they  are  charged  with  a  number  of  25lb. 
kegs  of  powder,  tamped  up,  and  fired  by  electricity.  The  jets  of 
water  will  then  do  the  rest. 

The  gravel  washed  down  by  the  jets  of  water  is  led  first  into 
ditches  cut  in  the  "bed-rock,"  and  then  into  " sluices."  Sluices 
are  large  troughs  or  launders  lying  upon  the  ground,  and  paved 
with  loose  blocks  of  wood  or  with  stones,  in  order  to  form  a 

FIG.  341. 


surface  fit  for  catching  the  gold  and  the  amalgam.  Figs.  342,  343, 
and  344,*  show  a  section,  elevation  and  plan  of  a  sluice-box  with 
two  kinds  of  lining  ordinarily  adopted.  It  will  be  seen  that 
the  sluice  in  this  case  is  a  trough  5  feet  3  inches  wide,  made  of 
ij  inch  plank  at  the  sides  and  2-inch  plank  at  the  bottom,  upon 
which  are  placed  blocks  of  wood  20^  inches  square,  and  13  inches 
deep,  set  with  the  grain  on  end.  They  are  separated  at  the 
bottom  by  cross  strips  of  wood  i  J  inches  thick,  and  the  sides  are 
protected  by  blocks  3  inches  thick.  At  one  end  the  paving  is  of 
large  stones. 

The  sluice  is  generally  made  in  twelve-foot  llngths,  and  the 
inclination  is  commonly  defined  by  the  fall  given  to  such  a  length. 
*  Bowie,  op.  cit.,  p.  222. 


298 


ORE  AND  STONE-MINING. 


FIG.  342 


w 

4x6x4" 


FIG.  343. 


FIG.  344. 


IP  LH1 

LONGITUDINAL  SECTION  A  B, 


EXPLOITATION.  299 

Thus  it  is  said  that  the  grade  is  6  inches,  meaning  6  inches  to 
1 2  feet  or  J  inch  to  the  foot.  The  run  of  sluices  may  be  several 
hundred  or  several  thousand  feet  long. 

The  false-bottoms  for  sluices  are  called  "riffles."  The  wood 
preferred  for  the  block-riffles  is  that  of  the  "  digger  "  pine  (Pinus 
sabiniana).  Longitudinal  riffles  are  made  of  poles,  wooden  rails 
covered  with  strips  of  iron,  or  iron  rails,  In  New  Zealand*  the 
riffles  are  sometimes  made  of  transverse  bars  of  angle-iron,  riveted 
to  angle-iron  or  placed  in  a  wooden  frame,  which  enables  them  to 
be  reversed  when  worn.  The  sluice-boxes  are  lined  with  thin 
sheet  iron,  and  sacking  or  cocoa-nut  matting  is  placed  under  the 
riffles  to  assist  in  retaining  the  gold. 

In  order  to  catch  its  gold  more  effectually,  the  finer  material 
is  taken  out  and  treated  separately  in  broad  sluices  called  "  under- 
currents," at  the  side  of  the  main  one.  A  grating  of  bars  of 
iron,  i  inch  apart,  called  a  "grizzly,"  is  fixed  across  the  main 
sluice,  and  the  fine  gravel  and  sand  which  drop  through  are  led 
to  a  broad,  shallow,  sloping  box,  eight  or  ten  times  as  wide  as  the 
sluice  itself,  and  paved  like  it  with  stones,  wooden  blocks,  or 
longitudinal  riffles.  The  finer  portions  of  the  gravel,  after  passing 
over  the  "undercurrent"  and  depositing  much  of  their  gold,  are 
once  more  turned  into  the  main  sluice  lower  down. 

The  big  boulders  rushing  down  the  sluice  are  of  service  at  first 
by  breaking  up  gravel  which  is  much  cemented  together,  but  at 
the  same  time  they  naturally  wear  out  the  sides  and  the  pavement. 
It  is  therefore  advisable  to  get  rid  of  them,  as  soon  as  they  have 
done  all  the  useful  work  they  are  capable  of  performing.  This  is 
effected  by  arranging  a  "  grizzly "  or  grating  which  will  deliver 
the  boulders  into  a  ravine  or  gully,  and  so  dispose  of  them  without 
any  further  cost. 

Mercury  is  added  several  times  a  day  at  the  head  of  the 
sluice ;  and  the  upper  part,  say,  the  first  1000  feet,  is  cleaned  up 
every  two  or  three  weeks.  At  the  time  of  the  clean-up  the 
washing  down  of  the  gravel  bank  is  stopped,  or  the  current  is 
diverted  into  a  parallel  line  of  sluices.  A  small  quantity  of  water 
is  turned  into  the  sluice  which  is  to  be  cleaned  up,  the  blocks  are 
then  taken  out,  washed,  and  put  on  one  side.  All  the  amalgam 
is  picked  up  with  iron  scoops,  washed,  and  squeezed  through 
canvas  or  leather,  and  the  amalgam  is  retorted.  The  spongy 
gold  remaining  behind  in  the  retorts  is  then  finally  melted 
into  bars.  The  mercury  recovered  by  condensation  is  used  over 
again. 

When  the  bed-rock  is  below  the  drainage  level,  the  hydraulic 
elevator  *  may  be  employed.  A  jet  of  water  under  heavy  pressure 

*  Eickard,  "  The  Gold-fields  of  Otago  and  Alluvial  Mining  in  Otago," 
Trans.  Amer.  Inst.  M.  E.,  vol.  xxi.  1892,  p.  443  and  455  ;  Parliamentary 
Reports  on  the  Mining  Industry  of  New  Zealand,  Wellington,  1891,  p.  67, 
with  plates. 


300 


ORE  AND  STONE-MINING. 


is  brought  by  a  pipe  A  (Figs.  345  to  348)  to  the  nozzle  B,  and 
rushes  up  the  pipe  D,  producing  a  powerful  suction  in  the 
"  hopper "  C.  The  water  and  gravel  are  carried  up  against  the 
cast-iron  striking  plate  S,  and  then  run  down  the  sluice-boxes. 

FIG.  345. 


Fig.  349  explains  the  method  of  using  the  elevator  for  treating 
an  immense  accumulation  of  tailings  at  the  Blue  Spur,  Otago, 
N.Z.  On  the  left  hand  side  is  a  huge  nozzle  playing  upon  the 
face  of  the  tailings,  59  feet  high,  and  washing  clown  the  gravel 
and  sand  of  which  they  are  composed.  To  the  right  is  the  first 
elevator,  which  raises  the  stuff  15  J  feet  into  a  set  of  sluice-boxes, 
and  further  to  the  right  is  a  second  elevator  lifting  it  56  feet 
vertically  into  another  run  of  sluice-boxes. 


EXPLOITATION. 


301 


The  quantity  of  water  used  is  measured  by  a  unit  called  the 
"  miner's  inch,"*  which  unfortunately  is  not  invariably  the  same.. 
The  term  means  the  quantity  of  water  discharged  per  square 
inch  of  sectional  area  of  an  orifice  cut  through  a  vertical  board, 
forming  one  side  of  a  box.  The  discharge  will  necessarily  vary 
with  the  height  of  the  surface  of  the  water  above  the  orifice,  the 
thickness  of  the  board,  and  the  shape  and  nature  of  the  orifice  ; 
as  these  factors  of  the  problem  are  not  the  same  in  all  localities, 
it  is  impossible  to  give  one  definite  value  for  the  miner's  inch  of 
water.  The  orifice  is  usually  rectangular,  but  it  may  differ  in  height 
and  width.  However,  the  quantity  represented  by  the  miner's- 
inch  may  be  taken  as  varying  from  2000  to  2600  cubic  feet  per 

FIG.  349. 


THE   BLUE-  SPUN 

OtBtfO.    X   X. 


24  hours;  in  some  cases  the  outflow  is  reckoned  for  10  hours  only, 
and  is  spoken  of  as  the  "  ten  hours  miner's  inch." 

Under  these  circumstances  it  is  evident  that  great  care  must 
be  taken  to  ascertain  precisely  what  inch  is  meant,  before  making 
any  estimates  based  upon  this  uncertain  unit,  the  miner's  inch. 

The  "duty"  of  the  miner's  inch  is  "the  quantity  of  material 
washed  by  an  inch  of  water  in  24  hours."  As  might  be 
expected,  the  duty  varies  very  considerably,  indeed  from  i  to  4 
cubic  yards.  The  duty  necessarily  depends  upon  the  pressure  o: 
the  jet  of  water,  and  upon  other  causes,  such  as  "  character  of 
the  material  washed,  height  of  banks,  use  of  explosives,  size  and 
grade  of  sluices,  and  class  of  riffles.  The  sluice  affects  the  duty 
of  the  inch  in  so  far  as  its  capacity  regulates  the  quantity 
washed."  f 

Under   favourable  conditions  at    Cherokee    Flat,£ — viz.,    fine 

*  "  The  Auriferous  Gravels  of  California,"  Ninth  Annual  Report  of  the 
State  Mineralogist  for  the  year  ending  December  i,  1889  ;  Sacramento,  1890, 
p.  122  ;  and  Bowie,  op.  cit.  p.  124. 

f  Bowie,  op.  cit.  p.  268.  +  Bowie,  op.  cit.  pp.  268,  269. 


302  ORE  AND  STONE-MINING. 

material,  high  banks,  head  of  300  to  350  feet,  and  grade  ^, 
5*5  cubic  yards  are  said  to  be  the  duty  of  the  miner's  inch. 

At  Osceola,*  in  Nevada,  the  average  washing  in  1890  was  1-62 
cubic  yards  to  the  inch  of  water  and  it  was  expected  that  the 
duty  would  be  raised  eventually  to  2  cubic  yards. 

It  is  hardly  necessary  to  say  that  the  yield  of  the  gravel  varies 
between  very  wide  limits,  and  it  is  consequently  impossible  to  lay 
down  any  average  for  the  hydraulic  mines  of  California  or  any 
other  country.  But  the  accompanying  table  gives  the  results  of 
actual  work,  and  will  at  all  events  show  that  poor  gravel,  con- 
taining gold  worth  only  10  or  15  cents,  say,  $d.  to  j^d.  per  cubic 
yard,  can  sometimes  be  made  to  pay  good  profits. 

With  the  exception  of  Osceola,  the  works  were  all  in  California  • 
the  figures  are  borrowed  from  Mr.  Bowie,  and  many  other  ex- 
amples of  the  yield  of  auriferous  gravel  will  be  found  in  his  work 
and  in  Mr.  Hammond's  report. 

A  cubic  yard  of  gravel  is  estimated  by  Mr.  Hammond  to  weigh 
from  i  J  to  if  tons. 

One  of  the  great  difficulties  with  which  the  hydraulic  miner  has 
to  contend  is  getting  rid  of  the  enormous  quantities  of  refuse 
produced  by  his  washings.  Some  idea  of  these  quantities  will  be 
gathered  from  the  statement  that  one  working  alone,  the  Gold 
Bun  Ditch  and  Mining  Company,  was  for  a  period  of  eight  years 
discharging  4000  to  5000  cubic  yards  of  sand,  gravel  and  boulders 
daily  into  a  tributary  of  the  Sacramento.  As  a  natural  con- 
sequence banks  were  formed  in  the  river,  obstructing  the 
navigable  channels,  rendering  overflows  more  frequent  and 
destructive,  and  causing  valuable  land  to  be  destroyed  by  de- 
posits of  sand.  Litigation  ensued,  and  some  years  ago  the 
Superior  Court  of  Sacramento  decided  that  the  hydraulic  mining 
companies  must  build  dams  to  impound  the  coarse  and"  heavy 
debris,  or  take  other  means  to  prevent  their  being  washed  down 
the  rivers. 

The  consequence  of  this  decision  was  a  great  diminution  of  the 
amount  of  hydraulic  mining  carried  on  in  the  State ;  but  quite 
lately  an  Act  of  Congress  has  been  passed  which  will  allow  work 
to  be  resumed  at  many  of  the  mines. 

(2)  EXCAVATION  OF  MINERALS  UNDER  WATER. 
— In  Chapter  IY.  mention  was  made  of  dredges  of  various  types, 
which  are  employed  for  the  purpose  of  extracting  gold-bearing 
sand  and  gravel  from  the  beds  of  rivers.  Gold  is  not  the  only 
mineral  worked  in  this  fashion ;  in  South  Carolina  phosphate  of 
lime  is  dredged  up  from  river-bottoms,  and  in  Prince  Edward 
Island  a  shell-marl  obtained  in  a  similar  manner  is  sold  as  a 
fertiliser.  Lastly,  on  the  coast  of  Germany,  between  Dantzig  and 
Memel,  two  forms  of  subaqueous  work  are  applied  to  the  getting 

*  Eng.  Min.  Jour.,  vol.  li.,  1891,  p.  630. 


EXPLOITATION. 


3°3 


oto.8 

CO 

^ 

or 

ON 

sJ'I'H        |         | 

|       £ 

| 

* 

5s 

"o 

00 

c? 

S"      1       o* 

<2  2,^ 

1 

i 

4 

4 

£ 

4 

£ 

vo           c> 

#*            & 

SSLS-p 

CO 

VO 

to     vo 

CO 

CO 

o 

o 

1 

g 

vg 

VO            N            H-C 

5||1 

4  & 

& 

i 

i 

i 

A 

& 

& 

1  A  i 

•J^BAV  J° 

^ 

CO 

vo 

00 

N 

oo 

r^. 

VO      N      ON 

qoui  jad  paAOra 

1 

CO 

\ 

p 

Tf 

op 

p 

OO     VO     OO 

spaB.C  oiqno 

" 

** 

1-1 

*-* 

•-' 

"* 

"* 

CO      w        M 

f- 

O 

O          N 

0 

£ 

vo 

Tj- 

0 

8 

8      CO"      ^ 

c3   >  ^ 

M 

*H            ON 

Q 

vo 

ON 

Q 

ON     •—  •      co 

r*  ^  > 

^ 

od      j* 

S 

V0~ 

10 

OO 

c£ 

0% 

CO    CO~      lO 

••^  ^-t  £ 

T^- 

hH                 C^ 

vo^ 

vo 

M 

N 

vo 

CXD 

o\ 

M            I-H            HH 

5  ° 

cT 

10 

CO 

N" 

"• 

N~ 

?i 

-2  i 

i 

1    1 

i 

O 
O 

G 

1 

3 

! 

1 

1  'a 

O 

10 

"3  ^ 

•M 
N 

oo  ^0 

4n 

IM 

d 

vO 

•<*• 

O 

s-a 
SJ 

•H 

0? 

O 
M 

i—  ( 

2| 

0    fc 

Tf 

O 

1 

O 

i 

1 

5  1  1 

^ 

HH        > 

o 

T^- 

^--^ 

-^ 

M 

N 

w 

0^ 

vo  vo 

in 
^    t2* 

«4H 

vo 

M 

VO 

N 

2 

M                VO 

25 

1     ££ 

1 

1-1    •U 

S 

1 

o 

O 

o 

5    |    5 

002 

• 

d  fl 

.S 

s 

r 

~ 

=         r 

•  r-l 

•  r-l 

'.-w' 

-JO* 

—hi 

HM                  H51 

CO  Tj- 

Tj- 

CO 

•* 

vo 

vd 

VO               CO 

^•—  s 

—J— 

d 
O 

* 

—  *— 

—J— 

| 

w 

-  O 

£H 

1 

^ 

-0* 

o>    - 

^O 

c3 

c/2  d 

jo  O 

d 

rS    O 

cS 

*" 

* 

1 

1 
3d 

f  Temperanc 
(  Yuba  Co 

Nevada  Co. 

f  Patricksvil 
{  Stanislaus 

Forest  Hill,  P 

go 

f  Patricksvil 
(  Stanislaus 

Stanislaus  C 

f  Patricksvil 
{  Stanislaus 

cu 

<J~) 

1 

CXD 

1 

oo 

**»  $ 

VO      ^ 

8 

• 

—  I  — 

a 

o 

. 

. 

3 

9 

0 

S 

trt 

a 

frl 

"3 

£D 

F-H 

o 

* 

1 

Blue  Grav 

Blue  Tent 
Chesnau 

DardanelL 

i 

1 

i 

Johnson 

La  Grange 

1 

o 

s 

I 

ft 

11 

O     02 

304  ORE  AND  STONE-MINING. 

of  amber.*  Some  is  dredged  up  by  bucket-dredges,  and  some  is 
obtained  by  divers.  The  divers  go  out  in  boats  about  three- 
quarters  of  a  mile  off  the  Briister  Ort  lighthouse,  and  after 
anchoring  they  descend  to  work  the  amber  bed,  being  equipped 
with  regular  diving  dresses,  and  supplied  with  air  by  pumps 
worked  by  their  comrades.  Carrying  a  crowbar  and  a  pronged 
iron,  the  diver  searches  for  masses  or  lumps  of  amber  and  detaches 
them  from  the  parent  bed,  or  finds  them  already  loosened  and 
dislodged  by  storms. 

(3)  EXTRACTION  OF  MINERALS  BY  WELLS  AND 
BOREHOLES. — Liquid,  gaseous  and  soluble  minerals  are 
sometimes  obtained  by  one  of  these  two  methods.  The  principal 
are  :  carbonic  acid,  natural  inflammable  gas,  petroleum,  and  salt. 

Carbonic  Acid. — Underground  supplies  are  tapped  by  bore- 
holes, and  the  getting  consists  simply  in  piping  off  the  gas  from 
the  top. 

Natural  Gas. — Precisely  the  same  remark  applies  in  the  case  of 
the  natural  gas  used  for  fuel  in  Pennsylvania,  the  occurrence  of 
which  has  already  been  described. 

Petroleum. — This  mineral  may  be  got  either  by  wells  or  bore- 
holes. In  the  United  States,  in  Galicia,  and  in  the  great  oil- 
district  on  the  Caspian  Sea,  boreholes  are  sunk  by  one  of  the 
processes  described  in  Chapter  III.,  and  it  is  found  that  the  oil 
will  either  rise  to  the  surface  or  part  way  to  the  surface.  In  this 
latter  case  it  has  to  be  drawn  up  by  pumps.  In  order  to  increase 
the  flow  of  oil  from  the  surrounding  rocks  into  the  bore-hole,  it 
is  usual  to  break  up  and  crack  the  oil-bearing  stratum  by  a 
torpedo.  This  is  a  powerful  charge  of  some  explosive  con- 
tained in  a  tin  cylinder,  which  is  lowered  into  the  hole  to  the 
required  depth  and  then  exploded.  Nitroglycerine,  dynamite  or 
gunpowder  are  employed,  but  of  course  the  last  is  only  used  when 
its  more  powerful  rivals  cannot  be  obtained.  As  much  as  a 
hundred  quarts  of  nitroglycerine  may  be  used  for  one  blast,  in 
which  case  the  explosive  is  let  down  in  separate  cylinders,  each 
containing  twenty  quarts.  The  explosion  of  the  top  cylinder  fires 
the  charges  in  the  others. 

In  Burmah  the  petroleum  is  got  by  wells,  and  this  was  the 
manner  by  which  the  great  Russian  deposits  were  worked  until 
comparatively  lately.  The  oil  gradually  oozes  out  of  the  sur- 
rounding strata  and  accumulates  in  the  bottom  of  the  well,  whence 
it  is  drawn  up  by  earthenware  pots. 

Salt. — The  great  bed  of  salt  at  and  near  Middlesbrough  is 
worked  by  making  a  borehole  and  putting  in  two  tubes  and  a 
pump,  so  arranged  that  water  from  a  superincumbent  bed  of 
sandstone  travels  down,  dissolves  the  salt,  and  is  then  drawn  up. 
The  process  pursued  will  be  apparent  from  an  inspection  of  the 

*  "  The  Amber  Fisheries  of  the  Baltic,"  Evening  Standard,  Sept  12,  1888. 


EXPLOITATION. 


305 


figure.  A  drive-pipe  aa  (Fig.  350)  is  first  rammed  down  through 
the  alluvial  soil,  in  the  manner  described  by  Fig.  142,  and  a  borehole, 
8  inches  in  diameter,  is  put  down  through  the  sandstone,  gypseous 
marl,  and  the  whole  thickness  of  the  rock-salt,  until  it  has  reached 

FIG.  350. 


.  »  Sandstone 


'ypsum 
—  and 
'  _   _ —    Anhydrite 


Rocksalt 
>>»»»».  Anhydrite 


—       Marl 


the  underlying  anhydrite.  It  now  has  to  be  lined  with  a  steel 
tube  bb  (Fig.  350,  in  which  the  size  of  the  tubes  is  greatly 
exaggerated),  6f  inches  in  diameter  internally;  for  the  first  150 
feet  from  the  bottom  the  steel  is  J  inch  thick,  then  T5^  inch  for 
300  feet,  and  the  remainder  is  |  inch  thick.  With  the  sleeve 

u 


306  OKE  AND  STONE-MINING. 

couplings  over  them,  the  tubes  just  pass  down  the  drive-pipe.  In 
the  rock-salt  and  in  the  600  feet  of  water-bearing  sandstone, 
the  lining  pipe  is  perforated  with  holes  i  inch  in  diameter,  and 
1 2  inches  apart  vertically. 

Lastly,  a  steel  suction  pipe  (Fig  350,  c),  3  inches  in  diameter 
internally,  and  J  inch  thick,  made  in  2o-feet  lengths,  united  by 
sleeve  couplings,  is  lowered  into  the  borehole;  about  240  feet 
from  the  surface  is  fixed  a  brass  working  barrel  (Fig.  350,  d),  6  feet 
long,  4!  inches  in  diameter  and  ^  inch  thick,  and  above  it  steel 
tubes,  4 1  inches  in  diameter,  which  reach  to  the  surface.  The 
working  barrel  has  a  ball  valve  at  the  bottom.  When  the  pump 
bucket,  also  fitted  with  a  ball  valve,  has  been  let  down  by  a  series 
of  rods,  and  the  last  one  has  been  connected  to  the  end  of  the 
walking  beam,  the  extraction  of  brine  can  commence.  It  is 
evident  from  the  figure  that  when  a  pump  is  set  in  motion  at  d, 
water  will  ascend  the  suction  pipe,  and  its  place  will  be  taken  by 
water  from  the  sandstone.  This  descends  the  outer  tube  to  the 
rock-salt,  brings  it  into  solution,  and  is  pumped  up  as  brine. 
As  the  pumping  proceeds,  the  rock-salt  is  gradually  eaten  away 
all  round  the  borehole ;  in  time  the  marl  roof  must  fall  in,  and 
eventually  the  pipes  will  get  more  or  less  choked,  and  the  brine 
will  be  too  weak  to  be  worth  pumping. 

The  rate  of  pumping  is  regulated  so  that  the  brine  is  delivered 

with  25  per  cent,  of  salt.     As  it  comes 

FIG.  351.  up  it  is  full  of  gas,  which  is  mainly 

nitrogen  with  a   small  proportion  of 

hydrocarbons. 

The  boreholes  are  arranged  in  fours 
at   the   corners  of  a   square,   with    a 
-400ft—         —>•     diagonal  of  200  feet  (Fig.  351). 

The  brine  is  delivered  into  a  large 
storage  and  settling-pond,  whence  it 
flows  into  sheet-iron  evaporating 
pans. 

0  If  there  is  no  natural  supply  avail- 

able, as  is  the  case  in  the  Middles- 
brough district,  fresh  water  from  the  surface  is  run  down  the 
outer  pipe,  and  the  dissolving  proceeds  as  before. 

Natural  sheets  of  saline  water  or  brine  can  be  tapped  by  wells 
or  boreholes  in  some  districts ;  indeed  salt  was  worked  in  this 
way  in  Cheshire  long  before  the  discovery  of  the  rock-salt.  Some 
of  the  Cheshire  salt  is  derived  from  brine  pumped  up  from 
inundated  mines  worked  originally  for  rock-salt,  which  are  now 
full  of  water  and  cannot  be  entered. 

This  therefore  is  practically  a  combination  of  underground  work 
with  extraction  by  solution,  and  the  process  which  in  these  cases 
has  been  finally  adopted,  through  force  of  circumstanceSj  is  some- 
times found  advisable  from  the  commencement. 


EXPLOITATION.  307 

Gallon*  describes  and  figures  the  method  of  working  the  salt 
•marls  of  the  Salzkammergut  by  huge  elliptical  chambers.  A 
network  of  drivages  is  first  of  all  made  at  the  floor  of  the  proposed 
chamber,  and  then  fresh  water  is  brought  in,  until  it  fills  the 
excavations  and  gradually  eats  away  the  pillars  and  roof.  The 
brine  is  pumped  up  and  the  clayey  matter  falls  on  the  floor  of  the 
chamber  and  is  left  there. 

At  Bex  in  Switzerland  the  process  is  similar,  only  it  has 
to  be  adapted  to  the  nature  of  the  deposit  worked.  The  salt 
occurs  in  the  form  of  large  lenticular  masses  of  saliferous 
anhydrite  surrounded  by  anhydrite  free  from  salt.  The  lenses 
are  from  10  to  50  metres  wide,  and  are  known  to  extend  to  a 
•depth  of  300  or  400  metres,  dipping  almost  vertically. 

A  main  shaft  is  sunk  and  the  saliferous  rock  is  reached  by  cross- 
•cuts  and  dissolved  away  in  slices  100  metres  thick  at  a  time. 

An  intermediate  shaft,  or  winze,  is  sunk  from  the  crosscut, 
.and  when  it  has  reached  a  depth  of  100  metres  a  second  crosscut 
is  put  out,  from  which  two  long  drivages,  2  metres  high  and 
i '5oni.  wicfe,  are  made  in  the  direction  of  the  major  axis  of  the 
deposit.  By  a  series  of  drivages  at  right  angles  to  each  other, 
the  lowest  part  of  the  slice  is  cut  up  into  a  set  of  square  pillars 
about  5  or  6  metres  on  the  side.  Water  is  let  into  the  winze,  and 
is  allowed  to  rise  to  the  level  of  the  upper  crosscut.  It  dissolves 
the  salt  from  the  rock,  is  pumped  up,  piped  out  to  the  surface 
through  a  long  adit,  and  evaporated.  As  the  strongest  brine 
sinks  to  the  bottom,  the  pumps  are  made  to  take  their  supply  from 
the  lowest  part  of  the  workings.  The  saliferous  anhydrite  contains 
from  25  to  30  per  cent,  of  salt,  and  when  this  has  been  dis- 
solved out,  the  rock  does  not  fall  to  pieces  as  might  have  been 
expected.  Gypsum  is  soluble  in  water  containing  10  to  14  per 
cent,  of  salt,  so  the  first  action  of  the  water  is  to  dissolve  some 
of  the  anhydrite ;  but  when  the  brine  becomes  more  concentrated, 
gypsum  is  deposited  in  the  form  of  small  crystals,  which  bind 
the  anhydrite  into  a  firm  mass.  Consequently  the  leached  rock 
stands  perfectly  well  by  itself,  and  there  is  no  fear  of  the  sides 
falling  in. 

One  of  these  large  workings,  when  once  properly  laid  out,  will 
go  on  furnishing  brine  for  thirty  or  forty  years.  The  rate  of 
pumping  is  regulated  so  as  to  supply  brine  with  25  to  26  per  cent, 
•of  salt. 

A  last  instance  of  a  combination  of  underground  workings  and 
extraction  by  watery  solution  may  be  taken  from  Parys  Mountain 
in  the  island  of  Anglesey.  During  the  active  working  of  the 
Parys  mine  many  years  ago,  poor  copper  ore  which  had  been 
broken,  but  which  would  not  pay  for  the  expense  of  winding  and 
dressing,  was  left  underground.  Under  the  action  of  air  and 

*  Lectures  on  Mining,  vol.  ii.  p.  23  ;  Atlas,  plate  xliii.  Figs.  251,  252. 


308  ORE  AND  STONE-MINING. 

moisture,  the  chalcopyrite  in  the  refuse  and  in  the  pillars  is 
gradually  decomposed,  producing  a  certain  quantity  of  soluble 
sulphate  of  copper.  Rain  finding  its  way  down  the  mine  dissolves 
the  sulphate,  and  the  pumps  draw  up  a  strongly  coloured  water, 
which  in  contact  with  scrap  iron  yields  merchantable  copper 
precipitate.  The  mine  is  now  worked  solely  in  this  way. 

In  a  like  manner  a  little  copper  has  been  got  from  the  water 
flowing  out  of  the  County  adit  in  Cornwall. 

(4)  UNDERGROUND  WORKINGS.— The  methods  em- 
ployed for  excavating  minerals  underground  are  almost  as  various 
as  the  different  forms  in  which  the  minerals  themselves  occur. 

The  deposit  must  first  be  reached  by  a  shaft,  or,  where 
the  contour  of  the  country  permits  it,  by  an  adit.  The  choice 
between  these  two  methods  of  attack  must  be  entirely  governed 
by  the  circumstances  of  the  case.  In  a  comparatively  level  country, 
it  would  be  impossible  to  bring  in  an  adit  capable  of  rendering 
any  real  service  without  going  to  a  distance  which  would  make  the 
cost  of  driving  prohibitory;  but  among  the  mountains  an  adit 
may  be  the  quickest  and  cheapest  means  of  entering  productive 
ground.  It  has  the  advantage  of  enabling  all  pumping  to  be 
dispensed  with  for  a  time,  of  reducing  subsequent  water-charges, 
of  affording  an  opportunity  of  easily  utilising  water  supplies  in 
the  neighbourhood,  and  often  of  bringing  out  the  mineral  to  a 
more  suitable  locality  for  treatment  than  could  be  obtained  by 
raising  it  perpendicularly  to  the  surface.  Instances  often  occur 
in  which  the  adit  can  be  driven  along  the  course  of  the  deposit 
itself,  and  so  furnish  valuable  data  concerning  it.  A  shaft 
sunk  upon  the  dip  of  a  deposit  has  this  same  advantage  ;  but 
here  it  is  necessary  to  remark  that  the  term  "  shaft "  does  not 
always  convey  the  same  meaning.  The  ore-miner  uses  the  word 
to  denote  not  only  a  vertical  pit,  but  also  one  sunk  upon  a  vein, 
even  if  the  inclination  is  but  slight.  There  are  portions  of  shafts 
in  Cornwall  which  do  not  dip  more  than  1 5  degrees  from  the 
horizontal.  Shafts  with  an  inclination  of  60°  or  70°  from  the 
horizontal  are  common  in  vein-mining,  and  no  ore-miner  would 
think  of  calling  them  by  any  other  name.  On  the  other  hand, 
the  coal-miner  seems  to  confine  the  word  shaft  to  vertical  pits. 
If  a  pit  is  sunk  vertically  till  it  meets  a  seam  of  coal,  and  is  then 
continued  along  the  dip  of  the  bed,  the  latter  sloping  part  of  the 
excavation,  even  if  it  has  a  dip  of  50°  or  60°.  is  called  an  "  in- 
cline," and  not  a  shaft.  The  term  "  slope  "  is  used  in  places  to 
denote  an  inclined  pit  along  the  dip  of  the  strata. 

We  will  suppose  that  the  deposit  has  been  struck  by  a  shaft, 
incline,  or  level.  The  problem  is  how  to  remove  it  to  the  best 
advantage.  As  the  conditions  are  so  various,  it  is  advisable  to 
classify  the  methods  according  to  the  nature  of  the  deposit,  and 
treat  separately  the  modes  of  working — (i)  beds  ;  (2)  veins;  and 
(3)  masses. 


EXPLOITATION. 


309 


FIGS.  352  &  353. 


BEDS.  -  -  Two  great  divisions  stand  out  prominently  : 
{A)  Methods  in  which  the  bed  is  cut  out  into  pillars;  and 
{B)  methods  in  which  the  bed  is  removed  at  once  without  this 
preliminary  treatment.  In  the  former  the  pillars  may  either  be 
left  as  permanent  supports,  or  they  may  be  removed  in  a  second 
sta.ge  of  the  process  of  exploitation.  We  have  thus  three  prin- 
cipal processes  of  working  to  consider7  as  shown  in  the  following 
table  : 

[Ai.  Pillars  left  as  permanent  supports. 
(A.  Pillar  workings,   -j 

Beds  J  (A2.  Pillars  worked  away. 

(B.  Longwall  workings. 

Ai.  Pillars  Left  as  Permanent  Supports. — This  system 
is  adopted  with  minerals  of  no  great  intrinsic  value,  as  it  is  often 
better  to  lose  much  of  the  mineral  in  the  form  of  pillars,  than  to 
go  to  the  expense  of  putting  in  artificial  supports  during  the 
period  of  exploitation. 

The  method  can  be  best  understood  by  giving  a  few  charac- 
teristic examples  taken  from  minerals 
of  various  kinds — viz.,   gypsum,  iron 
pyrites,  limestone,  salt,  and  slate. 

Gypsum. — Figs.  352  and  353  repre- 
sent in  section  and  in  plan  the  cham- 
bers and  pillars  of  the  underground 
gypsum  quarries  at  Paris,  which  supply 
the  stone  from  which  the  well-known 
plaster  is  made.*  The  principal  bed 
is  from  50  to  60  feet  in  thickness. 
Pillars  are  left  10  feet  square  at  the  m  pn  pa  k 

base,  and  the  stalls  between  them  are 
1 6  feet  wide.  The  workings  are  slightly  H     111     11 

arched,  and  are  not  carried  up  to  the 

true  roof,  for  the  purpose  of  better  maintaining  the  security  of  the 
chambers,  because  heavy  damages  would  have  to  be  paid  if  they 
"  caved  in  "  arid  rendered  the  surface  useless.  A  similar  layer  of 
gypsum  left  for  the  floor  prevents  "creep" — that  is  to  say,  arising 
of  the  floor  owing  to  the  thrust  of  the  pillars,  and  enables  the 
underground  roads  to  be  kept  in  order  with  little  expense. 

In  Nottinghamshire  the  poor  parts  of  the  bed  of  gypsum  are 
left  as  pillars,  and  they  are  sufliciently  frequent  to  prevent  any 
waste  of  good  rock  for  supports. 

Iron  Pyrites. — At  Cae  Coch  Mine,  near  Llanrwst  in  North 
Wales,  there  is  a  bed  of  iron  pyrites,  about  8  feet  thick,  which 
is  worked  by  leaving  pillars  from  2  to  3  yards  in  diameter,  at 
intervals  of  8  or  10  yards.  The  pillars  are  somewhat  irregular, 
because  where  the  roof  is  firm  and  strong  more  space  can  be 

*  Gallon,  Lectures  on  Mining,  vol.  ii.  plate  xli. 


3io 


ORE  AND  STONE-MINING. 


left  without  support.  If  the  roof  appears  at  all  weak,  the- 
pillars  are  made  closer  together.  The  excavations  are  slightly 
arched  at  the  top,  so  as  to  obtain  a  little  more  strength. 

Limestone. — A  considerable  quantity  of  limestone  is  wrought 
in  this  country  by  underground  mining,  especially  in  Wiltshire, 
Worcestershire,  South  Staffordshire,  and  Scotland. 

The  beds  of  freestone  which  are  worked  near  Bath  occur  in  the 
Great  Oolite,  and  vary  from  8  or  9  to  1 8  or  24  feet  in  thickness  -r 
the  dip  is  slight,  being  only  i  in  33. 

FIG.  355- 

Section 


FIG.  354. 
<-2 
\side hole     \    Wjisidehole 

* 
Main  heading  j£» 


,-J 


I  side  hole 


The  bed  of  stone,  which  it  is  proposed  to  work,  is  reached  by 
an  inclined  plane,  and  a  main  heading  is  driven  out  15  to  i6< 
feet  wide,  with  "  side  holes "  at  right  angles,  as  wide  as  the 
roof  or  ceiling  will  admit  with  safety,  say  20  feet  to  24  feet, 
leaving  pillars  10  feet  square  and  upwards  (Fig.  354).  If  any 
rock  is  unsound,  it  is  left  as  a  pillar,  and  this  may  cause  som& 
irregularity  in  the  plan  of  the  mine. 

The  first  process  in  removing  the  stone  consists  in  excavating 
the  "  jad,"  a  horizontal  groove  at  the  top  of  the  bed,  which  is 

cut  in  for  a  depth  of  5  feet 

FIG.  356.  and   a  width  of  20   to  25, 

Ap/«v  feet  (Figs.  355  and  356). 

After  the  jad  has  been, 
excavated  with  the  pick 
(Fig.  355),  a  vertical  cut  is 
made  with  a  saw  along  the 
line  BA  (Fig.  356),  and 
another  along  the  line  DC, 

and  a  piece  ABDC,  called  the  "  wrist,"  is  wedged  up  from  the 
bottom  or  off  from  the  side  ;  it  breaks  along  the  line  AC.  When 
the  "  wrist "  has  been  removed,  the  blocks  are  simply  cut  out 
with  saws.  These  saws  are  6  or  8  feet  long  by  10  inches  to  12 
inches  wide.  The  first  saw  used  in  the  jad  has  to  be  narrower, 
and  is  called  the  "  razor  saw." 

The  heaviest  saw  weighs  56  Ibs.,  and  the  handle  ca,n  be  fixed 


-20to25ft.- 


EXPLOITATION.  311 

as  shown  by  the  dotted  lines  (Fig.  156),  or  entirely  below  the  eye 
for  working  immediately  below  the  roof. 

When  set  free  by  sawing  on  all  four  sides,  the  block  is  easily 
detached  by  wedges  driven  in  along  a  plane  of  bedding.  The 
blocks  are  lifted  off  by  cranes,  and  either  loaded  at  once  on  to 
trucks  or  stacked  inside  the  quarry,  after  having  been  roughly 
dressed  with  an  axe  or  with  a  saw. 

A  workman  can  saw  1 5  square  feet  of  the  softest  beds  in  an 
hour. 

In  the  neighbourhood  of  Dudley  there  are  two  beds  of  Upper 
Silurian  limestone  worked  by  true  mining.  The  top  bed  is  from 
1 6  to  1 8  feet  thick,  and  it  is  got  by  a  system  of  pillars  and 
chambers.  The  pillars  are  8  yards  square,  and  the  stalls  between 
them  13  to  17  yards.  Near  the  outcrop  both  the  pillars  and  the 
stalls  are  rather  smaller  than  this.  The  top  2  feet  of  stone  are 
left  to  support  the  roof. 

Salt. — The  salt  mines  of  Cheshire  *  are  an  excellent  example  of 
pillar  and  chamber  workings.  The  bed  is  84  feet  thick,  but  only 

FIG.  357.  FIG.  358. 


the  bottom  part,  15  to  18  feet  thick,  is  mined.  Pillars  10  yards 
square  are  left  promiscuously,  about  25  yards  apart,  or  closer  if 
thought  desirable  in  any  special  places.  Fig.  357  represents  part  of 
Marston  Hall  Mine  near  Northwich.  The  bed  is  almost  horizontal, 
and  is  reached  by  two  perpendicular  shafts  ;  wide  stalls  are  then 
driven  out  on  all  sides.  The  workings  are  advanced  by  making 
an  excavation  in  the  upper  part  called  the  "  roofing  "  (a,  Fig.  358) ; 
and  the  lower  two-thirds  of  the  thickness  worked  are  got  by 
blasting  slanting  holes.  This  part  is  called  the  "  benching."  The 
roofing  is  made  by  holing  or  under-cutting  by  hand,  or  better  by 
a  Walker  circular  saw  driven  by  compressed  air  (Fig.  216),  and 
bringing  away  the  salt  by  horizontal  holes  bored  with  a  jumper 
and  charged  with  gunpowder. 

The  old  method  of  working  salt  in  Koumania  f  was  by  bell- 
shaped  pits,  which  were  widened  out  gradually  till  their  diameter 

*  Dickinson,  "Keports  on  the  Salt  Districts,"  Reports  of  tlie  Inspectors  of 
Mines  for  the  Year  1881,  p.  66. 

t  Notice  sur  la  JRoumanie.  Exposition  Vniversalle  de  Paris  en  1889,  pp.  1 16 
to  119. 


312  ORE  AND  STONE-MINING. 

reached  160  to  200  feet  (50  to  60  m.),  after  which  the  sides  were 
carried  down  vertically. 

Nowadays  long  chambers  are  excavated  with  intervening  pillars, 
A  chamber  is  begun  by  driving  a  level  10  to  50  feet  wide 
(3  to  1 6  m.),  and  this  is  deepened  and  widened  at  the  same  time, 
so  that  the  sides  make  an  angle  of  30°  to  45°,  until  the  full  width 
of  1 64 feet  (50  m.),  is  attained;  the  excavation  is  then  continued 
with  vertical  sides.  The  section  therefore  resembles  that  of  an 
ordinary  house.  A  gangway  is  carried  round  the  roof  for  the 
purpose  of  inspecting  it  regularly. 

At  Turgu-Ocna  Mine  there  are  four  of  these  chambers  which 
will  eventually  vary  from  100  to  160  feet  in  width  (30  to  49  m.) 
and  450  to  560  feet  (138  to  170  in.)  in  length,  and  afford  a  total 
working  area  of  22,000  square  yards  (18,550  square  metres). 

As  regular  blocks  of  almost  uniform  weight  are  preferred  for 
exportation,  great  pains  are  taken  to  get  out  the  rock-salt  in 
the  form  which  meets  with  the  readiest  sale,  and  to  reduce  the 
quantity  of  "  smalls  "  to  a  minimum.  The  blocks  are  cut  by  hand 
or  by  machine.  Three  cutting  machines  are  used  :  one  makes 
horizontal  cuts  in  the  direction  of  the  long  axis  of  the  chamber, 
the  second  vertical  cuts,  and  the  third  transverse  cuts,  so  as  to 
divide  the  rock-salt  into  regular  cubes,  about  one  foot  on  the  side, 
weighing  132  Ibs.  each  (60  kil.). 

Slate. — In  the  Festiniog  district  in  North  Wales  the  principal 
bed  is  120  feet  (36 \  metres)  thick  in  places,  and  there  are  others 
from  30  to  70  feet  thick;  these  beds  are  spoken  of  as  "veins," 
though  they  are  true  sedimentary  deposits.  The  dip  of  the  beds 
is  from  20°  to  30°  or  35°,  whilst  the  dip  of  the  planes  of  cleavage 
is  about  45°;  the  strike  of  the  planes  of  cleavage  is  very  nearly 
the  same  as  the  strike  of  the  planes  of  bedding. 

The  method  of  working  consists  in  making  a  series  of-  parallel 
chambers  (openings)  separated  by  pillars  (walls).  These  do  not 
follow  the  dip,  but  run  somewhat  askew,  because  it  is  found 
that  the  slate  rends  well  at  right  angles  to  the  cleavage  planes 
in  a  direction  which  does  not  coincide  with  the  dip  exactly.  The 
width  of  the  chambers  along  the  line  of  strike  varies  accord- 
ing to  the  firmness  of  the  bed  selected  as  roof  of  the  chamber, 
and  is  commonly  from  35  to  50  feet.  The  width  of  the  inter- 
vening pillars  is  usually  somewhat  less. 

The  workings  are  divided  into  a  succession  of  floors  about  50  feet 
one  below  the  other  vertically.  The  first  operation  consists  in  reach- 
ing the  bed  by  means  of  an  adit  or  an  incline  sunk  along  the  dip  of 
the  bed  and  then  levels  are  driven  out  along  the  strike,  A  B  C  D  (Fig. 
359,  plan  ;  Fig.  360,  cross  section),  under  some  bed  which  offers  the 
necessary  guarantee  of  solidity,  very  often  an  altered  volcanic  ash. 
When  a  new  level,  such  as  D  (Fig.  360),  has  been  driven  a  certain 
distance  it  is  connected  with  the  level  above  by  an  inclined  drift 
called  a  "  roof."  The  "  roof,"  or  "  rise  "  as  it  would  be  called  by 


EXPLOITATION.  313 

an  ore-miner,  is  a  passage  about  4  feet  high,  and  4  feet  wide, 
generally  excavated  from  below  upwards,  on  account  of  its  being 
more  economical  to  let  the  broken  rockfall  into  the  level  underneath 
than  to  draw  it  up  by  hand,  which  becomes  necessary  if  the  passage 
is  made  by  "sinking" — i.e.,  excavating  from  above  downwards. 
The  "roof"  is  usually  carried  up  on  one  side  of  the  proposed  new 
chamber.  The  third  step  in  the  process  is  the  "  widening,"  or 
excavation  of  the  rock  011  one  side  of  the  "  roof,"  until  the  slate  is 
uncovered  for  a  width  of  40  or  50  feet.  The  result  of  this  work  is 
the  formation  of  an  inclined  open  space  40  feet  long,  for  instance, 
along  the  strike,  and  stretching  up  from  one  level  to  the  next  one 
50  feet  above  it  vertically.  While  this  work  is  going  on,  the 
level  is  being  prolonged  ;  a  distance  of  30,  40  or  50  feet  is 
left  for  the  pillar,  and  eventually  a  new  "  roof  "  is  put  up  for  a 
second  chamber. 

In  most  cases  the  excavation  of  the 


FIG.  359. 


FIG.  360. 


roof"  and  the  process 
FIG.  361. 


of  widening  go  on  at  the  same  time,  because  it  is  found  that  the 
atmosphere  of  a  small  passage  like  a  "  roof "  naturally  becomes 
bad  during  work,  unless  it  is  provided  with  some  special  venti- 
lating appliance,  whereas  if  the  amount  of  space  is  increased,  the 
impurities  introduced  into  the  atmosphere  are  spread  over  a 
greater  volume  of  air,  and  the  evil  is  lessened. 

This  preliminary  work  of  driving  levels,  "  roofing  up,"  and 
"  widening,"  is  all  done  by  a  special  set  of  men,  known  as 
"  miners,"  to  distinguish  them  from  the  slate-getters,  who  are 
called  "  rockmen,"  for  slate  is  par  excellence  "  the  rock  "  in  the 
district. 

The  productive  period  of  the  life  of  a  chamber  now  begins. 
The  first  duty  of  the  rockmen  is  to  examine  very  carefully  the 
roof  of  the  chamber,  which  ought  to  have  been  left  perfectly 
secure  by  the  miners ;  but  as  the  rockmen  have  to  work  under 
it  possibly  for  ten  years  or  more,  they  naturally  are  anxious  to 
feel  that  every  chance  of  a  fall  has  been  prevented  as  far  as 
possible.  In  the  early  part  of  the  working  of  a  chamber,  when 
the  roof  is  within  reach,  the  examination  can  be  made  with  ease ; 


314  ORE  AND  STONE-MINING. 

later  on  when  the  slate  has  been  excavated,  or  partly  excavated, 
long  ladders  are  required,  and  the  task  becomes  much  more 
difficult. 

Having  satisfied  themselves  and  the  agents  that  all  is  safe,  the 
rockmen  proceed  to  remove,  bit  by  bit,  the  huge  mass  of  slate 
lying  between  their  floor  and  the  one  above  it.  Such  a  mass  will 
sometimes  be  sufficient  to  produce  merchantable  slate  worth 
;£io,ooo  or  even  ^15,000,  and  to  give  work  to  a  small  gang  of 
men  for  fifteen  years. 

In  the  plan  (Fig.  359),  the  lines  PP'  are  the  sides  of  the  chambers 
and  also  indicate  the  direction  of  the  "  pillaring."  When  the  slate 
is  taken  away  a  large  chamber  is  left,  and  the  series  of  chambers 
one  above  the  other  forms  a  huge  continuous  inclined  opening 
stretching  down  from  the  surface,  it  may  be,  for  a  distance 
of  several  hundred  yards.  Between  each  two  of  such  openings, 
there  is  the  supporting  pillar,  nearly  if  not  quite  equal  in  size  to 
that  of  the  excavation.  The  consequence  is  that  very  nearly  one- 
half  of  the  available  slate  is  lost  in  the  form  of  pillars ;  much 
again  is  entirely  wasted  in  making  the  preliminary  drivage,  the 
"  roof,"  the  "  widening,"  and  the  "  free  side."  There  is  a  further 
loss  in  getting  the  blocks  arid,  as  we  shall  see  later  on,  in  making 
these  into  marketable  roofing  slates  or  slabs.  Jndeed  it  is 
reckoned  that  even  a  good  "  vein  "  will  yield  only  about  40  per 
cent,  in  the  form  of  blocks,  and  that  two-thirds  of  this  are  wasted 
in  the  subsequent  dressing.  Therefore,  the  slate  miner  does  not 
sell  more  than  one-tenth  to  one-sixth  of  the  slate  rock  which  he 
lays  bare  in  a  chamber,  to  say  nothing  whatever  of  the  loss  in 
the  form  of  pillars,  which  have  to  be  left  in  the  mine  as  perma- 
nent supports. 

There  are  varieties  of  this  method  of  working.  For  instance, 
at  Aberllefenny  in  Merionethshire,*  a  bed  60  feet  thick,  dipping  at 
an  angle  of  70°,  is  worked  by  alternate  pillars  and  chambers  with 
a  much  smaller  loss  in  supporting  rock.  The  pillars  are  from 
24  to  30  feet  long,  and  the  chambers  100  to  187  feet  along  the 
line  of  strike.  Indeed  even  at  Festiniog,  there  are  chambers  at 
Wrysgan  Mine,  where  the  roof  is  very  strong,  more  than  130  feet 
in  length,  whilst  the  pillars  are  only  50  feet. 

At  Angers,  in  France,  the  beds  dip  at  a  high  angle,  and  the 
underground  workings  are  carried  on  like  an  open  quarry 
under  a  strong  roof  of  slate ;  the  floor  is  being  continually 
worked  away  in  steps,  and  an  immense  open  chamber  is  left  with 
perpendicular  sides. 

In  the  French  Ardennes  the  beds  of  slate  are  inclined  at  lower 
angles,  and  in  this  respect  more  resemble  those  at  Festiniog; 
but  the  pillars  run  indefinitely  along  the  strike,  instead  of 
approaching  the  line  of  dip.  The  cross-section  (Fig.  361)  shows 

*  C.  Le  Neve  Foster,  "Notes  on  Aberllefenny  Slate  Mine,"  Trans.  R. 
Geol.  /S'oc.  Cornwall,  vol.  x.  p.  169. 


EXPLOITATION.  315 

these  pillars  A  A,  and  the  chambers  between  them.  The 
attack  of  the  bed  is  made  from  below,  and  not  from  above  as  in 
Wales,  and  the  slate  is  removed  slice  after  slice  parallel  to  the 
bedding.  The  men  stand  upon  the  rubbish,  which  finally  fills  up 
the  chambers  completely.  In  the  figure  the  upper  chamber  is 
exhausted,  the  next  one  is  half  worked  out,  and  in  the  lowest 
only  one  slice  has  been  taken  off. 

This  method  of  mining  is  favoured  by  the  presence  of  natural 
joints,  which  can  be  utilised  for  forming  the  roofs  of  the  chambers 
without  any  cutting. 

In  this  case  the  walls  of  the  excavation  are  supported 
eventually,  not  only  by  the  pillars,  but  also  by  the  rubbish,  and 
other  instances  may  be  found  where  a  filling  up  with  waste  rock 
constitutes  a  feature  of  the  method  of  working.  For  instance,  the 
thick  seam  of  carnallite  or  kainite  at  Stassfurt  is  worked  by  huge 
chambers,  between  which  pillars  are  left.  The  Prussian  Govern- 
ment, fearing  that,  in  spite  of  wide  pillars,  a  "  caving-in  "  may 
possibly  occur,  has  ordered  all  the  excavations  to  be  filled  up. 
The  cheapest  method  of  doing  this  is  by  working  out  chambers  in 
the  bed  of  rock-salt,  lying  geologically  below  the  potash  salts, 
and  using  the  salt  as  stowing.  The  chambers  in  the  rock-salt 
stand  well  without  fear  of  the  roof  giving  way. 

At  the  Wieliczka  salt  mines  it  has  been  found  that  the  natural 
pillars,  originally  supposed  to  afford  ample  support,  are  not  always 
capable  of  preventing  the  roof  from  falling,  and  in  some  places 
they  are  supplemented  by  huge  timber  frames  (Fig.  268),  which 
are  nothing  more  than  "  cogs  "  or  "  pigsties,"  on  a  gigantic  scale. 

A 2.  Pillar  Workings  with  Temporary  Pillars. —  It  is 
naturally  far  more  satisfactory  from  an  economic  point  of  view 
to  leave  as  little  of  a  deposit  as  possible  :  a  larger  output  can 
be  got  from  a  given  working  area  if  everything  is  removed,  and 
it  seems  a  pity  after  a  bed  of  mineral  has  been  discovered,  and 
after  all  the  dead  work  of  sinking  shafts  and  driving  levels 
has  been  accomplished,  to  allow  any  of  the  valuable  material, 
the  very  object  of  the  mining,  to  be  left  behind.  We  therefore 
now  come  to  the  cases  in  which  driving  galleries  and  cutting 
up  the  bed  into  pillars  form  only  a  first  stage  in  the  actual 
exploitation. 

The  most  important  example  in  this  country,  after  coal,  is  the 
mining  of  ironstone  in  the  Cleveland  district.  The  bed  has  an 
average  thickness  of  about  12  feet  (Fig.  43)  where  worked. 
If  the  contour  of  the  country  is  not  suitable  for  bringing  in 
adit  levels,  two  vertical  shafts  are  sunk,  one  of  which  is  shown 
in  Fig.  362.  An  almost  level  road,  the  main  way,  is  driven  out 
with  a  width  of  5  yards ;  drivages  are  put  out,  at  right  angles 
to  it,  at  intervals  of  20  yards,  called  bords,  also  5  yards  wide, 
and  at  distances  of  30  yards  apart  cross-drivages  are  made,  called 
walls.  These  are  only  4  yards  wide.  By  this  system  of  galleries, 


FIG.  362. 

jUULJL 

rar~ 


316  ORE  AND  STONE-MINING. 

the  bed  is  cut  up  into  a  series  of  pillars,  30  yards  long  by  20  yards 
wide,  and  owing  to  the  size  of  the  tunnels  the  quantity  of  ore 
got  out  in  this  preliminary  stage  is  by  no  means  small.  When 
the  bed  has  been  divided  up  in  this  way,  the  work  of  removing  the 
pillars  begins.  As  a  rule,  the  attack  begins  on  pillars  situated 
near  the  boundary,  so  that  whilst  the  first  carving  out  proceeded 
towards  the  boundary,  the  removal  goes  on  in  the  opposite  direction 
— viz.,  towards  the  shaft.  A  place  or  drift  a  b  is  worked  across  the 

pillar  for  a  width  of  2  to  4 
yards,  and  then,  starting 
from  the  drift  a  b,  the  rect- 
angle beyond  it  is  removed 
by  drivages,  called  lifts, 
sometimes  two  in  number, 
sometimes  three,  as  shown 
in  the  figure  and  marked 
i,  2  and  3.  It  may  be 
_  necessary  in  some  cases  to 
leave  a  little  of  the  pillar, 
in  order  to  keep  out  the 
fallen  rubbish  beyond  and 
to  prevent  a  too  sudden  fall 
of  roof.  According  to  circum- 
stances, it  may  be  a  corner 

of  the  pillar  that  is  left,  or  a  narrow  strip  on  one  side.  The 
working  place  is  timbered  during  the  removal  of  the  ironstone, 
and  when  all  has  been  taken  out  the  timber  is  withdrawn  and 
the  roof  allowed  to  fall.  While  the  lifts  i,  2,  3.  are  being  worked 
away,  another  place  c  d  is  being  driven  across  the  pillar,  which 
is  a  preparation  for  another  set  of  lifts  4,  5,  6  ;  lastly,  lifts  7, 
8,  9  are  worked  away,  and  with  the  exception  of  occasional  small 
corners  or  strips,  the  removal  of  the  pillar  is  complete,  and  its 
place  is  taken  by  fallen  rubbish.  The  ironstone  is  got  by  boring 
and  blasting ;  the  holes  are  bored  by  hand  or  by  machine,  and 
gunpowder  is  the  explosive  mostly  used.  The  jumper  employed  and 
the  three  forms  of  mechanical  augers  have  already  been  described. 
Varieties  of  this  method  of  pillar  working  naturally  occur,  but 
they  all  come  back  to  this  main  principle,  when  the  bed  is  of  a 
thickness  which  enables  it  to  be  dealt  with  in  one  operation. 

As  another  example  I  will  take  a  bed  of  alluvial  tin  ore,  to  which 
I  have  already  alluded  in  speaking  of  thje  sinking  of  a  shaft 
through  mud  near  Falmouth  (p.  268). 

The  bed  of  stanniferous  gravel  varied  in  thickness  from  3 
inches  to  7  feet,  but  as  a  rule  it  was  not  thick  enough  for  men  to 
stand  upright  when  at  work  ;  the  maximum  width  was  100  yards. 
It  was  reached  by  a  shaft  D  sunk  through  the  mud  of  the  tidal 
creek,  and  also  by  a  shaft  C  and  level  AA  in  the  hard  slate 
(Figs.  363  and  364).  Main  levels  EE  were  driven  in  the  gravel 


EXPLOITATION 


318  ORE  AND  STONE-MINING. 

bed  20  fathoms  apart,  and  air  levels  GG,  all  strongly  timbered. 
Cross  or  stripping  levels  HH,  14  feet  apart,  were  pushed  out 
from  one  air  level  to  the  other,  and  the  gravel  was  removed 
for  a  distance  of  7  feet  on  each  side,  as  shown  by  the  shading  J. 
The  mud  forming  the  roof  was  allowed  to  fall,  and  fill  up  the 
empty  spaces.  The  gravel  was  wheeled  in  barrows  to  the  main 
levels  EE,  and  conveyed  by  a  railway  to  one  of  the  passes  FF, 
which  led  to  large  bins,  whence  it  could  be  drawn  off  into  waggons 
in  the  main  rock-level  A  A,  and  sent  to  the  shaft. 

Drift  mining,  or  the  working  of  auriferous  alluvial  gravel,  is 
carried  on  in  a  similar  manner.  Old  river  beds  which  carry  gold 
are  common  in  California,  and  especially  in  Sierra  and  Placer 
Counties.  These  beds  once  occupied  the  lowest  ground  of  the 
district,  and  became  covered  over  by  true  lava  flows,  volcanic 
ash  and  mud,  sometimes  also  by  the  deposition  of  pipeclay  and 
infusorial  earth.  The  streams  were  diverted  and  cut  themselves 
new  channels,  which  in  process  of  time  were  so  much  deepened 
as  to  lie  many  hundred  feet  below  the  level  of  the  old  buried 
auriferous  beds.  The  width  and  thickness  of  the  old  gold-bearing 
alluvia  vary  greatly,  as  might  be  expected  from  observing  the 
bed  of  a  river  at  the  present  day,  and  the  gold  is  not  uniformly 
distributed  in  the  gravel.  The  total  thickness  of  the  gold- 
bearing  gravel  may  amount  to  as  much  as  600  feet.  In  drift- 
mining  the  workings  are  confined  to  the  "pay-lead,"  usually  the 
very  bottom  of  the  channel,  varying  from  100  to  150  feet  in  width 
on  an  average.*  Where  there  is  a  rich  gravel  with  $5  to  $8  per 
cubic  yard,  the  leads  may  be  only  50  to  75  feet  wide ;  where 
gravel  with  $2  to  $4  is  being  mined,  they  are  often  300  feet  to 
400  feet  wide. 

By  tracing  the  junction  of  the  underlying  slate  and  the 
volcanic  capping  (Fig.  365!),  an  idea  is  obtained  of  the  run  of  the 
ancient  valley,  and  arrangements  are  made  for  reaching  the  old 
river-bed,  either  by  an  adit  driven  into  the  hillside,  or  by  a  shaft 
sunk  from  the  top.  Working  by  shafts  entails  the  expense  of 
winding  and  pumping,  and  adits  are  therefore  preferred.  In 
fixing  a  position  for  the  adit,  care  is  taken  to  start  it  so  that  it 
will  come  in  a  little  below  the  level  of  the  gold-bearing  gravel, 
and  so  that  it  will  afford  sufficient  tip-room  for  the  waste  material. 
The  adit  of  the  Forest  Hill  Divide  Company,  Placer  County,  is  600 
yards  long,  some  others  are  nearly  a  mile  in  length  before  getting 
underneath  the  old  channel.  When  the  goal  has  thus  been  attained, 
a  level  is  driven  in  the  general  direction  of  the  "  lead,"  or,  roughly 
speaking,  at  right  angles  to  the  first  part  of  the  adit ;  the  whole 
of  this  work  is  carried  on  in  the  slate  or  "  bed-rock,"  in  order 

*  Hammond,  "The  Auriferous  Gravels  of  California,"  California  State 
Mining  Bureau,  Ninth  Annual  Report  of  the  State  Mineralogist,  Sacramento, 
1890.  p.  in. 

t 


EXPLOITATION.  319 

to  save  the  cost  of  timbering  and  repairs,  which  would  be 
considerable  in  the  gravel  itself.  Rises  (upraises,  U.S.A.)  are 
put  up  into  the  gravel  bed,  and,  after  a  preliminary  division  into 


HO  t> 


§•  It's,  sv 

P  3".  a  ;-£? 


" 


frR 

o  fo 


li 


g 

o 

H 


- 


II 


blocks  by  a  series  of  cross  drivages,  the  bed  is  worked  away.  The 
gravel  is  wheeled  to  the  rises  (passes,  chutes,  U.S.A.)  leading  to 
the  main  tunnel,  and  thence  drops  into  waggons  which  are  drawn 
out  by  horses  to  the  surface. 


320  OEE  AND  STONE  MINING. 

It  is  reckoned  in  Placer  County,  California,*  that,  in  the  case 
of  a  mine  producing  250  tons  (or  carloads)  of  gravel  a  day,  the 
total  cost  of  getting,  tramming,  washing  and  agency  is  about 
$1.10,  or  45.  6d.,  per  ton.  The  yield  in  this  region  varies  from 
$ i  to  $10  per  ton  (carload,)  and  may  be  taken  at  $2.50  or  los. 
per  ton  on  an  average. 

The  method  of  working  by  temporary  pillars  is  not  confined  to 
beds  of  small  or  medium  thickness. 

The  lead-bearing  sandstone  at  Mechernich  furnishes  a  good 
example  of  what  can  be  done  in  a  rock  which,  though  far 
from  being  hard,  will  nevertheless  allow  large  excavations  to 
be  made  without  any  timber.  As  has  been  already  mentioned, 
the  bed  of  sandstone  is  sometimes  as  much  as  100  feet  thick. 
Drivages  are  made  in  the  bottom  part  of  the  bed,  about  2  m. 
high  by  2  in.  wide,  and  these  are  followed  by  a  series  of  cross 
drivages,  dividing  the  bed  up  into  a  number  of  square  pillars, 
6  m.  by  6  m.,  or  8m.  by  8  m.,  resembling  the  squares  of  a 
chess-board.  Then,  beginning  at  the  outer  part  of  the  boun- 
dary of  the  sett,  the  miners  proceed  to  remove  the  whole  of  the 
sandstone  from  the  floor  to  the  roof,  and  at  last  let  the  roof  of 
conglomerate  fall  in.  As  a  rule  they  convert  the  space  covered 
by  four  adjacent  pillars  into  one  chamber.  This  is  done  by 
cutting  round  each  of  the  four  pillars  and  gradually  reducing  it 
in  size,  until  at  last  there  is  an  open  space  where  the  four  pillars 
stood,  say  a  square  22  to  24  yards  (20  to  22  m.)  on  the  side,  the 
height  still  being  the  same  as  that  of  the  original  drivages — i.e., 
2  metres.  Standing  upon  the  broken  rock,  the  men  now  attack  the 
roof,  which  they  can  often  get  away  in  layers  of  about  5  feet  in 
thickness,  by  cutting  a  big  groove  round  the  periphery  of  the 
chamber  and  often  putting  in  a  suitable  blast.  The  central  part 
will  then  fall  in  one  mass  breaking  up  as  it  strikes  the  ground. 
A  second  layer  is  taken  off  and  the  chamber  again  heightened 
5  feet.  While  this  work  is  going  on  the  roof  is  sounded  by  being 
struck  with  a  long  pole.  The  miners  learn  by  the  sound  given  out 
whether  the  rock  is  firm  or  not,  and  regulate  their  work 
accordingly.  They  work  upwards  till  they  reach  the  conglomer- 
ate, and  having  cleared  out  all  the  ore  allow  the  roof  to  fall  in. 
It  is  important  that  the  roof  should  fall  in,  because,  as  long  as 
it  remains,  it  throws  its  weight  upon  the  other  adjacent  pillars  ; 
but  when  it  has  come  down,  the  pillars  have  only  to  support  the 
weight  of  the  strata  immediately  above  them.  In  the  direction 
of  the  dip,  the  chambers  are  sometimes  made  larger,  and  six  pillars 
are  taken  instead  of  four.  With  a  very  strong  roof  the  chambers 
may  even  cover  an  area  of  109  yards  by  43  yards  (100  m.  by  40  m.). 

At  Mechernich  the  workings  are  arranged  so  that  the  chamber 
remains  open  until  the  last  moment,  the  roof  not  falling  in  till 

*  "  Bergmannische  Mittheilungen  von  derPariserWeltaustellung,"  1889, 
B.  u.  h.  Zeitung,  1890,  p.  314. 


EXPLOITATION. 


321 


the  completion  of  the  process  of  excavation.  The  sulphur  seams  of 
Sicily  are  wrought  differently.*  The  thick  beds  are  pierced  by 
networks  of  tunnels  superposed  one  above  the  other,  and  the 
workings  are  allowed  to  fall  in.  After  a  time,  when  the  collapse 
is  complete,  the  miners  make  drivages  in  the  mass  of  crushed  and 
broken  pillars,  and  so  reap  a  second  harvest. 

The  details  of  the  mode  of  procedure  are  as  follows :  When  the 
clip  of  the  beds  is  less  than  30°,  one  set  of  tunnels  is  driven  along 
the  strike  and  another  set  along  the  line  of  dip.  The  tunnels  are 
made  8  to  13  feet  (2.5  to  4m.)  wide.  Those  along  the  strike  are 
8  to  13  feet  apart,  and  those  along  the  dip  10  to  16  feet  apart, 
leaving  rectangular  pillars  between  them.  If  the  dip  exceeds 
45°,  tunnels  as  before  are  driven  along  the  strike,  and  these  are 
intersected  by  horizontal  cross  tunnels  running  from  the  roof  to 
the  floor  of  the  deposit.  The  height  and  width  of  these  tunnels 
do  not  as  a  rule  exceed  10  feet  (3111.).  If  the  bed  is  thick  the 
tunnels  are  traced  out  in  superposed  planes,  leaving  a  solid  slice 
of  ground  8  to  10  feet  (2.5  to  3  m.)  thick  between  any  two 
successive  -networks  of  drivages. 

The  first  part  of  the  process  is  now  complete,  and  it  is  followed 
by  the  thinning  of  the  pillars.  Beginning  near  the  boundary  of 
the  mine,  a  tunnel  is  driven  through  a  pillar,  or  two  tunnels  are 
driven  if  it  is  a  big  one.  The  sides  of  the  tunnels  are  cut  away 
gradually,  until  at  last  the  weight  of  the  superincumbent  rock 
breaks  down  what  remains  of  the  pillar;  sometimes  shots  are 
put  in  to  effect  or  hasten  the  fall.  As  much  sulphur  rock  as 
possible  is  taken  out,  and  the  next  pillar  is  treated  in  the  same 
way,  and  so  on,  always  proceeding  from  the  boundary  towards 
the  shaft. 

This  method  of  working  has  been  the  cause  of  the  worst  accidents 
and  of  the  majority  of  the  fires,  especially  when  the  stratum  is 
thick,  and  several  sets  of  tunnels  have  been  driven  one  above  the 
other.  In  some  parts  of  the  Colle  Croce  mines,  Lercara,  there 
have  been  as  many  as  ten  working  horizons  one  above  the  other, 
each  horizon,  or  slice,  being  16  feet  (5  m.)  thick,  and  the  bed  itself 
164  feet  (50  m.).  Sometimes  mines  of  this  kind  have  "  caved  in" 
of  themselves ;  in  other  cases  the  general  breaking  up  and  crushing 
together  has  been  produced  intentionally  by  bringing  down  some 
of  the  lowest  pillars  by  a  few  shots.  During  this  crush  the  heat 
produced  by  the  friction  of  great  masses  of  rock  falling  against 
one  another  is  sufficient  to  make  the  sulphur  take  fire.  The  mine 
is  then  closed,  and  the  fire  eventually  dies  out  for  want  of  oxygen, 
though  there  are  instances  of  fires  going  on  burning  for  more 
than  sixty  years.  When  the  fire  is  supposed  to  be  completely 

*  "  Sui  sistemi  di  lavorazione  impiegati  nelle  solfare  del  gruppo  di 
Colle  Croce  in  Lercara,  e  sui  provvedimenti  da  adottarsi  per  migliorarne  le 
condizioni  di  sicurezza,"  Rivista  del  servizio  minerario  nel  1888,  Florence, 
1890,  pp.  67  to  99. 


322  ORE  AND  STONE-MINING. 

extinguished,  work  is  begun  in  the  broken  mass,  by  driving  a 
series  of  tunnels,  along  much  the  same  lines  as  those  made 
originally  in  the  virgin  bed.  The  tunnels  are  supported  by  walling 
and  timber.  A  similar  network  is  then  made  at  a  level  18  feet 
(5.50111.)  above,  and  in  some  instances  there  are  three  such  sets  of 
levels  in  "  the  broken "  one  above  the  other.  The  tunnels  of 
the  lowest  horizon  are  widened  out,  and  by  means  of  suitable  shots 
the  whole  mass  of  broken  rock  is  made  to  fall  again,  and  of  course 
the  tunnels  disappear.  This  process  of  making  a  network  of  levels 
at  two  or  three  horizons  is  repeated,  and  the  "caving-in"  is 
brought  about  again  until  the  sulphur-bearing  rock  is  exhausted, 
or  so  much  barren  stuff  from  the  roof  is  mixed  with  it  as  to 
make  the  work  unprofitable. 

The  crushes  themselves  have  not  generally  been  accompanied  by 
accidents,  but  work  in  the  broken  ground  has  been  very  fatal. 

For  working  these  deposits,  and  especially  the  thick  ones,  a 
filling-up  method  is  preferable,  and  the  "  ginesi,"  or  residues  from 
the  treatment  of  the  sulphur-rock  in  kilns,  are  ready  at  hand  as 
the  most  convenient  material  for  the  purpose. 

The  filling-up  method  enables  the  sulphur  bed  to  be  worked 
away  completely,  whereas  with  the  method  of  networks  of  drivages 
followed  by  falls,  fully  one-fifth  or  even  one-fourth  of  the  mineral 
is  lost.  Besides,  there  are  fires  and  subsidences  of  the  ground 
causing  fissures  which  let  water  in,  and  therefore  producing  more 
danger  to  the  men  and  also  to  the  adjoining  mines. 

The  Italian  Inspectors  of  Mines  are  of  opinion  that  poor 
beds,  which  could  not  be  wrought  profitably  by  the  filling-up  pro- 
cess, may  in  certain  exceptional  cases  be  worked  by  the  old  method, 
because  the  firmness  of  the  rock  increases  as  the  percentage  of 
sulphur  diminishes.  However,  they  limit  the  number  of  super- 
posed working  floors  to  three,  and  stipulate  that  an  upper  floor 
shall  be  entirely  worked  out  before  a  lower  one  is  taken  away. 

It  is  estimated  that  in  the  year  1889*  only  43  per  cent,  of  the 
sulphur  produced  in  Sicily  came  from  virgin  ground,  and  that  all 
the  rest  was  obtained  from  drivings  among  broken  pillars  and 
workings  that  had  "  caved  in." 

B.  Longwall. — Having  discussed  the  various  ways  of  work- 
ing a  bed  by  permanent  or  temporary  pillars,  we  now  come  to 
the  so-called  longwall  method.  In  this  case  there  is  no  pre- 
liminary carving  out  into  pillars,  but  the  mineral  is  worked  away 
in  long  faces,  whence  the  name  applied  to  the  system. 

A  typical  case  is  found  in  the  workings  for  copper  shale  in 
the  Mansfeld  district,  Germany.t 

*  Bivista  del  servizio  minerario  nel  1889,  p.  76. 

f  This  account  of  the  workings  of  the  copper  shale  is  based  upon  the 
description  in  the  pamphlet,  ' '  Der  Kupf  erschief  erbergbau  und  der  Hiitten- 
betrieb  zur  Verarbeitung  der  gewonnenen  Minern  in  den  beiden  Mansfelder 
Kreisen  der  Preuss.  Provinz  Sachsen,i889,"  and  upon  personal  observations. 


EXPLOITATION.  323 

The  bed,  as  already  mentioned,  is  usually  from  3  to  5  inches 
thick,  but  it  makes  up  for  its  thinness  and  poverty  by  its 
uniformity  of  yield,  at  all  events  compared  with  a  mineral  vein. 

It  is  worked  for  a  distance  of  n  miles  (18  kil.)  along  the  strike, 
and  the  present  plan  of  operations  consists  in  having  a  set  of 
shafts  for  every  2\  miles  (4  kil.),  that  is  to  say  a  set  of  shafts 
serves  for  the  workings  ij  mile  (2  kil.)  on  each  side  of  it.  The 
great  difficulties  encountered  in  sinking  shafts  through  the  watery 
measures  above  the  copper  shale  have  led  to  the  adoption  of  the 
system  of  driving  out  long  crosscuts  to  intersect  the  bed  on  the 
floor  side.  These  crosscuts  can  be  driven  with  speed  by 
machine-drills,  and  various  mechanical  means  are  available  for 
haulage.  On  the  other  hand,  in  spite  of  the  considerable  im- 
provements which  have  been  introduced  into  shaft  sinking  by  the 
Kind-Chaudron  process,  much  time  is  required  and  a  very  heavy 
expenditure  of  capital.  There  is  also  the  consideration  that  if 
the  shafts  were  on  the  roof  side,  crosscuts  would  have  to  be 
driven  at  the  level  of  the  adit  in  order  to  get  rid  of  the  water. 
These  crosscuts  would  sometimes  traverse  the  troublesome 
gypseous  measures,  full  of  unknown  pools,  and  they  would  be 
above  the  worked-out  bed  of  copper  shale  and  therefore  be  subject 
to  slight  sinkings  of  the  ground.  Crosscuts  in  the  measures 
below  the  copper  shale  do  not  present  these  difficulties.  Of 
course  it  would  be  possible  to  lift  the  water  to  the  surface  and  not 
discharge  it  into  the  adit.  This  would  entail  extra  expense  for 
pumping,  and  in  this  particular  instance  there  is  the  further 
objection  that  the  water  is  so  salt  that  it  cannot  be  discharged 
without  damage  into  any  small  brook.  It  therefore  becomes 
necessary  to  conduct  it  into  a  river  like  the  Saale,  too  big  to  be 
seriously  affected  by  the  briny  stream  from  the  mines. 

The  workings  are  arranged  in  a  succession  of  floors  taken 
exactly  62.7  m.  apart.  This  distance  is  the  equivalent  of  30 
German  fathoms,  and  is  68J  yards.  To  save  expense,  crosscuts 
are  put  out  from  the  shaft  at  every  second  floor,  that  is  to  say, 
they  are  vertically  125.4  metres  one  below  the  other.  Drivages 
along  the  strike  are  pushed  out  on  each  side  of  the  crosscut, 
and  by  putting  up  "  rises "  each  level  is  brought  into  com- 
munication with  the  one  above.  Intermediate  tunnels  are  then 
driven  along  the  shale  from  a  point  midway  between  the  two 
crosscuts,  and  the  bed  is  now  traversed  by  levels  along  the 
strike,  at  intervals  of  62.7  metres  vertically,  which  constitute  the 
main  working  roadways.  As  the  dip  is  about  5°  or  6°,  the  distance 
from  one  main  roadway  to  the  next  is  as  much  as  600  to  800 
yards,  and  constitutes  a  long  working  face  or  "longwall."  In 
Fig.  366,  A  B  represents  a  main  level,  and  C  D  the  next  one 
below  it.  E  F  is  the  working  face,  which  is  cut  away  gradually 
till  it  becomes  E'  F',  and  then  E"  F",  and  so  on. 

This  working  face  is  occupied  by  a  string  of  miners,  in  fact  as 


324 


ORE  AND  STONE  MINING. 


many  are  employed  as  the  space  will  accommodate.  The  workman 
lies  upon  his  left  side,  reposing  upon  a  shoulder-board  and  a  leg- 
board.  The  latter  is  strapped  to  the  thigh,  but  the  former  is  free, 
and  is  shifted  as  required.  The  work  comprises  the  following  suc- 
cessive operations  —  (i)  Holing  with  the  pick  ;  (2)  wedging  down 
the  copper  shale  ;  (3)  blasting  down  the  roof  ;  (4)  stowing  the 
deads.  The  holing  is  done  in  the  lowest  part  of  the  bed  of 
copper  ore,  along  the  hard  and  smooth  floor.  Enough  of  the  roof 
is  taken  down  to  give  the  miner  just  room  enough  to  do  his  work. 
It  is  best  to  have  as  much  as  23  inches  (58  cm.),  but  if  there  is  a 
convenient  smooth  plane  of  bedding  for  forming  the  roof  at  a 
height  of  i8J  inches  (47  cm.)  no  more  is  taken  down  ;  indeed,  in 
some  exceptional  cases  the  height  is  only  15!  inches  (40  cm.). 


FIG.  366. 


PLAN 


g^ggg|  )^>^r  i^^^jjji^v^ff^p^^ 


The  barren  rock  serves  as  material  for  stowing  or  filling  up,  and 
as  the  quantity  is  more  than  sufficient  for  this  purpose,  some  of  it 
has  to  be  drawn  up  to  the  surface. 

It  is  necessary  to  have  roads  for  taking  away  the  ore  from 
the  face,  and  they  are  formed  by  reserving  passages  in  the 
stowing  and  by  blasting  down  the  roof,  so  as  to  give  suffi- 
cient height.  These  divisional  roads  are  shown  by  the  letters 
a  b,  c  d.  e  f,  &c.  The  interval  between  them  varies  from  50 
to  1 20  yards;  and  in  all  cases  there  are  diagonal  branch  roads 
leading  from  the  railroad  towards  the  face,  which  is  finally 
reached  by  the  so-called  "  Fahrten."  They  are  low  passages  in 
the  stowing,  along  which  the  ore  is  dragged  by  boys  in  little  carts. 
The  diagonal  roads,  however,  are  made  5  feet  high  by  blasting 
down  the  roof.  Owing  to  the  small  scale  of  the  diagram  it  is 
impossible  to  show  all  the  branch  roads  connecting  the  working- 
face  with  the  levels  running  along  the  strike.  The  direction 
given  to  the  working  face  is  a  matter  of  importance,  for  it 


EXPLOITATION.  325 

•enables  the  amount  of  pressure  coming  upon  the  rock  to  be  varied. 
The  pressure  is  felt  most  when  the  face  is  parallel  to  the  strike 
and  the  working  carried  up  to  the  rise ;  it  is  felt  least  when  the 
face  is  parallel  to  the  strike  and  the  work  is  proceeding  down- 
wards. If  the  face  runs  in  a  direction  parallel  to  the  line  of  dip, 
the  pressure  is  intermediate  in  amount.  Therefore  by  regulating 
the  line  of  the  face,  the  mining  authorities  have  it  in  their  power 
to  cause  what  amount  of  pressure  they  think  most  desirable  for 
the  work.  As  a  rule  the  line  chosen  for  the  working  face  lies 
somewhere  between  the  line  of  strike  and  the  line  of  greatest 
dip. 

In  new  ground  in  the  deeper  workings,  holing  with  the  pick 
is  a  very  laborious  operation,  and  has  on  that  account  been  given 
up  •  in  such  places  the  shale  is  got  by  blasting.  After  the  lapse 
of  three-quarters  of  a  year  or  a  year  and  a  half,  when  a  large  area 
has  been  worked  away  and  the  roof  begins  to  subside  upon  the 
stowing,  pressure  is  felt  on  the  working  face  and  the  holing  be- 
•comes  much  easier.  In  order  to  bring  about  this  state  of  affairs 
as  soon  as  possible,  Jager  drills  worked  by  compressed  air  have 
been  employed  in  getting  the  ore. 

The  Mansfeld  longwall  has  the  peculiarity  that  more  deads 
are  produced  than  can  be  stowed  away  in  the  excavations  ;  these 
are  therefore  packed  very  full  and  the  amount  of  subsidence  is 
not  great. 

In  some  other  varieties  of  the  longwall  method  there  is  no 
stowing  at  all  and  the  roof  is  allowed  to  fall  in,  or  the  amount 
of  rubbish  produced  by  the  seam  is  insufficient  to  fill  up  the  empty 
spaces.  There  is  also  a  diversity  of  practice  with  regard  to  the 
direction  in  which  the  longwall  face  is  carried,  sometimes  the 
seam  is  worked  by  longwall  outwards — that  is  to  say,  the  face 
is  carried  from  the  neighbourhood  of  the  shaft  towards  the 
boundary  of  the  property,  in  others  it  is  carried  "  homewards " 
from  the  boundary  towards  the  shaft. 

2.  VEINS. — In  the  case  of  a  vein,  an  exploratory  pit  is 
often  sunk  upon  it  for  20  or  30  fathoms,  and,  if  the  indica- 
tions found  in  driving  out  levels  warrant  further  prosecu- 
tion of  the  mine,  a  first  working  shaft  is  put  down  to 
intersect  the  lode  at  a  depth  of  100  fathoms  or  more  from  the 
surface.  Crosscuts  are  then  driven  out  at  intervals  of  10,  15, 
or  20  fathoms  to  reach  the  lode  as  shown  in  Fig.  367,  which 
represents  a  section  at  right  angles  to  the  line  of  strike. 
Sometimes  the  main  shafts  are  carried  down  all  the  way  along 
the  dip  of  the  vein,  though  perpendicular  shafts  have  the 
advantage  of  being  better  suited  for  quick  winding  and 
cheap  pumping,  to  say  nothing  of  the  rapid  ascent  and  descent 
of  the  miners  in  cages.  If  an  inclined  shaft  appears  to  be 
advisable,  great  care  should  be  taken  to  sink  it  in  a  straight 
line.  The  worst  shafts  are  the  crooked  ones  so  common  in 


326 


ORE  AND  STONE-MINING. 


Cornwall,  vertical  perhaps  for  the  first  hundred  fathoms  until  the 
lode  is  struck,  and  then  carried  downwards  along  its  varying 
dip. 

Whatever  kind  of  shaft  is  adopted,  levels  are  driven  out  along 
the  strike  of  the  lode,  as  shown  in  the  longitudinal  section  (Fig.  368), 
in  the  hope  of  meeting  with  valuable  ore-bodies  such  as  are 
represented  by  the  stippled  portions  of  the  figure.  For  the 
purpose  of  affording  ventilation,  and  still  further  exploring  the 
ground  and  working  it,  intermediate  shafts,  called  winzes 
(Cornwall),  or  sumps  (North  Wales),  are  sunk  in  the  lode  from 
one  level  to  the  other.  In  some  cases  the  communicating  passage 
is  excavated  upwards,  or,  in  other  words,  the  miner  "  puts  up  a 


FIG.  367. 


FIG.  368. 


SOUTH. 


WEST. 


rise."  When  the  communication  is  complete,  there  is  no  differ- 
ence whatever  between  a  rise  and  a  winze. 

On  looking  at  the  longitudinal  section  (Fig.  368),  which  may  be 
regarded  as  representing  a  common  state  of  things,  it  will  at  once 
be  remarked  that  only  certain  parts  of  the  vein  are  valuable. 
When  dealing  with  a  bed  or  seam,  we  constantly  find  that  the 
whole  area  covered  by  it  can  be  worked  away  profitably.  With 
a  lode  this  is  the  exception,  and  therefore  the  problem  of  exploit- 
ation is  not  the  same  in  the  two  cases.  The  vein-miner  has  to 
remove  portions  of  a  sheet-like  deposit  usually  dipping  at  a  high 
angle,  and  the  bed-miner  to  excavate  the  whole  of  a  sheet-like 
deposit  lying  frequently  nearly  horizontal.  The  un worked  por- 
tions of  the  lode  serve  to  support  the  hanging  wall,  and  form  in 
this  way  the  equivalent  of  irregular  pillars. 

The  actual  mode  of  removing  the  valuable  part  of  the  lode 
itself  depends  a  great  deal  upon  circumstances — viz.,  its  width,, 
the  nature  of  its  contents,  and  that  of  the  walls  or  enclosing 
rock ;  but  the  methods  of  working  may  generally  be  brought 


EXPLOITATION. 


327 


under  one  of  two  heads — viz.,  underhand  stoping  or  overhand 
stoping.  The  word  "  stope  "  is  equivalent  to  step,  and  the  term 
"  stoping  "  means  working  away  any  deposit  in  a  series  of  steps. 
Underhand  or  bottom  stopes  are  workings  arranged  like  the 
steps  of  a  staircase  seen  from  above,  whilst  overhand  or  back 
stopes  are  like  similar  steps  seen  from  underneath.  Both 
methods  have  their  advantages  and  disadvantages,  and  both  are 
largely  used. 

We  will  first  take  underhand  stoping,  as  this  is  the  older 


FIG.  369. 
W//////MMW/////// 


FIG.  371. 


method.  In  the  old  days  the  miner  began  in  the  floor  of  the  level 
(Fig.  369),  and  sank  down  a  few  feet,  removing  the  part  i ;  he 
followed  with  2,  3,  4,  &c.,  until  the  excavation  finally  presented 
the  appearance  shown  in  Fig.  370.  Any  valueless  rock  or  mineral 
was  deposited  upon  platforms  of  timber  (stidls),  and  the  ore  was 
drawn  up  into  the  level  by  a  windlass.  One  great  disadvantage 
of  this  method  was  the  cost  of  winding  up  the  ore  and  water  by 
hand  labour.  At  the  present  day  the  disadvantage  would  not  be 
so  great,  because  power  is  so 
easily  conveyed  to  underground 
winches  by  compressed  air  or  elec- 
tricity. There  always  remains, 
however,  the  necessity  of  pro- 
viding much  timber  for  the  stulls, 
if  there  is  a  large  quantity  of 
worthless  stuff  in  the  vein,  or  if 
the  sides  are  weak.  The  advan- 
tages are  that  ore  can  be  worked 
away  as  soon  as  a  level  is  driven, 

that  the  men  are  always  boring  downwards,  and,  lastly,  that  the 
ore  can  be  carefully  picked  after  it  is  broken,  without  fear  of  any 
valuable  particles  being  lost. 

A  more  economical  method  of  working  by  underhand  stopes, 
and  one  largely  employed  in  Cornwall  at  the  present  day,  consists 
in  reserving  any  attack  upon  the  ore-ground  until  a  lower  level 
has  been  driven.  A  connection  is  then  made  between  the  two 
levels  by  sinking  a  winze  from  the  upper  one,  or  by  putting  up 
a  rise  from  the  lower  one. 

The  work  of  stoping  is  commenced  from  the  two  upper  ends  of 


328 


ORE  AND  STONE-MINING. 

FIG.  372. 


EAST  EH N B  OU NDA RY 

GREAT        CROSS       COURSE 


EXPLOITATION. 


329 


373- 


this  intermediate  shaft,  and  the  lode  is  removed  in  a  succession 
of  steps,  the  workings  assuming  the  appearance  exhibited  in  Fig. 
371.  The  steps  are  gener- 
ally made  steep,  so  that 
the  ore  may  readily  roll 
down  into  the  winze,  and 
so  that  the  boreholes  may 
do  better  execution :  but 
these  steep  stopes  are 
dangerous  if  a  man  hap- 
pens to  slip  and  fall.  The 
huge  open  chasms  left  by 
the  removal  of  a  wide  lode 
in  this  way  are  also  a 
source  of  danger,  for 
there  is  always  a  risk  of 
falls  of  rock,  and  from 
places  which  cannot  easily 
be  examined. 

Figs.  372  and  373  ex- 
plain the  general  arrange- 
ments for  working  Dol- 
coath,  the  largest  tin  mine 
in  Cornwall.  The  lode, 
after  producing  copper 
ores  for  a  considerable 
depth,  changed  its  char- 
acter and  became  rich  in 
tin.  The  workings  for  tin 
are  confined  almost  en- 
tirely to  the  granite.  The 
section  (Fig.  373)  shows 
that  the  main  shaft  of  the 
mine  is  at  first  vertical  and  then  carried  down  on  the  dip  of  the 

lode.  The  mine  is  now  consider- 
ably deeper  than  indicated  in  the 
figures,  but  the  method  of  work- 
ing remains  the  same. 

The  process  of  overhand 
stoping  is  precisely  the  reverse 
of  that  which  has  been  des- 
cribed :  the  work  is  commenced 
from  a  rise  (Fig.  374,  A),  or 
better,  from  the  two  ends  of  a 
winze  (Fig.  374,  B).  As  soon 
as  the  men  have  excavated  a 

sufficient  height  of  the  level,  they  put  in  strong  pieces  of  timber 
from  wall  to  wall  (stempels,  stull-pieces),  and  cover   these  cr OSS- 


FIG.  374. 


330 


CUE  AND  STONE-MINING. 


pieces  with  boards  or  poles,  and  throw  down  the  rubbish  upon 
the  platform  (stull,  bunning)  thus  formed.  In  the  midst  of  the 
rubbish,  chimney-like  openings  (mills,  passes)  are  reserved,  lined 
with  boards  or  dry  walling,  and  closed  at  the  bottom  with  shoots 
provided  with  doors.  The  ore  is  thrown  into  these  passes,  which 


FIG.  375. 


FIG.  376. 

\\X\\\\x\\\\\\\\\\\  \ 


FIG.  377- 


are  tapped  when  necessary.     The  ore  falls  into  the  tram-waggon 
placed  ready  to  receive  it. 

Fig.  375  is  a  transverse  section,  showing  the  rubbish  resting 
on  the  stulls.  This  may  be  called  the  typical  mode  of  stoping, 
when  the  lode  affords  enough  rubbish  for  the  men  to  stand  on, 
and  to  keep  them  close  to  the  rock  they  are  attacking.  Very 
often  such  is  not  the  case,  and  the  whole  of  the  lode  has  to  be  sent 

up  to  the  surface  for  treatment.  If 
the  walls  are  firm,  a  stull  is  put  in, 
and  a  sufficient  heap  of  broken  ore  is 
left  upon  it  to  give  the  men  good 
standing  ground  ;  the  excess  is  thrown 
over  the  ends  of  the  stull,  or  the  great 
heap  is  tapped  by  cutting  a  hole  in 
the  supporting  platform  and  letting 
a  quantity  of  ore  run  down  into  the 
level. 

Another  method  consists  in  putting 
in  temporary  stages  or  platforms 
upon  which  the  men  stand  to  do  their 
work,  whilst  the  excavation  is  left  as 
an  open  space  (Fig.  376).  This  mode 
of  working  is  incompatible  with  weak 
walls.  If  a  lode  does  not  afford  rubbish  enough  for  completely 
filling  up  the  excavated  space,  or  if  it  is  too  narrow  for  the  men 
to  do  their  work  comfortably,  one  of  the  walls  may  be  cut  into  and 
blasted  down  (Fig.  377),  in  order  to  give  the  men  a  firm  bed  of 
rubbish  to  stand  on  while  at  work,  and  to  prevent  any  chance  of  a 
collapse  of  the  mine.  In  certain  special  cases  rubbish  is  sent  down 
from  the  surface  to  fill  up  the  excavations. 


EXPLOITATION.  331 

The  advantages  of  overhand  stoping  are — that  the  miner  is 
assisted  by  gravity  in  his  work,  that  no  ore  or  rock  has  to  be 
drawn  up  by  hand  labour,  and  that  less  timber  is  required.  On 
the  other  hand,  the  miner  is  always  menaced  by  falls  of  the  roof 
of  his  working  place  ;  but  as  he  is  close  by,  he  can  constantly  test 
the  solidity  of  the  roof  and  sides  by  sounding  them  with  his 
sledge.  If  the  rock  rings  clearly  he  feels  safe,  but  if  it  emits 
a  dull  hollow  sound  he  knows  that  it  must  be  taken  down  at 
once,  or  be  supported  in  some  way.  A  last  disadvantage  of 
overhand  compared  with  underhand  stopes,  is  the  chance  of 
valuable  particles  of  ore  being  lost  in  the  rubbish  ;  but  this  loss 
can  be  prevented  by  laying  down  planks  or  sheets  of  iron  while 
the  lode  is  being  broken  down. 

When  very  wide  lodes  have  to  be  worked,  recourse  is  often 
had  to  a  filling-up  method,  and,  indeed,  such  a  method  becomes 
imperative  if  the  sides  are  weak.  The  great  lode  at  the  famous 
Van  Mine,  in  Montgomeryshire,  once  the  premier  lead  mine 
of  the  United  Kingdom,  had 

to  be  worked  in  this  fashion,        ^  FlG-  37&- 

and  as  the  work  was  carried 
out  very  carefully  and  sys- 
tematically, no  better  example 
of  the  method  can  be  chosen. 

The  lode  is  evidently  a  fis- 
sure vein  as  it  cuts  across  the 
planes  of  bedding  and  of 
cleavage  of  the  adjacent  slate 
rock.  It  is  composed  of  three 
parts :  the  flucan  or  soft  lode 
B  (Fig.  378),  the  bastard  lode 
C,  and  the  regular  lode  E. 
The  flucan  consists  of  clay 
and  soft  broken  slate.  The 
bastard  lode  is  a  mass  of  slate  rock,  4  or  5  fathoms  wide,  between 
the  flucan  and  the  regular  lode ;  it  is  much  softer  than  the  true 
country,  and,  though  intersected  by  numerous  small  strings  of 
galena,  is  rarely  rich  enough  to  be  worked.  The  regular  lode  consists 
of  masses  of  slate  traversed  by  veins  of  galena,  or  it  is  a  breccia  of 
fragments  of  slate  cemented  together  by  quartz,  galena  and  blende. 
The  regular  lode  was  at  times  as  much  as  48  feet  (14.60  m.)  wide, 
and  if  the  excavation  formed  by  the  removal  of  such  a  quantity  of 
rock  had  been  left  open,  the  hanging  wall  would  speedily  have 
fallen  in,  and  indeed  even  during  the  progress  of  the  work  the 
men  would  have  been  exposed  to  very  great  danger.  A  filling-up 
method  was  therefore  adopted,  and  as  soon  as  the  ore  had  been 
removed  the  open  spaces  were  packed  with  rubbish. 

Crosscuts  were  driven  out  at  vertical  intervals  of  about  1 5  fathoms 
to  reach  theflucan  B,  which  was  chosen  for  driving  a  preliminary 


332  ORE  AND  STONE-MINING. 

east  and  west  level  on  account  of  its  softness.  This  preliminary 
level  enabled  the  regular  lode  to  be  reached  very  quickly  in  several 
places  by  short  crosscuts,  from  which  the  first  level  in  the  lode 
was  pushed  out  east  and  west. 

The  next  process  consisted  in  stripping  away  both  sides  of  the 
level,  as  far  as  the  footwall  on  the  north  and  the  bastard  lode 
on  the  south,  unless  the  latter  happened  to  be  productive,  in 
which  case  it  likewise  was  excavated.  This  left  a  space  about 
7  feet  high,  which  was  at  once  filled  with  deads,  save  a 
working  level  reserved  in  the  middle,  which  was  properly  secured 
with  timber.  Endeavours  were  always  made  to  keep  this  level  as 
straight  as  possible,  so  as  to  facilitate  the  tramming.  The  letter 
H  in  Fig.  378  represents  this  working  level.  Upon  its  com- 
pletion the  preliminary  level  became  superfluous ;  the  timber 
was  drawn  out  and  allowed  to  crush  together,  as  shown  in  the 
lower  part  of  the  figure. 

In  the  meantime,  starting  from  the  level  above,  winzes  were 
sunk,  20  or  30  fathoms  apart,  in  the  flucan  or  in  the  lode 
itself,  if  the  flucan  happened  to  be  too  far  away  from  the  produc- 
tive part.  The  winzes  served  not  only  for  ventilation,  but  also 
as  shoots  for  the  rubbish  used  in  filling  up ;  they  were  called 
passes,  I  (Fig.  378).  They  were  carefully  timbered  and  divided 
into  two  compartments :  one  was  used  as  a  passage  for  the  rub- 
bish, the  other  was  provided  with  ladders,  and  formed  a  foot- 
way, besides  affording  access  to  the  other  compartment,  in  case 
it  became  choked  with  the  waste  rock  shot  clown  it. 

As  soon  as  arrangements  for  supplying  the  deads  were  complete, 
stoping  was  begun.  The  height  taken  off  in  each  stope  varied, 
according  to  the  firmness  of  the  lode,  from  2  to  6  feet,  and  when 
the  ore  was  removed  the  excavation  wras  packed  with  rubbish 
(D)  drawn  down  from  the  nearest  pass,  such  as  I  (Fig.  378), 
and  wheeled  in  a  barrow  to  the  place  where  it  was  wanted.  As 
the  passes  were  made  at  close  intervals,  the  amount  of  wheeling 
was  very  little.  The  broken  ore  was  thrown  down  into  a  pass  or 
mill,  K,  whence  it  could  be  drawn  off  at  pleasure  into  a  waggon. 
The  ore-passes  were  of  the  same  size  as  the  winzes  sunk  for 
letting  down  the  rubbish,  and  were  timbered  and  divided  into 
two  compartments  in  the  same  way. 

The  lode  itself  furnished  enough  rubbish  to  fill  up  about  one- 
third  of  the  excavation  ;  waste  rock  was  likewise  obtainable  from 
workings  in  dead  ground,  such  as  crosscuts,  and  the  preliminary 
or  permanent  levels  ;  and  finally  slate  was  quarried  at  the  surface, 
shot  down  special  shafts,  and  trammed  through  a  level  such  as  P, 
and  a  crosscut  N  and  level  H,  to  any  special  pass  where  it  was 
required.  To  prevent  any  loss  of  ore  among  the  loose  stones  used 
for  filling  up  (stowing),  it  was  usual  to  spread  over  the  top  of  the 
rubbish  a  layer  of  soft  flucan  for  a  depth  of  a  few  inches,  and  when 
the  lode  had  been  stoped  away  to  the  required  height,  this  floor 


EXPLOITATION. 


333 


was  shovelled  into  the  ore-passes  and  went  to  the  dressing  floor 
with  the  rest  of  the  stuff.  It  was  found  cheaper  and  better  to 
dress  a  few  extra  tons  of  stuff  than  to  pay  for  laying  down  boards 
or  sheets  of  iron  to  catch  the  fine  ore. 

Slice  after  slice  was  taken  off  in  this  way,  and  the  long  working 
face  formed  by  the  roof  of  the  stopes  corresponded  in  some  measure 
to  a  lorigwall  face  in  bed  mining.  On  arriving  within  12  feet  of 
the  old  workings  above,  packed  with  rubbish,  it  w^as  unadvisable 
to  make  openings  of  the  full  width  of  the  lode,  and  the  ore  was  got 
by  crosscuts.  A  level  was  driven  along  the  strike  in  the  middle  of 
the  lode,  or  on  one  side  if  more  convenient ;  crosscuts,  from  5  to  8 
feet  wide,  were  started  from  each  side  of  it,  and  driven  north  and 
south  to  the  footwall  and  hanging  wall  respectively,  the  ground 
being  supported  by  strong  props  of  timber.  The  lode  standing  on 
the  sides  of  the  crosscut  was  then  removed  by  a  series  of  cross 
drivages  similar  to  the  original  crosscut,  only,  as  one  side  was  free, 
the  work  was  much  less  expensive,  costing  abont  ^4  per  fathom 
instead  of  £10.  The  empty  spaces  were  packed  with  waste  to 
the  top,  and  as  much  of  the  timber  was  drawn  away  as  could  be 
removed  with  safety. 

When  the  lower  half  of  the  1 2 -feet  slice  had  been  taken  away 
in  this  fashion  by  a  series  of  short  contiguous  cross  drivages, 
another  level  was  driven  along  the  strike  above  the  old  one  which 
had  been  filled  with  rubbish.  Crosscuts  similar  to  the  ones  below 
were  driven,  save  that  spilling  had  to  be  resorted  to,  as  the  roof 
was  formed  of  the  deads  of  the  earlier  workings.  Whilst  this 
work  was  going  on,  the  miners  could  recover  any  pieces  of  timber 
which  had  been  left  in  the  midst  of  the  rubbish  used  for  stowing 
the  lower  half  of  the  slice.  The  legs  or  forks  were  always  put  in 
with  the  large  end  uppermost,  and  could  be  drawn  up  by  putting  a 
chain  round  the  top  and  applying  a  lever.  As  soon  as  the  upper 
half  of  the  i2-feet  slice  had  been  taken  off  by  these  cross  drivages, 
the  working  level  H  above  it  was  filled  up  and  abandoned. 

The  block  of  lode  1 5  fathoms  high  was  thus  removed  entirely, 
and  its  place  filled  by  rubbish ;  consequently  there  was  no  danger 
of  the  walls  falling  in  and  of  the  mine  collapsing.  No  high  openings 
were  made  during  the  progress  of  the  work,  so  the  roof  and  sides 
could  be  sounded  and  examined  without  scaffolding ;  any  loose 
pieces  could  be  taken  down  at  once,  and  there  was  little  fear  of 
their  falling  unawares  upon  the  miners. 

Before  a  block  was  completely  stoped  away,  the  so-called  perma- 
nent level  at  the  bottom  had  to  be  prepared,  in  order  to  furnish  a 
road  for  conveying  deads  to  the  block  beneath.  Crosscuts,  N, 
were  pushed  out  from  the  level  H,  at  intervals  of  20  or  30 
fathoms,  to  a  distance  of  10  fathoms  beyond  the  flucan,  and  "  ends  " 
were  driven  east  and  west  till  they  met  and  formed  a  continuous 
gallery,  P.  Rails  were  laid  and  the  road  was  ready  for  use. 

Several    men  were    kept    constantly  employed    at    a  quarry 


334 


ORE  AND  STONE-MINING. 


.adjoining  the  mine  for  obtaining  slate,  which  was  trammed  to 
and  shot  down  one  of  the  two  special  rubbish  shafts.  These  could 
be  tapped  at  the  adit,  and  the  supplies  were  conveyed  by  tram- 
roads  and  other  special  shafts,  used  as  shoots,  to  the  places  where 
they  were  required.  Excepting  the  first  two  rubbish  shafts  from 
the  surface,  no  shoots  were  made  more  than  15  fathoms  deep, 
because  it  was  found  by  experience  that  the  timber  was  broken  up 
very  quickly  by  the  fall  of  the  stuff  when  they  were  deeper.  The 
bottom  of  one  shoot  was  always  near  the  mouth  of  the  next,  so 
that  the  rubbish  never  had  to  be  trammed  far;  and  in  some 
instances  the  shoots  were  so  near  that,  by  fixing  a  few  planks 
in  a  sloping  direction,  the  waste  rock  ran  directly  from  one  to 
the  other. 

I  have  entered  somewhat  into  detail  in  this  case,  because  wide 
lodes  with  weak  wralls  have  often  given  much  trouble,  when  the 
.attempt  has  been  made  to  work  them  with  the  use  of  timber 


FIG.  379. 


FIG.  380. 


supports.  The  amount  of  timber  required  at  the  Van  Mine  was 
small,  and  many  of  the  pieces  were  used  over  and  over  again. 
Another  advantage  in  this  particular  case  was  the  certainty  that 
no  ore  was  lost  or  left  behind ;  for  although  money  was  sometimes 
spent  in  breaking  down  poor  parts  of  the  lode  to  make  sure  of  not 
missing  any  lead  ore,  the  barren  rock  could  be  utilised  for  filling, 
instead  of  drawing  supplies  from  quarries  at  the  surface. 

At  the  Van  Mine  the  lode  was  firm  enough  to  allow  the  whole 
width  to  stand  without  supports  during  the  time  a  stope  was  carried 
along,  except  in  the  case  of  the  two  last  slices  at  the  top  of  a  block. 
These,  as  we  have  seen,  were  taken  off  by  a  succession  of  conti- 
guous crosscuts.  When  a  lode  is  wide  and  too  weak  to  stand  open 
with  safety  for  its  whole  width,  the  crosscut  method  may  be 
applied  from  the  beginning,  instead  of  confining  it  to  the  last 
slices. 

The  method  is  illustrated  by  Figs.  379  and  380.  The  lode  is 
removed  in  successive  horizontal  slices,  A  B  C  D  E,  beginning 
at  the  bottom,  and  for  each  slice  a  level,  L,  is  driven,  either  wholly 
in  the  lode,  or  partly  or  entirely  in  the  country  ;  from  this  level, 


EXPLOITATION. 


335 


FIG.  381. 


crosscuts  are  put  out  6  or  8  feet  wide,  as  shown  in  the  plan 
(Fig.  380).  These  are  regularly  timbered,  according  to  the  necessi- 
ties of  the  case,  and  when  No.  i  is  completed,  No.  2  is  begun,  and 
the  rubbish  from  No.  2  thrown  into  the  empty  space  of  No.  i  cross- 
cut. If  the  quantity  is  insufficient,  deads  are  brought  in  from  the 
surface  or  from  exploratory  workings  in  worthless  rock  in  the 
neighbourhood.  Sometimes  the  crosscuts  are  not  driven  side  by 
side,  but  i  and  5  may  be  driven  first,  leaving  2,  3,  and  4  as  a  solid 
pillar ;  then  3  is  worked  away,  and  finally  2  and  4  between  the 
timber  and  rubbish  on  each  side.  The  greater  part  of  the  timber 
can  be  recovered  when  the  next  slice  above  is  taken  off,  as  the 
props  are  put  in  with  their  small  ends  downwards,  and  can  be 
drawn  up  with  a  lever.  M  (Fig.  379)  is  a  level  reserved  in  the 
deads  for  traffic  and  ventilation.  This  method  of  working  is 
applicable  not  only  to  lodes,  but  also  to  irregular  masses. 

The  mode  of  working  the  soft  ore-bodies  such  as  are  met  with 
in  the  Comstock  lode,  in  the  Eureka-Bichmond  mines,  Nevada, 
and  at  Broken  Hill  in  New  South  Wales, 
has  been  already  described  in  the  chapter 
upon  timbering.  The  excavations  are 
supported  by  huge  frames  of  timber,  made 
by  adding  one  "  square  set  "  to  another  as 
required,  and  are  finally  filled  up  entirely 
with  rubbish. 

Another  method  of  working  a  wide  lode 
is  to  attack  it  in  slices  parallel  to  the  dip, 
removing  each  slice  separately,  as  if  it  were 
a  lode  of  ordinary  dimensions,  and  filling 
up  with  rubbish  (Fig.  381). 

We  have  here  been  supposing  that  the 

whole  of  the  lode  is  taken  away  from  wall  to  wall.  Other  cases 
may  arise.  Thus  at  Foxdale  mine,  in  the  Isle  of  Man,  we  have  to 
deal  with  a  vein  of  lead-bearing  rock  which  is  not  ore-bearing  for 
its  entire  width.  The  vein  runs  east  and  west,  and  in  places  is 
140  feet  wide.  Levels  are  driven  along  the  northern  and  southern 
boundaries,  and  show  whether  or  no  there  is  any  payable  ground 
on  these  walls ;  crosscuts  put  through  from  time  to  time  further 
prove  the  lode,  and  sometimes  there  may  be  three  parallel  workable 
portions  with  barren  rock  between  them.  Each  of  these  portions, 
which  will  rarely  exceed  1 2  feet  in  width,  is  then  treated  as  a 
separate  lode. 

The  rule  at  Foxdale  (Fig.  382)  is  to  drive  the  levels  15  fathoms 
apart,  and  to  effect  a  communication  between  two  adjacent  levels 
at  intervals  of  30  fathoms,  either  by  a  rise  or  a  winze.  The  lode 
thus  becomes  cut  up  into  blocks  1 5  fathoms  deep  by  30  fathoms 
long,  in  the  direction  of  the  strike.  These  blocks  are  worked 
away  from  below  upwards  in  separate  "pitches,"  each  10  fathoms 
long,  arranged  like  three  steps.  The  block  therefore  affords 


336 


ORE  AND  STONE-MINING. 


three  pitches,  or  subordinate  blocks.  Thus  if  ABDC  represents 
a  block  contained  between  an  upper  level  AB  and  a  level  CD, 
15  fathoms  below  it,  and  bounded  on  the  two  ends  by  the 
winzes  AC  and  BD,  we  must  first  divide  it  in  imagination  into 
the  three  parts  AEGC,  EFHG,  and  FBDH.  The  removal  of 
each  pitch,  or  third  of  a  block,  is  confided  to  a  separate  set  of 
men.  The  first  set  begin  at  the  bottom  of  AEGC,  and  take  off 
a  slice  6  feet  thick,  filling  up  the  vacant  space  with  rubbish ; 
then  they  begin  a  second  slice,  and  go  on  taking  off  slice  after 
slice  until  they  reach  the  level  above. 

Work  upon  the   second   division — viz.,  EFGH,  is  not  begun 
until  the  first  slice  of  the  adjacent  "pitch"  has  been  filled  up, 

FIG.  382. 


SCALE 

2    4-6    8    10   12   14.  16  18  20  22  FATHOMS 


05      10    15    20    25    30    35  4-0   4-5  METRES 

and  in  the  same  way  block  FBDH  is  not  attacked  until  at 
least  one  slice  of  EFHG  has  been  worked  away.  At -some  given 
time  the  workings  will  have  assumed  the  form  shown  in  the 
figure. 

If,  as  is  often  the  case,  there  is  a  hard  and  a  soft  part  in  the 
lode,  the  work  in  the  overhand  stopes  goes  on  as  follows  :  Start- 
ing from  a  winze,  the  miners  push  on  a  drivage  in  the  soft  part, 
and  timber  it  up  with  a  cap  resting  upon  the  hard  side  and 
upon  one  leg  (Fig.  383).  This  renders  the  working  of  the  hard 
part  very  much  less  expensive,  for  it  can  be  got  by  shots  which 
take  full  effect  in  such  large  openings.  Before  blasting  out  the 
side,  the  caps  are  supported  by  a  longitudinal  carrier  resting 
upon  a  few  upright  props  in  the  manner  shown  in  figure  384. 

All  the  rock  is  picked  in  the  mine,  and  any  waste  is  used  for 
filling  up.  At  last  the  whole  excavation  that  has  been  made 
is  packed,  with  the  exception  of  a  passage,  18  inches  high,  below 
the  caps,  along  which  the  men  can  creep  if  necessary.  A  floor 
of  planks  is  laid  down,  and  serves  to  make  a  bed  to  prevent  the 


FIG.  383. 


4  v  /. 


Scale,  o-f  Me&r&t 


FIG.  384. 


A.  Granite,  or  barren  part  of  the  lode  ;  B.  Soft  part  of  the  lode  ^ 
C.  Hard  part  of  the  lode  ;  D.  Leg ;  E.  Cap ;  F.  Floor  of  planks  ; 
G.  Longitudinal  cap  or  carrier ;  H.  Prop  ;  I.  Prop  ;  K.  Filling 
of  waste  rock. 


338  ORE  AND  STONE-MINING. 

loss  of  small  ore  when  the  next  stope  or  slice  is  taken  off.  Shoots 
or  "  passes  "  lined  with  timber  are  reserved  in  the  rubbish  ;  there 
is  generally  one  at  the  end  of  each  pitch  and  one  in  the  middle. 
In  this  way  the  miner  always  has  one  close  at  hand,  and  never 
need  wheel  the  ore  very  far.  The  shoots  are  furnished  with  doors 
at  the  bottom,  and  the  ore  is  drawn  off  directly  into  waggons 
underneath  without  any  shovelling. 

Care  is  taken  to  drive  a  crosscut  from  time  to  time,  to  prevent 
any  chance  of  possible  bunches  of  ore  in  the  sides  being  missed. 
Waste  rock  obtained  in  this  way  is  always  useful  for  filling  up. 
The  Foxdale  lode  furnishes  about  enough  barren  rock  to  fill  up 
the  excavation,  without  its  being  necessary  to  draw  supplies  from 
the  surface. 

The  timber  buried  in  the  rubbish  is  not  lost,  for  it  can  be 
withdrawn  when  the  next  slice  is  taken  off.  A  piece  of  J-inch 
iron  chain  is  made  fast  round  the  top  of  the  leg,  which  always 
has  the  small  end  at  the  bottom,  and  the  hook  of  a  special  lever 
is  put  into  a  suitable  link.  The  fulcrum  of  the  lever  is  carried 
by  an  upright  bar  attached  to  a  square  base,  and  by  applying 
pressure  to  the  lever  the  leg  is  gradually  pulled  up. 

Wide  Lodes  worked  with  Pillars  and  Chambers. — The  present 
method  of  working  the  wide  veins  at  the  Rio  Tinto  mines  may  be 
briefly  described  as  pillar  and  chamberwork,  with  a  solid  roof  and 
floor  between  the  working  horizons.  For  the  present  the  pillars 
must  be  looked  upon  as  permanent. 

The  details  of  the  system  are  as  follows  :  A  vertical  shaft  is 
sunk  in  the  adjacent  rock,  and  crosscuts  are  driven  out  to  the 
lode  at  intervals  of  25  metres  (82  feet);  these  form  the  main 
working  floors  or  horizons.  A  main  level  is  carried  along  the 
strike  of  the  lode  at  each  horizon,  and,  by  sinking  from  one  level 
and  rising  from  the  one  below,  a  vertical  intermediate  shaft  is 
formed,  effecting  a  communication  between  them.  All  this 
preliminary  work  is  done  by  the  aid  of  rock  drills.  An  inter- 
mediate level  is  next  pushed  out  along  the  strike  by  hand  labour 
midway  between  the  two  main  levels ;  the  vein  may  then  be 
regarded  in  imagination  as  divided  into  a  series  of  horizontal 
slices,  each  12  J  metres  in  thickness,  as  shown  by  the  dotted  lines, 
AB,  CD,  EF,  &c.  in  the  section  (Fig.  385).  The  formation  of 
pillars  now  begins :  the  lower  part  of  each  slice  is  cut  up  by  a 
network  of  drivages  3  to  3  J  metres  wide,  and  3  to  3  J  metres  high, 
at  right  angles  to  one  another,  leaving  pillars  6J  to  7  metres 
square  (Fig.  386).  A  very  large  amount  of  ore  is  produced 
in  this  way.  The  next  stage  in  the  process  of  mining  is 
heightening  and  widening  the  chambers ;  in  ordinary  hard 
pyrites  the  pillars  can  be  thinned  down  until  they  measure  only 
3  metres  by  3  metres,  and  the  chambers  can  be  carried  to  a 
height  of  9  to  i  o  metres.  Where  the  ground  is  weak  more  has 
to  be  left  for  support.  The  two  plans  (Figs.  386  and  387)  show  the 


EXPLOITATION. 


339 


initial  size  and  the  final  size  of  the  pillars,  whilst  the  section 
(Fig.  385)  further  explains  the  progress  of  the  work.  At  the  225- 
metres  horizon  there  are  preliminary  levels  3  metres  wide  and 
pillars  of  7  metres  ;  at  the  2i2j-metres  horizon  the  enlargement 
of  the  chambers  has  begun;  at  the  2oo-metres  level  the  process 
has  been  carried  further,  and  at  the  two  upper  horizons  it  has 
been  completed,  the  pillars  being  reduced  to  3  metres.  The  solid 
slice  of  ore,  2  J  to  3^  metres  thick  between  two  storeys,  remains  for 
the  present  untouched,  and  forms  with  the  small  pillars  a  reserve 
stock  which  can  be  removed  at  some  future  time.  Great  care  is 
taken  to  arrange  the  pillars  vertically  one  under  the  other  with 

FI0.386. 


FIG.  387. 


SCALE 


ME.TRE.SI 


their  centre  lines  coinciding  exactly.  When  operations  have 
been  finished,  the  workings  have  the  appearance  of  very  high 
columns  supporting  huge  arches.  It  must  not  be  supposed  that 
the  honeycombed  part  of  the  vein  formed  by  the  deserted  chambers 
is  entirely  unproductive;  a  very  large  surface  of  ore  is  left 
exposed  to  the  action  of  air  and  moisture,  oxidation  goes  on, 
copper  and  iron  sulphates  are  produced,  and  during  the  rainy 
season  water  trickling  down" the  sides  of  the  caverns  carries  them 
in  solution  to  the  bottom  of  the  mine.  The  coppery  water 
pumped  up  from  underground  is  led  into  precipitation  pits, 
similar  to  those  employed  for  treating  the  cupreous  solutions 
obtained  more  rapidly  from  the  ore  burnt  at  the  surface. 

At  the  present  time  the  quantity  of  ore  in  sight  is  so  great 
that  it  is  not  necessary  to  devise  schemes  for  removing  the 
reserves;  but  the  work  might  be  accomplished  by  a  filling-up 
process,  beginning  at  the  bottom.  The  pillars  and  the  intervening 


340 


ORE  AND  STONE-MINING. 


solid  floors  of  ore  could  be  removed  as  horizontal  slices,  fol- 
lowed by  a  filling  up  with  rubbish  let  down  from  the  surface. 
In  this  manner  the  workmen  would  always  be  standing  on  firm 
ground  within  easy  reach  of  the  ore. 

3.  MASSES. — The  methods  of  working  masses  may  be  classified 
thus: 

(a)  Method  by  chambers  without  filling  up. 

(6)  Method  by  horizontal  slices,  taken  in  descending  order,  allowing 

the  surface  to  sink  down, 
(c)  Method   by  horizontal   slices,  taken  in  ascending  order,  with 

complete  filling  up. 

(a)  The  first  of  the  three  methods  is  applicable  when  the  enclosing 
rock  is  strong  enough  to  allow  chambers  to  be  worked  out  without 

FIG.  388. 


SCALE 

J  0    2     4.     68     10  YARDS 

A.  "  Grey  limestone  " ;  B.  Limestone, the  so-called  "  Crease  measures  "; 

C.  Chambers   or  caverns   left  by  the  excavation  of  the  ore; 

D.  Brown  haematite  ;  E.  Top  or  Whitehead  limestone  ;  F.  Sand- 
stone (Millstone  Grit) ;   G,  Main  level ;    H.  Supporting  pillar 
built  up  of  stones  and  timber. 

danger  from  the  roof  and  sides  falling  in.  As  an  instance  I  may 
take  the  so-called  "  churns "  of  the  Forest  of  Dean,  which  are 
worked  for  iron  ore.  Brown  haematite  occurs  in  irregular  pockets 
in  a  certain  bed  of  the  Mountain  Limestone  (Fig.  388),  which  is  from 
14  to  1 6  yards  thick,  and  usually  dips  at  a  considerable  angle.  At 
the  particular  mine  chosen  as  an  example  the  dip  is  52°.  Perpen- 
dicular shafts  are  sunk,  and  the  ore-bearing  limestone  is  reached 
by  crosscuts  at  vertical  intervals  of  100  to  150  feet.  A  good  main 
level  is  driven  along  the  strike  of  this  bed,  and  small  crosscuts  are 
put  out  in  order  to  search  for  the  churns,  which  have  often  been 


EXPLOITATION.  34* 

followed  down  from  the  surface  to  a  depth  of  200  yards.  The 
exploitation  consists  in  removing  the  soft  ore  with  the  pick,  and 
supporting  the  roof  with  occasional  props  or  rough  walls  built  with 
pieces  of  ^barren  rock;  timber  and  stone  may  be  used  together^  as 
shown  in  the  figure.  If  the  pocket  is  very  steep  it  is  worked  like 
a  mineral  vein ;  the  men  stope  the  ore  away  overhand,  standing 
upon  platforms  of  timber  erected  across  the  chasm  left  by  workings 
below. 

(b)  An  excellent  example  of  the  second  method  of  working  is 
furnished  by  De  Beers  diamond  mine,  where  a  mass  of  diamond- 

FIG.  389. 


PLAN  OF  DE  BEERS  MINE. 

800     FT    LEVEL 


ORIENTAL  SHAFT 


"bearing  rock  occurs  as  a  huge  vertical  column,  with  an  irregular 
oval  section  (Figs.  30  and  31).  It  was  worked  for  many  years  as 
an  open  quarry,  but  falls  of  the  surrounding  rocks  (reef]  caused 
so  much  trouble,  as  the  huge  pit  increased  in  depth,  that  under- 
ground mining  had  to  be  adopted. 

The  system  consists  in  excavating  chambers,  and  then  letting 
rubbish  from  the  open  pit  above  run  in  and  fill  them  up.  The 
details  of  the  method  will  be  plain  from  consulting  Figs.  389,  390, 
and  391,  which  are  copied  from  the  second  and  third  annual 
reports  of  the  De  Beers  Company.  The  deposit  is  reached  by  an 
inclined  shaft  sunk  in  the  surrounding  rocks,  and  main  levels 
are  driven  at  successive  horizons  which  are  from  90  to  120  feet 
.apart  vertically.  Fig  389  shows  these  main  drivages  at_the  800- 


342 


ORE  AND  STONE-MINING. 


SCALES 


0      10    19    30  40 


60     70    80    M    100  FttT 


FIG.  391. 


FIG.  390.  feet  level;  there  are  two* 

principal  drivages  parallel 
to  each  other  and  follow- 
ing the  direction  of  the 
axis  of  the  rough  oval,  and 
from  them  cross  tunnels 
are  put  out  at  intervals 
of  36  feet,  and  extended 
to  the  limits  of  the  "  blue," 
or,  when  directed  to- 
wards each  other,  till 
they  meet.  Another  set 
of  levels  is  driven  at  a 
depth  of  30  feet  below 
the  main  tunnels,  and  a 
third  set  at  a  further 
depth  of  30  feet.  The 
block  of  ground  between 
two  main  horizons  thus 
becomes  divided  up  into  a 
series  of  horizontal  slices, 
30  feet  thick,  each  of 
which  is  cut  up  by  a  net- 
work of  tunnels  36  feet 
apart  extending  to  the 
surrounding  rock. 

When  this  rock  is 
reached,  the  tunnels  are 
widened  out  till  two  adja- 
cent working-places  meet 
as  shown  in  the  plan  (Fig.  390).  The  next  process  is  to  rise,  or  work 
upwards,  until  the  "blue"  is  traversed  and  the  waste  fallen  rock 

FIG.  392. 
Original    s 


A.  Enclosing  limestone  ;  B.  Eed  haematite  ;  C.  Sand  and  clay  ;, 
D.  Glacial  drift. 


EXPLOITATION. 


343 


above  it  is  met  with.  This  is  allowed  to  run  in  and  form  a 
upon  which  the  workmen  stand,  in  order  to  blast  down  the  re- 
maining part  of  the  slice  of  "  blue."  As  this  is  taken  away  the 
waste  rock  (reef]  follows.  Fig.  391  also  shows  that  the  workings 
in  an  upper  slice  are  always  further  advanced  than  those  in  a 
lower  one.  Only  the  main  levels  are  provided  with  regular 
tramways.  The  blue  got  in  the  intermediate  levels  is  thrown 

FIG.  393. 


Shaft 


Shaft 


Sand   &c. 


Jron  On 


down  shoots,  and  so  finds  its  way  to  the  main  level,  whence  it 
can  be  hoisted  to  the  surface. 

A  somewhat  similar  mode  of  working  is  customary  in  the  iron 
mines  of  North  Lancashire,  which  have  to  deal  with  irregular 
masses  of  hematite  in  the  Mountain  Limestone  (Fig.  392).* 

Shafts  are  sunk  at  a  distance  from  the  deposit,  which  is  reached 
by  crosscuts  at  intervals  of  10  fathoms  vertically.  Levels  and 
cross  levels  are  then  driven  which  bring  all  parts  within  easy 
reach  (Fig.  393).  Rises,  E,  R,  are  put  up  from  the  main  floor 

*  I  am  indebted  to  Mr.  J.  G.  Lawn,  A.K.S.M.  and  De  la  Beche 
Medallist,  for  his  notes  on  the  method  of  working ;  from  these,  and  from 
my  own  recollections,  this  description  has  been  written. 


344 


ORE  AND  STONE-MINING. 


or  horizon  to  the  next  one  above,  and  the  deposit  is  now  taken 
away  in  slices  or  "  heights,"  9  or  10  feet  thick.  A  and  B  of 
Fig.  394  represent  two  adjacent  rises.  The  men  starting  from 
-4,  push  out  the  drift  z,  and  those  from  E  the  drift  /,  until  they 
meet,  for  the  sake  of  ventilation.  This  air-road  il  has  to  be 
kept  open  while  work  is  proceeding  in  the  slice  or  height  in  this 
district.  Branch  drifts,  2  and  //,  are  carried  forward  to  the 
boundary  of  the  deposit  or  of  the  area  the  men  have  to  work,  and 
lastly  comes  the  robbing  of  the  ore  by  a  series  of  drifts,  such  as 
Si  4>  5i  6">  or  HI,  IV)  V,  in  the  order  of  the  numbers.  The 
work  is  thus  carried  on  towards  a  rise  and  not  from  it. 
After  the  ore  is  robbed,  the  roof  crushes  in,  smashing  the 
timber  and  forming  a  safe  ceiling  for  the  workings  in  the 

FIG.  394. 


next  slice  underneath.  The  surface  sinks  down  in  proportion  as 
the  ore  is  removed,  so  that  in  some  parts  of  the  district  immense 
holes  exist,  giving  evidence  of  the  working  out  of  vast  bodies  of 
haematite  underneath  (Fig.  392).  As  the  overlying  drift  often 
contains  clay,  rain  water  collects  in  these  holes,  and  it  has  to  be 
pumped  out  lest  it  should  break  through  and  drown  the  miners. 

The  rises  are  usually  made  6  feet  by  4  feet  6  inches  within  the 
timbering,  which  consists  of  sets  of  Norway  or  Swedish  timber 
6  or  7  inches  square,  simply  halved  at  the  joints  and  placed 
directly  one  above  the  other.  Most  of  the  rises  are  divided  into 
two  compartments  by  pieces  of  3 -inch  plank  cut  to  the  right 
length  and  wedged  in;  these  are  made  firm  by  nailing  on  to 
the  rise-timber  "listing  pieces,"  strips  of  wood  3  inches  by  J 
inch,  on  each  side.  One  of  the  compartments  serves  for  a  ladder- 
way,  for  pulling  up  timber  and  for  an  airway ;  the  other  as  a 
receptacle  for  the  ore.  The  latter  is  called  a  "hurry,"  and  is 
provided  at  the  bottom  with  an  inclined  shoot  through  which  the 
ore  can  be  let  into  waggons  or  "  bogies  "  at  pleasure.  Sometimes 


EXPLOITATION, 


345 


the  rise  is  made  9  feet  by  4  feet  6  inches,  and  divided  into  three 
compartments — viz.,  two  hurries,  and  a  ladderway  between  them. 
One  hurry  then  serves  for  ore,  and  the  other  for  rubbish. 

When  the  men  have  all  but  removed  one  slice  or  "height,"  they 
take  out  the  timber  of  the  rise  on  one  side,  in  order  to  start  a  new 
drift ;  it  is  about  7  feet  wide,  and  is  supported  by  frames,  each 
made  of  a  cap  or  head -tree  resting  upon  two  legs  or  "  forks."  To 
protect  the  men  while  working  in  the  forebreast,  small  planks 
(spiles)  are  driven  under  one  head-tree  and  over  the  next,  and, 
if  necessary,  along  the  sides  behind  the  props.  The  men  are  not 
allowed  to  advance  more  than  4  feet  beyond  their  timber.  As 
soon  as  the  slice  above  is  quite  exhausted,  they  open  out  at  the 
other  side  of  their  rise,  and  after  putting  in  a  strong  covering  of 

FIG.  395. 


timber,  they  clear  all  the  rise  of  its  lining  down  to  the  level  at 
which  they  are  working.  In  driving  below  the  old  timber  and 
rubbish,  it  is  necessary  to  be  careful  that  the  supporting  frames 
are  properly  put  in  and  kept  well  forward ;  they  are  often  held  in 
place  by  nailing  spiles  to  them,  but  this  is  only  necessary  before 
they  get  the  weight  from  above.  It  is  possible  in  many  cases  to 
save  much  of  the  timber  used  in  lining  the  drifts  which  are  made 
for  robbing  the  ore,  but  in  all  cases  the  roof  comes  down  very 
quickly,  whether  the  timber  is  left  in  or  not. 

(c)  The  last  method — namely,  working  away  the  mass  by  hori- 
zontal slices,  in  ascending  order,  with  complete  filling  up — 
exactly  resembles  that  which  is  adopted  for  certain  wide  veins, 
such  as  the  lode  at  the  Van  mine,  Montgomeryshire.  However, 
it  may  be  well  to  mention,  as  an  example,  the  great  zinc  ore 
stockwork  at  Diepenlinchen,  near  Stolberg.  The  Mountain 
Limestone  is  full  of  cracks  and  cavities  containing  blende,  which 
cannot  be  worked  to  advantage  without  breaking  down  the  whole 


346 


ORE  AND  STONE-MINING. 


of  the  rock.  The  limestone  is  ore-bearing  over  an  oval  area, 
120  metres  long  from  east  to  west  and  50  from  north  to  south 
(130  yards  by  54  yards). 

This  great  mass  of  zinc-bearing  rock  is  subdivided  for  the  pur- 
pose of  working  into  a  series  of  storeys  or  floors,  each  16  metres. 
(52^  feet)  thick  vertically,  and  a  main  level  is  driven  along  the 
major  axis  of  the  oval  at  the  bottom  of  each  storey,  as  shown  in 
Fig.  396.  Cross-cuts,  14  metres  apart,  are  driven  out  north  and 
south  from  each  main  level,  and  are  connected  with  similar  cross- 
cuts below  by  winzes.  The  block  of  ground  between  two  main 
levels  is  then  taken  away  in  slices,  2  metres  thick,  in  ascending 
order.  However,  with  the  view  of  saving  the  expense  of  putting 

FIG.  396. 


2OO METRES  LLVCL 


^ 2/6  METRES  LEVEL 

^%%^^ 

in  timber  to  support  the  deads,  which  would  be  necessary  if  the 
main  roads  had  to  be  kept  up  in  a  part  of  the  mine  stowed  with 
rubbish,  the  first  two  slices — that  is  to  say,  the  one  in  which  the 
levels  are  driven  and  the  one  immediately  above  it — are  left  intact 
at  the  outset.  Work  is  started  from  a  winze  at  a  point  2  metres 
above  the  top  of  the  level,  and  the  whole  area  of  the  deposit  cleared 
out  for  a  height  of  2  metres  ;  the  excavation  is  then  filled  up  with 
deads.  The  deads  are  obtained  by  picking  the  rock  broken  down 
in  the  stopes,  or  from  any  drivings  or  sinkings  in  barren  ground, 
and  also  by  sending  down  supplies  from  the  surface.  Shoots  are 
reserved  in  the  stowing  for  throwing  down  the  ore,  which  is 
drawn  off  at  the  bottom  when  required. 

Fig.  396  shows  the  stoping  going  on  between  the  200  and  the 
2i6-metres  levels.  When  the  stopes  come  up  to  the  sole  of  the 
2oo-metres  level,  the  ore  surrounding  the  network  of  levels  and 
that  of  the  overlying  slice  can  be  attacked.  By  this  time  this 
double  slice,  4  metres  thick,  is  somewhat  crushed  and  broken. 


EXPLOITATION.  347 

It  would  be  dangerous  to  have  the  wide  working-places,  which 
can  be  excavated  without  fear  in  virgin  ground;  therefore, 
just  as  happened  in  the  Van  Mine,  the  two  last  slices  are 
got  by  a  series  of  small  drivings,  in  which  the  miners  resort  to 
a  process  of  spilling.  By  applying  this  process  the  remainder 
of  the  ore  is  obtained  in  safety,  and  the  final  result  is  that  the 
great  mass  of  zinc-bearing  rock  is  replaced  by  barren  material 
with  the  expenditure  of  very  little  money  for  timber. 


(     348     ) 


CHAPTER  VII. 
HAULAGE  OE  TKANSPOBT. 

Underground  transport — Shoots — Pipes — Carriage  by  persons — Sledges — 
Wheeled  vehicles — Mechanical  haulage — Boats — Transport  above 
ground  by  similar  means  and  by  aerial  ropeways. 

AFTER  having  been  excavated,  the  mineral  must  be  conveyed 
to  the  surface.  In  very  many  cases  the  journey  is  performed  in 
two  stages — first,  along  a  more  or  less  horizontal  road  to  the  shaft- 
bottom  ;  and  thence  by  a  vertical  or  inclined  road  which  leads  up 
to  the  daylight.  The  first  process  is  often  spoken  of  as  haulage 
and  the  second  as  winding :  but  there  is  no  distinct  line  of  de- 
marcation between  the  two,  for  certain  sloping  passages,  called 
shafts  by  the  ore-miner,  would  be  denied  that  name  by  the  collier. 
It  will  be  convenient  to  say  a  few  words  here  about  transport 
above  ground,  although,  strictly  speaking,  this  subject  should  not 
be  dealt  with  until  after  the  chapter  on  winding. 

The  transit  of  the  mineral  from  the  working-place  to  the 
shaft  may  be  carried  on  in  part  or  wholly  by  one  of  the  following 
processes : 

I.  Fall  down  a  shoot  (mill  or  pass}. 
II.  Flow  along  pipes  or  troughs  (launders). 

III.  Carriage  by  persons. 

IV.  Conveyance  by  sledges. 

V.  ,,  ,,    vehicles  with  wheels. 

VI.  „  „   boats. 

I.  TALL  DOWN  A  SHOOT.— This  first  method  is  one  to 
which  reference  has  already  been  made  more  than  once  in 
describing  the  modes  of  working.  When  a  deposit  is  inclined  at 
a  steep  angle,  or  when  a  mass  has  to  be  dealt  with,  the  mineral 
will  readily  drop  from  the  working-place  to  the  level  below.  The 
passages  provided  for  this  purpose  are  called  "  shoots,"  "  passes," 
or  "  mills." 

If  the  excavation  is  filled  up  with  rubbish,  a  space  like  a  small 
shaft  is  reserved  in  the  stowing  by  building  a  wall  with  some 
of  the  large  stones.  This  kind  of  "pass"  may  be  described  as 
a  large  chimney,  about  3  feet  in  diameter,  lined  with  coarse 
rubble  masonry.  To  prevent  choking,  it  is  advisable  to  make 
the  pass  slightly  conical,  the  large  end  at  the  bottom.  It  may 


HAULAGE  OR  TRANSPORT.  349 

be  constructed  in  the  middle  of  the  rubbish,  or  if  there  is  a 
convenient  smooth  face  on  the  footwall  of  a  lode,  a  semicircular 
wall  built  against  it  encloses  a  space  very  suitable  for  the  purpose 
required.  The  pass  may  serve  also  as  a  climbing  way  for  the 
men,  especially  if  it  is  provided  with  a  chain ;  but  it  should  be 
used  in  this  manner  only  for  short  distances.  It  is  far  better  to 
keep  the  ore-pass  distinct  from  the  climbing  way,  in  case  any 
stones  should  lodge  on  the  sides  and  fall  during  the  ascent  or 
descent  of  the  men. 

A  pass  is  often  lined  with  timber  instead  of  stone,  and  some- 
times it  is  merely  an  intermediate  shaft  or  winze  set  apart  as  a 
shoot.  At  the  Van  Mine  the  passes,  whether  they  are  small 
shafts  sunk  on  purpose,  or  passages  reserved  in  the  rubbish 
used  as  filling,  are  6  feet  by  3  feet,  within  the  timber ; 
each  pass  is  divided  into  two  unequal  compartments  by  a 
partition  made  of  ij-inch  plank  nailed  to  cross-timbers 
called  dividings,  and  the  larger  one  is  closely  lined  with  similar 
planks.  This  forms  the  "  shoot "  proper.  The  small  compart- 
ment is  provided  with  ladders  and  serves  as  a  climbing  way,  and 
is  also  useful  in  case  the  larger  one  should  become  choked ; 
a  board  can  be  taken  out  from  the  side  at  any  time,  and  large 
stones  obstructing  the  passage  can  be  dislodged  with  safety. 
Vertical  passes  lined  with  timber  sometimes  have  pieces  of  steel 
rail  put  across  at  intervals,  to  break  the  fall  of  the  "  stuff." 

The  pass  is  provided  at  the  bottom  with  a  mouth  closed  by  a 
door  of  some  kind,  and  when  this  is  opened,  the  mineral  falls  out 
into  the  waggon  which  has  been  brought  underneath, 

II.  FLOW  ALONG   PIPES.  — This   method   of  transport 
becomes  available  when  one  has  to  deal  with  liquid  or  gaseous 
minerals,  or  with  solutions,  but  these  cases  occur  more  frequently 
above  than  below  ground.     However,  brine  is  led  along  wooden 
launders  and  pipes  in  some  salt  mines.     Natural  inflammable  gas 
in  a  few  exceptional  cases  is  piped  off  from  a  blower  and  burnt 
for  illuminating  purposes ;  this  is  done  at  a  salt  mine  at  Bex  in 
Switzerland. 

III.  CARRIAGE    BY  PERSONS.— The   simplest  and  no 
doubt  the  oldest  method  of  transport  along  underground  roads  is 
carriage  by  persons.     It  still  survives  in  some  places  for  short 
distances. 

In  the  Forest  of  Dean,  boys  carry  iron  ore  on  the  back  in  oval 
trays,  called  "billies,"  from  the  actual  working-place  to  the 
nearest  barrow-road  or  waggon-road.  The  tray  is  made  of  wood, 
with  a  rim  of  sheet  iron,  and  is  about  6  inches  deep,  22  inches 
in  length  in  the  direction  of  the  long  axis,  and  12  to  15  in  the 
direction  of  the  short  one.  The  load  carried  in  a  "  billy  "  varies, 
according  to  the  nature  of  the  ore  and  the  strength  of  the  lad, 
from  90  to  112  Ibs.  or  even  more.  The  lad  goes  on  all-fours, 
using  his  hands  to  support  himself  as  he  makes  his  way  through 


350  OKE  AND  STONE-MINING. 

low  and  tortuous  passages.  This  method  of  transport  is  rendered 
necessary  by  the  nature  of  the  excavations,  which  are  very  irreg- 
ular ;  but  the  distances  along  which  the  ore  is  carried  are  small, 
generally  from  30  or  40  to  50  yards,  and  rarely  as  much  as 
100  yards. 

The  German  miner  commonly  makes  use  of  a  tray  into  which 
he  scrapes  his  mineral  or  rubbish  with  a  tool  like  a  hoe,  and  he 
then  carries  his  load  to  the  nearest  "  pass  "  or  to  a  waggon-road 
in  the  immediate  neighbourhood. 

In  the  little  slate  mines  near  Cochem  on  the  Moselle,  men  and 
lads  carry  up  the  blocks  of  slate  upon  their  backs,  walking  upon 
steps  cut  in  the  rock.  They  come  up  with  their  hands  upon 
the  ground,  bent  almost  double  under  the  weight  of  the  block, 
which  rests  upon  a  thick  pad.  Again,  blocks  of  slate  are  still 
carried  on  the  back  from  the  working-place  to  the  waggon-roads 
in  the  slate  mines  of  the  Ardennes.  In  the  Sicilian  sulphur 
mines  the  same  method  is  common,  and  it  is  also  found  in 
some  parts  of  Spain  and  China,  where  baskets  are  used,  whilst 
bags  are  employed  in  Mexico  and  Japan.  Indeed,  in  these  cases, 
as  at  Cochem,  the  mineral  is  not  only  carried  along  comparatively 
level  roads  but  is  also  brought  to  the  surface. 

IV.  CONVEYANCE   BY   SLEDGES.— Sledges,   or   sleds, 
enable  greater  loads  to  be  transported ;  but  they  are  not  available 
unless  the  conveyance  takes  place  along  roads  sloping  downwards. 
They  are  little  employed  underground. 

V.  CONVEYANCE  BY  VEHICLES  WITH  WHEELS.— 
We  now  come  to  the  methods  by  which  minerals  and  rubbish  are 
usually  transported  both  above  and  below  ground — viz.,  by  some 
kind  of  wheeled  vehicle.     Here  we  may  at  once  make  two  classes. 
A.  Vehicles  running  upon  the  ground  or  on  boards ;  B.   vehicles 
running  upon  rails. 

A.  Vehicles  Running  on  the  Ground  or  on  Boards. — 
Wheelbarrow :  The  simplest  wheeled  carriage  is  the  barrow. 
It  consists  of  a  body  with  two  handles  and  one  wheel.  The 
barrow  used  in  Cornwall  at  the  present  day  is  not  unlike  that 
figured  more  than  three  centuries  ago  by  Agricola.  It  has 
no  legs,  but  in  many  ore-mines  a  barrow  with  legs  is  em- 
ployed, somewhat  resembling  a  navvy's  barrow.  Mine-barrows 
are  usually  made  of  wood,  and  have  either  a  wooden  or  a  steel 
wheel.  The  Cornish  barrow  is  tipped  sideways,  whilst  the  barrow 
with  legs  is  tipped  either  sideways  or  over  the  end.  This  latter 
form  of  barrow  requires  a  higher  and  better  level ;  it  is  a  more 
advantageous  appliance,  as  it  throws  a  greater  part  of  the  load  on 
to  the  wheel  and  relieves  the  miner's  arms  to  a  certain  extent. 
The  barrow  often  runs  along  the  natural  floor  of  the  working- 
place  or  level,  but  less  labour  is  required  if  it  is  provided  with  a 
road  made  of  planks  or  strips  of  iron. 

Carts  and  Waggons. — In  the  low  passages,  only  18  inches  to 


HAULAGE  OR  TRANSPORT.  351 

20  inches  high  (Fahrten),  leading  from  the  working  face  of  the 
copper-shale  mines  at  Mansfeld  to  the  main  roads,  tiny  waggons 
on  four  wheels  are  employed. 

Carts  drawn  by  horses  are  used  in  some  large  underground 
quarries. 

A  mine  waggon  largely  employed  in  Germany  at  one  time,  and 
still  seen  occasionally,  is  the  so-called  Hungarian  "  Hund."  It 
has  a  rectangular  body  resting  upon  four  wheels,  two  small  in 
front  and  two  large  near  the  middle ;  the  workman  presses  down  a 
little  handle  at  the  back  to  make  the  load  rest  upon  the  two  big 
wheels  only,  and  pushes  the  waggon  along  a  board  at  the  bottom 
of  the  level.  The  Germans  have  also  used  four-wheeled  waggons 
running  upon  two  boards  ;  and  they  were  sometimes  provided  with 
a  projecting  pin  underneath  which  kept  them  upon  the  track. 

B.  Vehicles  Running  upon  Rails. — The  points  to  be  con- 
siderd  are  (a)  the  road  ;  (b)  the  waggons  ;  (c)  the  power  employed 
for  traction. 

(a)  Railways. — Cast-iron  tram-plates  were  introduced  in  the 
last  century,  and  were  succeeded  by  wrought-iron  rails  ;  these  in 
their  turn  are  being  superseded  by  rails  made  of  steel.  Various 
forms  of  rails  are  in  use.  The  simplest  is  a  bar  of  iron  set  on 
its  edge,  or  a  strip  of  flat  iron  nailed  to  longitudinal  sleepers. 
Rails  of  the  former  kind  are  made,  for  instance,  of  bars  J  by^  2 \ 
inches,  or  f  by  2j  inches,  fixed  by  wooden  wedges  in  slits  cut  in 
the  sleepers.  This  rail  has  the  disadvantage  of  wearing  a  groove 
in  the  flange  of  the  wheel,  but  it  is  easily  and  quickly  laid  and 
readily  bent  into  curves.  Rails  made  of  bars  of  round  iron  are 
used  in  some  Welsh  slate  quarries. 

The  bridge-rail  was  in  great  favour  at  one  time,  either  laid 
upon  longitudinal  or  cross  sleepers ;  but  nowadays  flanged 
T-headed  rails  made  of  steel  are  preferred.  Care  should  be 
taken  to  have  strong  and  well-laid  lines,  especially  where  there  is 
likely  to  be  much  traffic.  In  this,  as  in  many  other  depart- 
ments of  mining,  it  is  very  bad 

economy  to  cut  down  the  ori-  FlG-  397-  FIG.  398. 

ginal  expenses  too  much.  What 
is  saved  on  the  first  cost  will  be 
spent  over  and  over  again  in 
repairs,  to  say  nothing  of  the 
loss  of  time  and  money  caused 
by  delays  in  the  traffic. 

The  gauge  varies  from  14 
inches  to  3  feet  or  more ;  20 
inches  to  22  inches  is  a  common 
gauge  in  vein  mining.  The 
weight  of  the  rails  for  such  roads  is  from  10  to  30  Ibs.  per  yard. 
Fig8-  397  and  398  show  the  sections  adopted  respectively  by 
Legrand  of  Mons  and  Howard  of  Bedford,  for  rails  weighing 


352 


ORE  AND  STONE-MINING. 


1 8  Ibs.  per  yard.  The  rails  may  be  simply  spiked  to  wooden 
sleepers,  or  they  may  be  laid  in  chairs.  In  important  roads  fish- 
plates should  be  used. 

There  is  a  tendency  at  the  present  day  to  adopt  steel  sleepers, 
which  are  supplied  by  the  makers  to  suit  roads  of  various  gauges. 
They  have  proved  to  be  very  convenient  and  efficient,  and  in 
this  country  they  are  cheaper  in  the  end  than  wood.  Among 
their  advantages  are  exact  uniformity  of  gauge,  easy  and  rapid 

FIG.  399. 


laying,  fewer  repairs.     They  are  usually  made  of  rolled  steel,  and 
the  rails  are  fixed  either  by  clips,  or  by  clips  and  keys. 

One  form  of  road  supplied  by  Legrand  of  Mons  (Fig.  399),  has 
the  clips  of  one  sleeper  on  the  outside  of  the  rail  and  those  of  the 
next  on  the  inside  of  the  rail.  The  clips  are  firmly  riveted  to 
the  sleepers.  In  constructing  the  road,  the  sleepers  B  are  laid 
at  suitable  distances  apart,  exactly  parallel  to  one  another ;  the 
alternate  sleepers  A  are  then  put  in  obliquely,  as  shown  by  the 
dotted  lines,  and  knocked  into  position  with  a  hammer ;  the 
rails  are  joined  by  fish-plates. 

Howard's  sleeper  (Fig.  400)  is  made  from  a  plate  of  steel  rolled 
with  a  corrugation ;  the  lips  which  constitute  the  chairs  for  the 

rails  are  formed  by  pressing 

FIG.  400.  down  this  corrugation  with- 

out cutting  away  any  of  the 
metal .  The  jointing  sleepers 
have  a  double  corrugation, 

and  the  rails    are   fastened 

with    a    simple   key   which 

is  serrated  on  one  side.     Some  of  Howard's  sleepers  for  under- 
ground work  can  be  used  without  any  keys. 

Bagnall's  sleeper  is  also  distinguished  by  longitudinal  corru- 
gations which  stiffen  it  and  prevent  its  buckling.  The  Widnes 
Chair  and  Sleeper  Company  prefer  a  section  like  that  of  a  V-shaped 
trough ;  they  claim  that  the  penetration  of  this  sleeper  into  the 
ground  ensures  great  stability. 

Where  a  mine  has  a  stock  of  old  rails  or  old  iron,  it  is  often 
more  economical  to  convert  it  into  sleepers  than  to  sell  it  as  scrap. 


HAULAGE  OR  TRANSPORT. 


353 


There  are  several  methods  in  use.  White  *  of  Widnes  utilises  old 
bridge  rails  (Figs.  401  and  401  a)  by  inserting  two  clips  (Figs.  402 
and  40  2  a)  into  a  piece  of  rail  cut  to  the  required  length  ;  the 
clip  is  held  in  place  by  a  pin  which  passes  into  a  hole  punched 


FIG.  401. 


FIG.  40 1  a. 


FIG.  402. 


FIG.  4020. 


in  the  sleeper.  At  the  Llechwedd  slate  mine  in  North  Wales, 
two  other  methods  have  been  devised  by  Mr.  0.  Warren  Roberts 
(Figs.  403  and  404)  for  utilising  old  channel  iron  and  flat  iron. 
Stamped  iron  clips  are  riveted  on  so  as  to  take  the  outer  side  of 


FIG.  403. 


_^=>7=aA&<&, 


mis* 


FIG.  404. 


the  flange  of  the  rail,  and  similar  clips  are  bolted  on  against  the 
inner  flange.  In  order  to  allow  for  any  small  irregularity  in  the 
width  of  the  flange,  the  hole  for  the  bolt  is  made  oval,  and  this 
enables  the  clip  to  be  adjusted  to  the  flange  exactly. 

*  Engineering,  vol.  lv.,  1893,  P-  H6- 

z 


354 


ORE  AND  STONE-MINING. 


Points  and  crossings  must  be  provided.  The  points  may  be 
like  those  of  an  ordinary  railway,  with  tongues  moved  by  levers. 
Another  plan  is  to  leave  gaps  between  the  rails  where  the  lines 
diverge  or  cross,,  and  interpose  plates  of  cast-iron  upon  which  the 
flanges  of  the  wheels  run  without  any  difficulty.  This  arrange- 
ment is  suitable  for  cases  where  a  man  is  pushing  the  waggon,  for 
he  can  turn  it  on  to  whichever  road  he  chooses,  but  it  will  not 
answer  in  the  case  of  haulage  by  engine  power.  Each  plate  has  a 
rim  or  edge  on  the  outer  side,  which  prevents  the  wheels  from 
running  off. 

Flat  plates  are  commonly  used  where  there  is  a  very  sharp 
bend  in  the  road,  such  as  when  a  cross-cut  joins  a  level  almost,  if 
not  quite,  at  right  angles.  The  plate  is  made  of  cast-iron  with 
ridges  forming  prolongations  of  the  rails  as  shown  in  Fig.  405. 


FIG.  405. 


FIG.  406. 


The  waggon  leaves  the  metals  and  the  flanges  of  the  wheels  run 
upon  the  plate ;  as  its  surface  is  perfectly  smooth,  the  waggon 
is  easily  turned  into  the  required  direction,  and  the  curved 
ridges  guide  the  wheels  into  the  track  which  they  have  to 
follow. 

In  places  where  there  is  a  difficulty  in  procuring  a  casting, 
the  plate  may  be  made  of  sheet  iron,  and  the  necessary 
guiding  ridges  are  formed  by  the  overlapping  ends  of  the  rails. 
The  flange  of  the  rail  is  cut  away  for  a  length  of  8  or  9 
inches  and  also  part  of  the  web ;  the  projecting  piece  of  the  head 
is  then  hammered  out  so  that  the  top  of  the  rail  slopes  down 
sufficiently  to  touch  the  plate. 

Another  device  for  guiding  a  waggon  from  a  plate  on  to  a 
line  of  rails  is  a  curved  piece  of  round  iron,  i  inch  in  diameter 
(Fig.  406).  The  two  ends  are  bent  at  right  angles  and  sharpened 
so  that  they  can  be  driven  into  a  sleeper  at  the  edge  of  the  flat 
plate.  The  ridge  formed  by  this  piece  of  iron,  guides  the  inner 
side  of  tho  flange  of  the  wheel. 


HAULAGE  OR  TRANSPORT.  355 

The  inclination  of  the  road  is  not  without  importance,  because 
there  are  usually  waggons  travelling  in  both  directions,  full  ones 
going  towards  the  shaft  or  other  outlet  from  the  mine,  and  empty 
ones  returning  to  the  working-places.  The  inclination  down- 
wards towards  the  shaft  assists  the  work,  but  if  it  is  too  great  the 
return  journey  causes  a  useless  expenditure  of  labour. 

The  rule  in  many  ore-mines  is  to  drive  the  levels  as  flat  as 
possible,  with  only  just  slope  enough  to  make  the  water  flow 
away;  the  tendency  of  the  workmen  is  always  to  rise  too  much, 
and  one  sometimes  meets  with  old  levels  where,  through  careless- 
ness or  inattention  of  the  agent,  the  loss  of  level  is  very  consider- 
able. An  inclination  of  -£  to  J  inch  per  yard,  or  i  in  216  to  i  in 
288  is  common. 

The  condition  of  the  road  between  the  metals  deserves  more 
attention  than  is  usually  bestowed  upon  it.  There  is  unneces- 
sary labour  on  the  part  of  the  man  or  the  horse  employed  in 
traction,  if  the  road  upon  which  he  walks  presents  obstacles 
through  great  unevenness.  I  have  seen  roads  which  were  simply 
a  succession  of  deep  puddles  between  the  sleepers,  a  striking  con- 
trast to  the  well-kept  main  levels  at  the  Mansfeld  copper  mines. 
These  levels  are  carefully  paved  with  artificial  stones,  made  from 
slag  afc  the  Company's  smelting  works.  The  paving-stones  are 
about  5  inches  square  at  the  top  and  6  inches  deep  ;  they  are 
also  sold  to  the  public,  at  prices  varying  from  fc£.  to  id.  each. 

(b)  Waggons. — Mine -waggons  are  made  of  wood,  iron  or  steel. 
They  consist  of  a  body  or  box  resting  on  a  frame  carried  by  four 
wheels.     They  vary  greatly  in  shape  and  size  according  to  the 
nature  of  the  excavation  and  the  kind 
of  material  transported.  FIG.  407. 

Figure  407  represents  the  plain  but 
strong  waggon  of  the  Van  Mine, 
Montgomeryshire,  with  a  rectangular 
body  of  sheet  iron,  an  oak  frame  and 
cast  steel  wheels.  The  top  is  strength- 
ened by  a  band  of  flat  iron.  The 
wheels  are  n  finches  in  diameter  and 
are  just  low  enough  to  go  under  the  body ;  they  are  therefore 
protected  from  blows,  to  which  they  would  otherwise  be  liable 
from  stones  dropping  during  the  process  of  filling.  The  waggon 
is  emptied  by  being  run  in  to  a  "  tippler,"  that  is  to  say,  a  cage 
turning  on  pivots,  which  enables  it  to  be  completely  overturned. 

At  the  Mansfeld  copper  mines  the  general  shape  is  similar. 
Formerly  waggons  of  various  shapes  and  sizes  were  in  use,  but 
now  one  uniform  model  has  been  adopted.  The  body  is  made  of 
sheet-iron  l  inch  thick,  and  the  upper  edge  is  strengthened  by  an 
iron  band  |~|  inch  thick  and  2j  inches  wide,  whilst  the  corners 
are  stiffened  with  angle  iron.  The  body  is  3  feet  5^  inches  long, 
2  feet  2  inches  broad,  and  i  foot  lof  inches  deep  inside.  The 


356 


ORE  AND  STONE-MINING. 


capacity  of  the  waggon  is  13^  cubic  feet,  and  it  carries  10  cwt. 
The  body  rests  upon  two  pieces  of  iron  placed  lengthwise, 
across  which  are  fixed  the  two  axles.  The  wheels  are  of  chilled 
cast-iron  with  special  grease-boxes.  The  gauge  of  the  road  is 
19 J  inches,  and  the  wheels  are  nj  inches  in  diameter,  so  that 
they  can  be  placed  under  the  waggon.  The  total  height  of  the 
waggon  is  3  feet  i  inch,  and  it  weighs  716  Ibs. 

When  made  of  sheet-iron  or  steel  the  sides  can  be  bent,  as 
shown  in  Figs.  408  and  409,  and  larger  wheels  can  be  employed 
without  unduly  raising  the  body. 

In  order  to  suit  the  small  levels  of  some  vein  mines,  the  waggons 
are  made  long  and  narrow.  In  the  Isle  of  Man,  one  meets  with 
waggons  6  feet  long  and  only  19  to  21  inches  wide  at  the  top  ; 
the  depth  being  2  feet.  The  sides  slope  inwards  so  that  the  bottom 
is  only  13  inches  wide  by  4  feet  9  inches,  or  5  feet  long.  The 
waggons  are  made  of  sheet  steel  about  y\  inch  thick,  or  of  i|  inch 


FIG.  408. 


FIG.  409. 


plank.  The  discharge  is  by  a  door  at  one  end,  kept  in  its  place 
by  a  bolt.  When  the  waggon  has  to  be  emptied,  the  miner 
knocks  up  this  bolt  and  lifts  the  waggon  up  behind  till  it  slopes 
enough  for  the  "  stuff  "  to  run  out.  The  top  of  the  steel  waggons 
is  stiffened  by  a  band  of  J-inch  iron  2  inches  wide  firmly  riveted 
on,  and  pieces  of  angle- iron,  where  the  plates  come  together,  give 
a  further  amount  of  strength.  Wooden  waggons  have  the 
bottom  lined  with  sheet-iron  ^  inch  thick. 

The  diameter  and  nature  of  the  wheels  vary.  At  one  mine 
in  the  Isle  of  Man  the  wheels  are  loj  inches  in  diameter,  and  run 
loose  upon  the  axles,  which  are  bolted  to  the  frame  under  the  body  ; 
they  are  1 5  inches  apart,  from  centre  to  centre.  The  wheels  are 
brought  close  together  with  a  view  of  making  the  waggons  pass 
round  curves  without  trouble.  In  order  to  render  the  tipping 
easy,  the  centre  of  the  front  axle  is  placed  6  inches  in  front  of  the 
middle  of  the  waggon ;  the  miner,  therefore,  has  the  greater  part 
of  his  load  balanced  when  he  pivots  his  waggon  on  the  axle  of  the 
front  wheels  in  the  act  of  discharging  it. 

At  a  neighbouring  mine  under  very  similar  conditions  cast- 
iron  brackets  are  bolted  under  the  body  to  receive  the  two  axles 
to  which  the  wheels  are  firmly  keyed,  but  the  hinder  axle  is  not 


HAULAGE  OR  TRANSPORT.  357 

in  any  way  attached  to  the  bracket ;  when  it  is  desired  to  empty 
the  waggon,  the  hind  end  is  lifted  up  and  both  sets  of  wheels 
remain  on  the  ground.  The  hind  axle  is  made  fast  to  the  front 
one  by  a  couple  of  straps,  for  otherwise  the  hind  wheels  might  run 
away  when  the  waggon  was  emptied.  A  disadvantage  of  this  kind 
of  waggon  is  that  it  may  require  two  men  to  replace  it  on  the 
road  if  it  comes  off;  one  may  be  wanted  to  see  that  the  wheels 
will  drop  properly  on  to  the  rails,  while  the  other  is  managing 
the  body. 

In  both  these  waggons  the  wheels  project  outside  the  body, 
instead  of  being  underneath  it  out  of  harm's  way,  but  they  are 
protected  to  a  certain  extent  by  the  overhanging  sides,  and  they 
can  be  further  screened  by  riveting  on  little  shields  of  sheet-iron. 
The  lateral  position  of  the  wheels  reduces  the  height  of  the  waggon 
required  for  any  given  capacity,  a  decided  advantage  when  it  has 
to  be  filled  with  the  shovel ;  but  in  ordinary  vein  mining  the  ore 
ought  to  be  drawn  down  from  shoots,  and  therefore  the  benefit  of 
easier  shovelling  comes  into  play  only  when  loading  rubbish  or  ore 
in  such  places  as  the  "  ends." 

In  some  mines  the  mineral  is  loaded  in  the  level  into  an  iron 
bucket  (kibble)  standing  upon  a  trolley,  which  is  merely  a  small 
platform  upon  four  wheels.  This  trolley  is  pushed  (trammed)  to 
the  shaft ;  the  full  kibble  is  hooked  on  to  the  winding  rope  and 
drawn  up,  whilst  an  empty  kibble  is  placed  upon  the  trolley  and 
trammed  along  the  level  to  the  spot  where  it  is  again  loaded  from 
a  shoot  or  by  the  shovel. 

Wheels  for  mine-waggons  generally  have  a  single  flange,  and 
are  made  of  ordinary  cast-iron,  chilled  cast-iron,  cast-steel,  or 
forged  steel.  Steel  and  chilled  cast-iron  are  the  materials  most 
in  favour;  both  have  advantages.  The  wheels  made  of  chilled 
cast-iron  are  rather  heavier  than  those  of  steel,  and  are  brittle ; 
the  flange,  for  instance,  will  break  under  a  blow  which  will  not 
damage  a  steel  wheel;  but  a  pair  of  chilled  wheels  will  often 
outwear  several  pairs  of  steel  wheels  if  they  happen  to  escape 
the  hard  raps  to  which  mine-waggons  are  liable. 

Under  Eyre's  patent,  wheels  are  made  by  forging  a  steel 
bloom  under  a  steam-hammer  into  dies;  they  are  reported  to 
give  great  satisfaction  and  to  be  capable  of  standing  much  knock- 
ing about. 

Wheels  with  two  flanges  are  used  in  the  Festiniog  slate  mines, 
and  are  considered  best  fitted  for  the  work  on  account  of  the  sharp 
turns  in  the  roads. 

Much  difference  of  opinion  and  practice  exists  concerning  the 
attachment  of  the  wheels.  Four  systems  are  in  vogue  :  axles 
fixed  and  wheels  running  loose  on  them;  wheels  fixed  to  the 
axles,  which  run  loose  in  pedestals  attached  to  the  frame  or  to 
the  body  of  the  waggon;  thirdly,  a  combination  of  these  two 
systems — viz.,  wheels  running  loose  on  the  axles  and  axles  run- 


358  ORE  AND  STONE-MINING. 

ning  loose  in  the  pedestals  ;  fourthly,  one  wheel  fast  on  the  axle, 
and  the  other  loose. 

At  a  first  glance  it  might  be  thought  that  it  would  undoubtedly  be 
best  to  follow  the  lead  of  the  great  railways,  and  have  the  wheels 
fixed  to  the  axles,  because  experience  has  shown  that  this  system 
answers  so  well  above  ground.  Nevertheless,  it  must  be  remem- 
bered that  the  conditions  of  underground  roads  are  often  very 
different,  the  curves  are  frequently  of  very  small  radius,  and 
there  is  usually  more  difficulty  in  keeping  the  roads  in  perfect 
order.  By  allowing  the  wheels  and  axles  both  to  be  loose,  the 
Festiniog  miner,  for  instance,  who  may  be  tramming  out  a 
block  of  slate  18  feet  long,  can  slew  his  load  on  the  truck 
and  so  pass  round  sharp  curves  which  would  oppose  an  insur- 
mountable obstacle  if  the  wheels  or  axles  were  fixed.  Loose 
wheels  with  loose  axles  look  clumsy  and  unnatural,  aiid  in  spite 
of  all  that  may  be  said  in  their  defence,  it  is  probable  that  it 
would  in  many  cases  pay  the  mine  owner  to  improve  the  condition 
of  his  roads  and  so  render  a  more  stable  form  of  waggon 
available. 

Lubrication  of  the  bearing  parts  is  too  often  performed  in  a 
perfunctory  and  wasteful  manner,  especially  in  mines  where  the 
waggon  never  comes  to  the  surface  except  for  repairs.  A  little 
grease  or  oil  applied  at  the  beginning  and  in  the  middle  of  the 
shift  is  all  that  is  considered  necessary.  Such  a  procedure  must 
be  defective ;  either  there  is  too  much  of  the  lubricant  at  first,  or 
there  is  too  little  after  the  waggon  has  been  in  use  for  a  time. 

An  automatic  lubricating  apparatus  is  sometimes  fixed  in  the 
road  and  every  waggon  is  greased  in  going  over  it.  The  appa- 
ratus consists  of  a  wheel  placed  in  a  trough  containing  the 
grease,  and  as  each  axle  touches  this  wheel  it  receives  a  little 
lubricant.  A  defect  of  these  lubricators  is  that  when  a  waggon 
is  going  at  great  speed,  as  is  the  case  with  some  systems  of 
underground  haulage,  the  grease  is  flung  about  and  wasted ; 
besides,  where  a  bearing  can  be  greased  in  this  manner  it 
is  necessarily  exposed  to  the  dust  or  mud  of  the  mine,  which 
must  cause  wear  and  friction.  It  is  better  to  provide  constant 
lubrication  and  to  protect  the  bearing  parts  as  much  as  possible 
from  dirt. 

One  method  by  which  this  object  is  attained  is  shown  in  Figs.  410 
and  411,  which  represent  a  waggon  used  at  some  collieries  at  Saint 
Etienne,  in  France,  and  embodying  the  results  of  long  experience. 
The  wheel,  which  is  made  of  steel,  is  placed  under  the  waggon, 
and  the  journal  is  encased  in  a  chamber  kept  full  of  oil.  The 
chamber  has  two  holes  which  serve  for  passing  in  the  linch-pin 
and  putting  in  the  oil.  They  are  afterwards  closed  with  plugs. 
Other  points  which  may  be  noticed  about  this  waggon  are  its 
shape  and  mode  of  construction.  The  body  is  oval  and  made  up 
of  wooden  staves  like  a  barrel. 


HAULAGE  OK,  TRANSPORT. 


359 


As  an  example  of  a  waggon  constructed  entirely  of  steel, 
I  take  a  "tram"  designed  for  the  Llanbradach  colliery  by 
Mr.  Galloway  (Figs.  412  and  413).  The  body  has  the  form 

FIG.  410. 


FIG.  411. 


SCALE  OF  FEET 


SCALE  OF  DECIMETRES 


of  a  very  blunt  oval;  it  is  made  of  sheet  steel  -^  inch  thick, 
stiffened  round  the  top  by  channel  steel.  The  wheels  are  fixed 
to  the  axles,  which  are  kept  constantly  lubricated  by  Stauffer's 
lubricators  placed  immediately  above  them  in  the  hollow  axle- 


360 


ORE  AND  STONE-MINING. 


boxes.     The  empty  waggon  weighs  1 2  cwt.  and  will  carry  2  tons 
of  coal,  when  the  load  is  built  up  higher  than  the  sides. 

When  dealing  with  a  tender  mineral  like  coal,  which  decreases 
in  value  if  knocked  about,  it  is  important  to  reduce  the  effects  of 
bumping  to  a  minimum;  and  with  this  object  in  view  the  waggon 


rests  upon  springs  and  the  bufiers  are  elastic.  The  conse- 
quence is  that  the  waggon  runs  very  smoothly,  and  is  likely  to 
require  less  expenditure  for  repairs  than  one  constructed  in  the 
ordinary  fashion  without  these  appliances.  There  will  likewise 
be  a  diminution  in  the  quantity  of  dust  dropped  on  the  road,  a 
matter  of  moment  in  collieries. 


HAULAGE  OR  TRANSPORT.  361 

The  Hardy  Patent  Pick  Company  makes  self-oiling  pedestals 
for  waggons  with  the  wheels  fast  upon  the  axles  (Fig.  414) ; 
a  is  the  upper  part  of  the  pedestal,  and  b  the  lower  part, 
containing  felt  or  wool  saturated  with  oil.  This  presses  lightly 
against  the  axle  and  keeps  it  oiled 
for  several  weeks,  without  re-  FIG.  414. 

quiring  any  attention. 

It  will  be  seen  from  these 
remarks  that  a  number  of  points 
have  to  be  considered  in  design- 
ing a  mine-waggon.  They  may 
be  summed  up  as  follows  : 

Smallest      weight     compatible 
with  strength. 

Small  height,  if  the  waggon  is  to  be  filled  with  the  shovel. 

Protection  of  the  wheels  from  injury. 

Constant  lubrication. 

Adoption  of  a  uniform  type  of  waggon  for  the  mine. 

Material  which  causes  the  least  expenditure  for  repairs. 

Easy  handling  and  easy  replacement  upon  the  rails. 

In  a  few  exceptional  cases  the  mineral  raised  in  the  mine  does 
not  require  a  box  or  chest.  This  happens  with  slate,  for  the 
blocks  are  brought  up  on  trucks  to  which  they  are  made  fast  by 
chains. 

(c)  Power  used  for  Underground  Transport. 

The  sources  of  power  are  as  follows  : 

1.  Men,  boys,  women,  and  girls. 

2.  Horses,  ponies,  donkeys,  and  mules. 

3.  Gravity  acting  upon  the  material  moved. 

4.  Machines  driven  by  steam,  water,  compressed  air,  and  elec- 

tricity. 

1 .  Human  Labour. — Female  labour  underground  is  prohibited 
by  law  in  the  United  Kingdom,  and  no  doubt  it  is  destined  to 
disappear  in  other  countries.     We  need  only  deal  with  men  and 
boys.     Where   the  passages  are  high  enough  to  take  waggons 
standing  3  feet  above  the  ground,  men  are  usually  employed  for 
drawing  or  pushing  them.     It  is  convenient  to  have  waggons  small 
enough  to  be  handled  by  one  man,  and  also  to  be  put  back  on 
to  the  road  by  one  man,  if  by  chance  they  leave  the  rails. 

The  large  waggons  and  loads  at  Festiniog  require  two  men, 
for  the  load  of  rubbish  commonly  amounts  to  i  f  or  2  tons.  The 
waggon  and  load  together  may  weigh  as  much  as  2j  tons.  The 
men  who  push  out  these  waggons  usually  do  the  loading  also, 
shovelling  in  the  small  pieces  and  lifting  on  the  large  ones. 

2.  Animal  Labour. — Traction  by  horses  or  ponies  is  cheaper 
than  using  human  power,   but   it  is  not  always  practicable  to 


362  ORE  AND  STONE-MINING. 

employ  it.  There  are  many  ore  mines  in  which  it  would  be 
impossible  to  lower  a  horse  down  the  shaft ;  and  even  where  the 
descent  could  take  place,  there  would  often  be  the  further  draw- 
back, that  as  the  work  proceeds  with  comparative  slowness,  owing 
to  the  hardness  of  the  rock,  there  would  not  be  "  stuff"  enough 
broken  in  a  given  time  to  keep  a  horse  constantly  employed  at 
any  particular  level,  whilst  shifting  it  from  one  level  to  another 
would  entail  much  difficulty. 

The  load  drawn  by  a  horse  at  the  Festiniog  slate  mines  is  as 
much  as  eight  waggons,  a  gross  weight  of  20  tons,  or  net  weight  of 
1 6  tons,  along  a  road  with  an  inclination  of  J  inch  per  yard. 

Where  a  mine  is  entered  by  a  shaft,  the  horses  are  stabled 
below  ground,  and  much  care  is  taken  in  many  instances  to 
provide  proper  accommodation  for  them.  The  stables  are  paved 
with  bricks  or  concrete,  sloping  towards  a  gutter ;  each  horse  has 
its  stall,  or  a  loose  board  is  hung  between  every  horse  and  its 
neighbour.  Clean  water  is  at  hand  for  drinking.  At  a  French 
colliery  I  found  the  daily  allowance  of  food  to  be  as  follows : 

Oats ' ....     10  kil.  (22  Ibs.) 

Chopped  hay  from  lentil  and  rye  grass     .       5  kil.  (n  Ibs.) 
Bran 2  kil.  (4-4  Ibs.) 

In  addition  each  horse  had  5  kil.  (n  Ibs.)  of  straw  per  day  as 
litter. 

The  horses  do  not  always  belong  to  the  mining  company ;  at 
Festiniog,  where  the  workings  can  be  entered  by  adits,  horses  are 
hired  from  persons  in  the  district,  who  supply  a  horse  and  man 
for  eight  shillings  per  day,  and  pay  all  the  cost  of  food  and 
stabling. 

3.  Gravity. — In  working  stratified  deposits,  it  is  often  necessary 
or  convenient  to  lower  a  waggon  down  an  inclined  plane  made 
along  the  dip.  At  Mansfeld,  for  instance,  instead  of  maintaining 
a  number  of  levels  at  short  intervals  apart,  it  is  more  economical 
to  reserve  only  a  few  for  traffic,  and  abandon  certain  portions, 
as  already  pointed  out  in  Chapter  YI.  The  waggons  then 
have  to  be  lowered  from  the  working  level  to  one  which  is 
kept  up  as  a  main  roadway.  Inclines  for  this  purpose  have 
two  lines  of  rails,  one  for  the  descending  and  the  other  for 
the  ascending  waggon.  A  wire  rope  or  a  chain  passes  round 
a  pulley  or  drum  at  the  top,  the  axis  of  which  may  be 
horizontal  or  at  right  angles  to  the  plane  of  the  deposit. 
Each  end  of  the  rope  can  be  hooked  on  to  a  waggon,  and 
the  weight  of  the  full  waggon  going  down  suffices  to  raise  the 
empty  one.  The  speed  is  regulated  by  a  brake  on  the  pulley 
or  drum. 

Another  method  of  working  inclines  is  to  make  the  full 
waggon  draw  up  a  weight,  running  on  a  special  line  of  rails, 
which  is  heavy  enough  to  bring  up  the  empty  when  it  de- 


HAULAGE  OR  TRANSPORT.  363 

scends.  In  order  to  economise  space,  the  line  of  rails  for  the 
weight  may  be  made  narrower  than  the  one  used  for  the  waggon, 
and  may  be  laid  between  the  two  main  rails. 

If  the  incline  is  steep,  a  carriage  with  a  horizontal  platform  is 
provided.  The  mine-waggon  is  pushed  on  to  this  travelling 
platform  and  ascends  or  descends  in  its  ordinary  position. 

4.  Machinery. — Underground  haulage  may  be  carried  on 
either  by  travelling  engines  or  stationary  engines. 

Locomotives  fired  with  coal  have  the  great  disadvantage 
of  polluting  the  air  by  the  products  of  combustion,  consequently 
they  are  not  available  unless  the  ventilation  is  very  good,  nor 
unless  there  is  absence  of  inflammable  gases  and  freedom  from 
the  risk  of  setting  fire  to  the  timbering  or  to  the  mineral  itself. 
A  small  locomotive  of  two  horse-power  nominal  is  used  on  an 
i8£  inch  track  in  the  long  adit  of  the  Great  Laxey  lead  and 
zinc  mine  in  the  Isle  of  Man  ;  and  at  Rio  Tin  to  in  Spain  a  much 
larger  engine  plies  in  the  adit  on  a  line  with  a  gauge  of  3  feet  6 
inches. 

Locomotives  driven  by  compressed  air,  carried  in  a  reservoir 
upon  a  tender,  improve  the  ventilation  instead  of  injuring  it,  and 
are  not  a  possible  source  of  danger  from  fire ;  but,  except  in 
special  cases,  they  cannot  be  worked  so  cheaply  as  engines  fired 
with  coal.  However,  the  advantages  they  afford  have  led  to  their 
adoption  in  some  mines ;  Lishman  and  Young's  air  locomotive 
is  employed  in  several  collieries  in  the  North  of  England. 

To  overcome  the  inconveniences  and  dangers  of  engines  of  the 
ordinary  type,  fireless  locomotives  have  been  proposed  and  con- 
structed. That  of  Lamm  and  Franck  has  a  cylindrical  reservoir, 
instead  of  the  boiler,  filled  three-quarters  full  of  water.  The 
reservoir  is  heated  by  steam  from  the  surface,  until  it  is  capable 
of  giving  off  vapour  with  a  pressure  of  235  to  294  Ibs.  per  square 
inch  (16  to  20  atmospheres).  As  the  temperature  and  conse- 
quently the  pressure  of  the  steam  supplied  by  the  reservoir  are 
constantly  falling,  a  regulator  is  interposed  between  the 
reservoir  and  the  steam  cylinder,  which  enables  both  the  pres- 
sure of  the  steam  and  the  amount  of  expansion  to  be  changed  at 
will.  This  arrangement  renders  extra  power  available  if  a  steep 
gradient  has  to  be  mounted. 

Rolland's  fireless  locomotive  is  similar.*  His  reservoir  has  a 
capacity  of  19^  cubic  feet  (0.550  cb.m.),  and  contains  water  at  a 
temperature  of  205°  C.,  or  with  a  pressure  of  235  Ibs.  per  square 
inch  (16  atmospheres).  M.  Rolland  states  that  his  locomotive, 
charged  in  this  fashion,  will  run  for  2  to  2  J  miles  (3  to  4  kms.). 
When  going  at  a  speed  of  2  m.  (6  feet  6f  inches)  per  second,  the 
locomotive  exerts  6  h.p. ;  the  speed  of  a  horse  may  be  taken  as 
0.9  to  i  m.  (3  to  3^  feet).  The  locomotive  ready  for  work  weighs 
three  tons. 

*  B.  und  h.  Zeitung,  1890,  p.  375. 


364  ORE  AND  STONE-MINING. 

As  pointed  out  by  Holland,  the  fireless  locomotives  have  the 
following  advantages  in  addition  to  being  more  economical  : 

No  danger  of  fire  and  no  inconvenience  from  smoke. 

Improvement  in  the  atmosphere  of  the  mine,  owing  to  absence 
of  the  horses  and  their  droppings. 

The  Honiginann  *  locomotive  depends  upon  the  fact  that  a 
solution  of  caustic  soda,  of  a  certain  strength,  will  absorb  steam 
and  give  out  heat.  This  heat  is  utilised  to  convert  hot  water 
into  steam,  which  works  an  engine  and  then  passes  into  the  soda 
solution,  causing  a  further  development  of  heat.  The  process  of 
steam-making  goes  on  thus  of  itself,  until  the  soda  solution 
reaches  a  certain  stage  of  dilution.  The  locomotive  is  re- 
stored to  a  state  of  activity  by  bringing  back  the  solution  to 
the  proper  degree  of  saturation.  This  is  done  by  passing  steam 
from  a  stationary  boiler  through  coils  of  tubes  in  the  reservoir 
containing  the  soda,  a  process  occupying  little  time. 

Experiments  have  been  made,  and  will  be  continued,  with  the 
Honigmann  soda  locomotive,  and  also  with  Krauss'  tunnel 
locomotive,  at  the  Mansfeld  copper  mines. 

Stationary  Engines. — An  enormous  amount  of  underground 
traffic  is  carried  on  by  some  system  in  which  the  power  for 
haulage  is  derived  from  an  engine  placed  above  or  below  ground ; 
but  the  practice  is  far  more  developed  in  collieries  than  in  vein 
mines,  where  the  quantities  of  mineral  to  be  handled  are  as  a  rule 
very  much  smaller. 

With  reference  to  the  application  of  the  power  itself,  the 
various  systems  of  underground  haulage  might  be  classified  thus  : 

Steam   or  water  power   at   the   surface,]  I.  Ropes. 

transmitted    to     machinery    under-  I  2.  Compressed  air. 

ground  by     '    .         .         .         .         .  j  3.  Electricity. 
Water  power  below  ground  driving  the  machinery 

Steam  power  below  ground  driving  th^ 

(2.  Boilers  below  ground; 

Petroleum  engine  below  ground  driving  the  machinery. 

The  subject  of  the  transmission  of  power  has  already  been 
sufficiently  discussed  in  Chapter  IV.,  and  need  not  be  dealt  with 
here,  save  that  it  is  necessary  to  point  out  that  the  conditions 
of  the  problem  are  not  the  same  when  power  has  to  be  applied 
to  haulage,  as  when  it  is  required  in  a  constantly  changing 
working  face.  As  the  mineral  has  to  be  brought  to  the  shaft,  the 
engine  and  its  boiler,  if  necessary,  can  be  placed  in  the  immediate 
vicinity  of  the  pit-bottom  and  the  exhaust  steam  can  be  got  rid  of 
without  interfering  with  the  comfort  of  the  men  or  injuring  the 
condition  of  the  workings.  Proper  rooms  can  be  made  for  the 

*  Official  Catalogue  of  Royal  Mining^,  Engineering,  and  Industrial  Exhi- 
bition, Nervcastle-on-Tyne,  1887,  p.  xxxvi. 


HAULAGE  OR  TRANSPORT.  365 

engine  and  the  boiler,  coal  can  be  brought  down  and  the  ashes 
removed  without  difficulty.  Everything  can  be  arranged  in  a 
permanent  and  substantial  fashion,  so  that  steam  power  may  be 
generated  for  haulage  purposes  below  ground  when  it  would  not 
be  practicable  to  employ  it  for  breaking  down  the  mineral. 
Again,  when  power  has  merely  to  be  transmitted  down  a  vertical 
shaft  in  order  to  work  a  drum  near  the  bottom,  endless  ropes  may 
be  used,  although  they  would  be  quite  out  of  place  if  they  had  to 
be  carried  along  narrow,  low,  and  crooked  levels.  For  subsidiary 
haulage  purposes — that  is  to  say,  for  bringing  trams  from  the 
immediate  vicinity  of  the  workings  to  a  main  line — Galloway 
employs  a  small  engine  with  two  drums  placed  upon  a  waggon, 
which  is  small  enough  to  go  into  the  cage  and  which  will  run 
upon  its  own  wheels  along  the  underground  railways.  It  can 
therefore  be  moved  about  as  required,  and  when  coupled  up  to 
the  compressed  air  main  can  be  set  to  work  immediately  to  haul 
out  trams,  instead  of  employing  horses  for  this  work. 

We  will  suppose  that  the  question  of  the  most  suitable  driving 
machinery  has  been  settled  according  to  the  circumstances  of  the 
case,  and  that  the  miner  has~to  consider  how  he  will  apply  it 
to  the  transport  of  mineral. 

Five  systems  are  in  use  : 

i.  Single  rope- 

ii.  Main  and  tail  ropes, 
iii.  Endless  rope, 
iv.  Endless  chain. 

v.  Electric  railways. 

i.  Single  Rope. — This  system  is  available  with  a  road 
sufficiently  inclined  for  the  empty  waggon  to  run  down  of  itself, 
after  the  load  has  been  brought  up,  and  draw  back  the  rope  with 
it.  One  road  will  suffice,  and  the  machinery  required  will  be 
some  kind  of  drum,  around  which  the  rope  is  coiled,  and  an 
engine  for  driving  it. 

The  drum  is  usually  placed  horizontally ;  it  is  provided  with  a 
brake,  and  there  is  a  disengaging  clutch  by  which  it  can  be  thrown 
in  or  out  of  gear  with  the  engine.  A  pair  of  horizontal  engines, 
which  have  their  cranks  upon  the  drum-shaft,  or  which  drive  it 
by  means  of  a  pinion  and  spur  wheel,  form  the  common  method  of 
applying  the  power. 

The  wire  rope  has  one  end  fixed  to  the  drum  and  the  other 
is  provided  with  a  hook  of  some  kind ;  this  is  attached  to  a  link  of 
the  coupling  chain  of  the  truck  and  the  load  is  drawn  up.  On 
reaching  the  top  of  the  incline  or  engine-plane,  the  waggon  is 
unhooked,  and  either  pushed  or  allowed  to  travel  of  itself,  under 
the  action  of  gravity,  to  the  pit-bottom,  where  the  onsetter  runs  it 
on  to  the  cage  in  which  it  is  raised  to  the  surface. 

An  empty  waggon  is  then  hooked  on  and  run  on  to  the  incline, 
and  the  engine-man,  with  his  brake  under  proper  control,  dis- 


366  ORE  AND  STONE-MINING. 

engages  the  drum  by  means  of  the  clutch  and  lowers  the  load 
without  using  any  steam.  When  worked  in  this  way,  the  incline 
requires  only  one  line  of  rails.  A  series  of  rollers  have  to  be  put 
in  for  the  purpose  of  keeping  the  rope  from  trailing  on  the  ground 
and  of  thus  preventing  much  unnecessary  wear  and  friction.  These 
rollers  are  small  wooden,  cast-iron,  or  steel  cylinders,  often  with  a 
low  flange  at  each  end  to  keep  the  rope  in  its  place ;  they  are  laid 
horizontally  and  are  capable  of  revolving  around  a  horizontal 
spindle.  Care  is,  or  ought  to  be,  taken  to  see  that  they  are  ver}' 
correctly  set  and  that  they  are  well  lubricated,  so  that  they  may 
revolve  freely  when  the  rope  is  drawn  over  them ;  otherwise  the 
strands  are  sure  to  be  worn  down  rapidly  from  rubbing  against 
them. 

The  incline  may  also  be  worked  with  two  lines  of  rails,  after 
the  fashion  of  the  self-acting  inclines ;  and  this  system  has  the 
advantage  of  being  more  economical,  for  the  deadweight  of  the 
loaded  waggon  coming  up  is  balanced  by  the  weight  of  the  empty 
one  going  down.  It  is  not  even  necessary  to  have  two  lines  all 
the  way ;  provided  there  is  a  sufficient  length  of  double  line  where 

FIG.  415. 


the  waggons  meet,  the  incline  can  be  worked  with  a  length  of 
single  line  at  the  top  and  a  similar  length  of  single  line  at  the 
bottom.  To  prevent  a  waggon  from  running  down  in  case  a 
coupling  link  or  the  rope  should  break,  a  safety  appliance,  called 
a  backstay,  may  be  attached  to  it.  It  is  a  sort  of  fork  which  hangs 
behind  the  waggon,  and  just  touches  the  ground ;  -  if  the  rope 
breaks,  it  digs  itself  into  the  road  and  prevents  the  waggon  from 
going  down.  Of  course  it  can  only  be  used  while  the  waggons  are 
being  raised,  bub  it  is  during  the  journey  of  the  loaded  waggon 
that  the  rope  is  most  likely  to  break, 

ii.  Main  and  Tail  Ropes. — On  the  engine  planes  just 
described,  the  empty  waggon  goes  back  under  the  action  of 
gravity ;  but  with  very  slightly  inclined,  flat,  or  undulating  roads 
this  is  impossible.  One  method  of  getting  over  this  difficulty  is 
to  add  a  rope,  called  the  "  tail  rope,"  which  will  draw  the  empties 
back ;  the  rope  which  draws  the  full  waggons  is  known  as  the 
•"  main  rope." 

The  system  is  perhaps  best  explained  by  a  diagram  (Fig.  415) :  a 
is  a  drum  upon  which  is  coiled  the  strong  main  rope ;  b  is  another 
drum  upon  which  is  coiled  the  tail  rope,  passing  round  the  pulley  c. 
The  waggons  are  coupled  together  and  form  the  train  or  "  set," 
which  may  in  reality  consist  of  as  many  as  100  waggons.  Suitable 
clutches  enable  either  drum  to  be  worked  at  pleasure  by  the 


HAULAGE  OR  TRANSPORT.  367 

engine,  while  the  other  is  allowed  to  run  loose  upon  the  shaft. 
Each  drum  has  a  brake,  by  means  of  which  the  rope  can  be 
prevented  from  becoming  too  slack  while  uncoiling  itself.  When 
the  drum  a  is  made  to  revolve  by  the  engine,  the  main  rope 
is  wound  up,  the  drum  b  running  loose,  and  the  train  or  "set" 
is  drawn  from  c  to  a.  Here  the  waggons  are  uncoupled  and 
pushed  to  the  shaft,  or,  better,  the  station  at  a  is  arranged  so 
that  it  is  sufficiently  high  for  the  waggons  to  run  down  of  them- 
selves under  the  action  of  gravity.  A  new  train  of  empties  is 
then  made  up,  the  tail  and  main  ropes  are  attached  to  it  and  the 
drum  b  is  set  in  motion  so  as  to  wind  up  the  tail  rope  and  draw 
the  waggons  into  the  terminus  at  c.  It  will  be  evident  from  a 
glance  at  the  figure  that  the  tail  rope  must  be  twice  as  long  as  the 
main  rope.  As  the  tail  rope  has  simply  a  train  of  empties  to  haul 
out,  it  may  be  made  smaller  than  the  main  rope,  except  in  cases 
where  the  road  has  a  downward  inclination  towards  the  shaft 
sufficient  to  cause  the  loaded  train  to  run  down  of  itself  and  draw 
the  tail  rope  after  it. 

A  single  line  suffices  for  this  system  of  haulage ;  the  main 
rope  lies  in  the  middle  of  the  road,  resting  upon  a  series  of 
horizontal  rollers  similar  to  those  used  upon  ordinary  inclined 
planes.  Where  there  are  curves,  however,  the  rope  must  be 
guided  by  small  vertical  rollers.  The  tail  rope  is  brought  along 
the  side  of  the  road,  or  if  more  convenient,  along  a  separate  road, 
also  resting  upon  rollers  or  pulleys  and  suitably  guided  at  the 
curves.  The  system  is  applicable  to  roads  of  varying  gradients, 
and  arrangements  can  easily  be  made  for  working  branches,  by 
having  a  special  piece  of  tail  rope  in  each  branch  going  round  a 
pulley  at  the  end  of  it.  When  mineral  has  to  be  drawn  away 
from  the  branch,  the  piece  of  tail  rope  on  the  main  road  beyond 
the  junction  is  disconnected,  and  the  piece  belonging  to  the 
branch  is  attached.  Traffic  then  goes  on  as  before,  save  that  the 
train  is  made  up  in  the  branch.  Another  plan  is  to  disconnect 
the  tail  rope  at  the  end  of  the  train,  and  couple  one  end  of  the 
branch  rope  to  the  train  and  the  other  to  the  free  end  of  the 
ordinary  tail  rope.  During  the  running  of  a  train  the  tail  rope 
then  goes  round  the  pulley  at  the  end  of  the  main  road,  passes 
round  another  at  the  junction  of  the  two  roads,  proceeds  along 
the  branch  round  its  terminal  pulley,  and  back  to  a  pulley  which 
again  puts  it  into  the  direction  of  the  main  road. 

The  trains  are  in  a  large  number  of  cases  made  to  run  at  a 
great  speed,  even  as  much  as  10  or  15  miles  or  more  an  hour,  and 
if  by  some  mischance  an  accident  does  happen  from  one  of  the 
waggons  getting  off  the  road,  a  good  deal  of  damage  may  be  done 
to  the  train  and  roadway. 

iii.  Endless  Rope. — A  favourite  method  of  underground 
haulage  is  by  an  endless  rope  passing  round  a  pulley  at  each 
terminus,  and  generally  travelling  continuously  in  the  same 


368  ORE  AND  STONE-MINING. 

direction.  The  rope  is  kept  in  a  state  of  tension  by 
passing  it  round  a  tightening  sheave,  which  in  some  instances 
is  one  of  the  terminal  pulleys.  The  tightening  sheave  or 
pulley  is  carried  by  a  frame  running  upon  wheels,  and  is 
constantly  drawn  back  by  a  heavy  weight.  The  necessary  grip  of 
the  rope  is  obtained  by  coiling  it  several  times  round  the  driving 
drum,  or  around  a  driving  pulley  with  grooves  and  a  second 
grooved  pulley  close  by ;  the  rope  wraps  itself,  for  instance,  upon 
three  half  circumferences  of  one  pulley  and  twTo  of  the  other. 
The  speed  of  an  endless  rope  is  usually  from  two  to  three  miles  an 
hour,  though  instances  might  be  cited  of  as  low  a  speed  as  one 
mile  an  hour.  The  endless  rope  system  admits  of  so  many  modi- 
fications that  it  is  necessary  at  once  to  classify  them  before 
entering  into  any  details.  We  may  begin  by  making  two  broad 
divisions :  * 

Waggons  attached  singly  at  intervals  along  the  rope. 
Waggons  attached  in  groups  or  trains  (sets). 

Waggons  Attached  /Singly. — Two  distinct  lines  of  rails  are 
required,  because  there  is  a  constant  stream  of  full  waggons 
coming  out  to  the  shaft  and  a  constant  stream  of  empties  going 
into  the  workings. 

This  class  has  two  subdivisions : 

Hope  above  the  waggons. 
Hope  below  the  waggons. 

"When  the  rope  is  above  the  waggons,  no  rollers  are  necessary 
except  at  the  curves.  Several  modes  of  attaching  the  waggon  to 
the  rope  are  in  use. 

If  the  gradient  is  all  up  hill  a  very  simple  clip  is  sufficient. 
The  rope  is  made  to  rest  in  a  fork  on  the  waggon,  and  as  it 
is  bent  slightly  out  of  the  line  of  pull  when  in  motion,  it  is 
held  tightly  enough  by  friction  to  draw  along  the  load.  If  the 
gradient  varies,  a  fork  is  put  on  each  end  of  the  waggon,  or  a 
screw  clip  is  employed ;  this  resembles  a  pair  of  tongs,  the  jaws 
of  which  are  brought  tightly  together  by  a  screw  worked  by  a 
handle,  and  hold  the  rope  with  a  firm  grip. 

Another  common  attachment  is  by  a  piece  of  chain  6  or  8  feet 
long  with  a  hook  at  each  end.  A  boy  puts  one  hook  into  an  eye 
on  the  drawbar  of  the  waggon,  and  giving  the  other  end  of  the 
chain  four  turns  round  the  rope  makes  it  fast  in  the  hook. 
To  detach  a  waggon  the  boy  presses  down  the  chain  near  the 
waggon,  takes  out  the  hook  from  the  drawbar,  and  then  unwinds 
the  other  end  from  the  rope.  After  a  little  practice  the  boys 
become  very  dexterous  in  this  hooking  on  and  off,  and  perform 

*  The  classification  and  some  of  the  information  is  taken  from  the 
Catalogue  of  the  Eoyal  Mining,  Engineering,  and  Industrial  •  Exhibition, 
Newcastle-on-Tyne,  1887,  p.  xxxiv. 


HAULAGE  OR  TRANSPORT. 


369 


FIG.  416.         FIG.  417. 


these  operations  with  great  rapidity.  If  there  is  a  downward 
gradient  the  waggon  would  outrun  the  rope,  and  it  is  necessary 
to  put  a  chain  at  the  rear  end  as  well  as  in  front. 

When  the  rope  is  below  the  waggons,  rollers  are  required  on 
the  road,  similar  to  those  already  described  for  engine-planes 
and  main  and  tail  ropes.  The  attachment  to  the  rope  is  made 
by  some  form  of  clip.  At  the  Hodbarrow  iron  mine  in  Cumber- 
land, Rice's  clutch  (Figs.  416  and  417)  has  been  used  for  many 
years  with  good  results.  The  rope  can  be  put  in  or  taken  out 
sideways  after  raising  the  sliding  piece 
A  as  far  as  the  projecting  pin.  The  clip 
is  hung  by  its  hook  on  to  the  waggon 
and  the  rope  is  lifted  in ;  the  motion  of 
the  rope  draws  the  clip  a  little  away 
from  the  vertical,  and  this  slight  devia- 
tion of  the  groove  from  the  line  of  pull 
gives  sufficient  grip  for  haulage. 

The  number  of  clips  or  clutches  is 
very  great,  and  it  would  be  useless  to 
attempt  to  describe  them  all  within  the 
limits  of  this  work. 

An  advantage  of  this  system  is  the 
smooth  and  regular  manner  in  which  it 
works.  The  waggons  are  attached  at 
intervals  of  about  20  yards  or  even  less, 
and  they  arrive  without  the  bustle  of 
a  long  train.  The  men  and  boys  are 
kept  constantly  employed,  but  have  ample  time  for  doing  all  that 
is  required  of  them.  If  a  waggon  goes  off  the  line,  it  is  true 
that  a  large  number  of  the  succeeding  ones  may  be  thrown  off 
too,  before  the  damage  becomes  known ;  but  the  absence  of  a  high 
speed  tends  to  render  the  consequences  less  perilous  than  with 
the  fast-running  trains  of  the  main  and  tail  rope  system. 

Waggons   Attached   in  Groups   or   Trains   (Sets). — As  in   the 
previous  case  there  are  two  subdivisions : 

Eope  above  the  waggons. 
Hope  below  the  waggons. 

The  former  of  these  two  methods  is  very  easily  understood. 

For  instance,  several  waggons  may  be  coupled  together  and  the 

train  thus  formed  is  connected  to  the  moving  rope  by  a  short 

piece  of  chain  with  two  hooks,  in  the  manner  described  for  a 

single  waggon.     Other  attachments  are  of  course  available. 

The  second  subdivision  admits  of  a  great  many  varieties : 

(a)  Single  road,  with  a  siding  or  sidings  for  the  full  train  to 

pass   the   empty  one. — (ai)  Single   central  siding. — The  rope  is 

arranged  in  the  form  of  a  double  loop,  represented  diagramma- 

tically  by  the  dotted  line  (Fig.  418) ;  S  denotes  the  shaft  end  of  the 

2  A 


370  ORE  AND  STONE-MINING. 

haulage  system,  W  the  end  near  the  workings,  and  C  the  central 
siding.  The  full  lines  indicate  the  railroads.  When  moving  in 
the  manner  shown  by  the  arrows,  the  rope  brings  out  a  train  of 
full  waggons  from  the  workings,  and  takes  in  a  train  of  empties 
from  the  shaft.  On  arriving  at  the  central  siding  the  rope  is 
stopped,  the  empties  are  shunted  on  to  the  siding,  and  the 

FIG.  418. 


train  of  full  waggons  is  attached  to  the  part  of  the  rope  which 
has  just  brought  in  these  empties.  The  empties  are  shunted 
back  on  to  the  main  line  and  attached  to  the  part  of  the  rope 
just  used  for  bringing  out  the  full  waggons.  On  reversing  the 
motion  of  the  engine,  the  empties  proceed  to  the  workings  and 
the  full  train  travels  to  the  shaft. 

(02)  One  or  more  sidings.  —  The  two  ropes  (Fig.  419)  lie 
within  the  road,  except  at  the  sidings,  each  of  which  has  one  of 
them.  There  are  points  at  the  ends  of  the  sidings,  for  diverting  the 
trains  on  to  the  proper  roads.  Each  train  has  a  special  truck,  or 

FIG.  419. 


bogie,  in  front,  upon  which  rides  a  conductor.  It  is  his  business 
to  pick  up  with  a  hook  the  rope  he  requires,  and  grip  it  with  his 
clutch ;  his  train  then  moves  along  on  to  the  main  line  till  he 
comes  to  a  pass-by.  A  boy  attending  to  the  points  makes  the 
train  take  the  proper  line,  and  if  one  train  arrives  a  little  too 
early  for  the  passing,  the  conductor  loosens  his  clutch  and  brings 
his  train  to  a  standstill  until  the  other  train  has  gone  by.  He 
can  then  proceed  along  the  main  road  till  it  becomes  necessary  to 
cross  a  second  train. 

(/3)  Two  roads  formed  by  three  rails  with  one  or  more  sidings 
for  the  passing  of  trains. — One-half  of  the  endless  rope  (Fig.  420) 

FIG.  420. 


lies  in  the  middle  of  one  track,  and  the  other  in  the  middle  of  the 
other  track.  The  trains  pass  as  they  did  in  the  previous  system  ; 
but  there  is  the  advantage  that  no  points  are  required. 

(y)  Two  entirely  separate  lines  of  rails. — In  this  case  (Fig.  421) 
no  intermediate  sidings  or  points  are  necessary,  for  each  train  has 
its  own  line,  and  the  services  of  the  conductor  can  be  dispensed 
with. 


HAULAGE  OK  TRANSPORT.  371 

In  making  a  choice  between  these  various  methods,  much 
depends  on  the  nature  of  the  roads.  At  some  mines  it  may 
be  difficult  to  keep  a  road  open  of  the  width  necessary  for 
•two  separate  lines  of  rails,  or  indeed  for  one;  so  that  a  system 
which  can  be  worked  by  a  single  line  with  occasional  sidings  will 
be  preferred.  Besides,  it  may  be  necessary  to  introduce  mechanical 
haulage  into  a  mine  laid  out  originally  for  horse  traffic,  and  the 
expense  of  making  a  second  road  might  be  fatal  to  a  double-line 
system,  in  spite  of  its  manifest  advantages".  ' 

FIG.  421. 

iv.  Endless  Chain. — This  may  be  looked  upon  as  a  variety 
of  the  previous  system,  a  chain  being  substituted  for  the  rope. 
The  chain  is  usually  made  to  ride  upon  the  waggons,  and  as 
•each  link  lies  in  a  plane  at  right  angles  to  that  of  its  neigh- 
bour, it  is  easy  to  devise  a  simple  catch  or  clip.  A  common 
one  is  a  bar  with  a  fork  at  the  top,  which  is  attached  to  one 
•end  of  the  waggon.  The  waggon  is  pushed  under  the  chain,  which 
is  sagging  down  a  little,  so  that  a  link  lying  vertically  drops  into 
the  fork;  the  next  link  will  catch  against  the  clip  and  set  the 
waggon  in  motion.  On  arriving  at  the  terminus  the  chain  is 
raised  by  a  pulley,  and  so  lifted  out  of  the  fork.  The  waggons 
are  attached  singly. 

v.  Electric  Railways. — In  the  previous  four  cases  we 
have  been  dealing  with  the  transmission  of  power  by  a  moving 
rope  or  chain,  we  now  come  to  a  totally  different  solution  of  the 
problem — viz.,  the  transmission  of  power  by  a  wire  or  wires  to  a 
motor  which  runs  on  a  track  and  draws  a  train  of  cars  after  it. 

As  an  example  *  of  an  electric  railway,  I  may  take  one  which 
has  been  running  for  some  years  at  the  Neu-Stassfurt  mine, 
where  potassium  salts  and  rock  salt  are  the  object  of  the  workings. 
The  underground  railway  runs  for  a  distance  of  nearly  1000  yards 
^(900  m.),  along  the  strike  of  the  deposit ;  a  cable  is  brought  down 
the  shaft,  and  there  are  two  insulated  conductors  hung  from  the 
roof  of  the  level ;  one  conveys  the  current  to  the  electric  locomotive 
by  means  of  a  slide,  dragged  along  by  a  small  rope,  and  the 
other  has  a  similar  slide  for  the  return.  The  road  in  this  case  is 
perfectly  horizontal,  and  the  locomotive  draws  a  train  made  up 
of  20  waggons.  An  empty  waggon  weighs  400  kil.,  and  takes  a 
load  of  750  kil.;  20  full  waggons  make  up  therefore  a  total 
weight  of  23  tons.  The  locomotive  weighs  2*1  tons,  consequently 
the  total  weight  of  the  train  is  about  25  tons.  The  steam 
•engine  for  driving  the  dynamo  at  the  surface  is  of  about  20 

"*  MS.  notes  and  B.  und  h.  Zeitung,  1888,  p.  300. 


372  ORE  AND  STONE-MINING. 

horse-power.  The  locomotive  is  3  feet  J  inch  wide  by  4  feet  1 1 
inches  high,  and  8  feet  9  inches  long  between  the  buffers  (930  mm. 
by  1500  mm.  by  2670  mm.)  and  the  centres  of  the  axles  are 
i8f  inches  (480  mm.)  apart.  The  gauge  of  the  road  is  24!  inches 
(628  mm.),  and  the  diameter  of  the  driving  wheels  13!  inches 
(350  mm.).  The  locomotive  is  made  alike  at  both  ends,  with  a 
seat  for  the  driver,  so  that  he  can  travel  in  either  direction,  with- 
out having  to  turn  it  round.  It  takes  a  train  five  minutes  to  run 
the  900  metres. 

The  cost  compares  favourably  with  that  required  for  tramming 
by  men  or  horses,  and  in  1888  the  figures  given  were  as  follows  : 


— 

Electric  Eailway. 

Horses. 

Men. 

Cost  of  haulage  per  ton  ) 
per  kilometre             .  j 

Pfennige. 
12-9 

Pfennige. 
l6'00 

Pfennige. 
34*20 

Speaking  roughly  these  figures  are  i^d.  per  ton  per  kilometre 
for  the  electric  railway,  i^d.  for  horses,  and  ^d.  for  men. 

Comparing  the  electric  railway  with  horse  traffic,  there  are 
other  advantages  besides  that  of  cost.  The  mine  is  kept  much 
sweeter  and  cleaner,  from  the  absence  of  the  droppings  of  the 
horses,  and  in  this  particular  case,  the  animals  would  suffer  in 
their  hoofs,  from  constantly  walking  in  the  damp  salt. 

The  Neu-Stassfurt  line  is  not  working  under  the  most  favour- 
able conditions  for  economy,  because  it  cannot  be  kept  fully 
employed  ;  and  considering  the  rapid  strides  which  have  been  made 
during  the  last  few  years  in  electric  transmission,  it  is  certain 
that  a  line  put  up  nowadays  would  furnish  more  favourable 
results.  The  line  shown  by  Messrs.  Siemens  and  Halske,  at  the 
late  Frankfort  Exhibition,  had  a  single  wire  hung  from  the  roof 
of  the  level,  and  the  current  was  brought  down  to  the  motor  on 
the  locomotive  by  a  running  pulley  held  by  a  balanced  arm,  which 
ensured  contact,  although  the  distance  between  the  wire  and  the 
locomotive  was  not  always  exactly  the  same.  The  return  current 
travelled  along  the  rails. 

At  Greenside  mine  in  Westmoreland,  there  are  two  wires  along 
the  roof  of  the  level,  one  for  bringing  the  current  to  the  electric 
locomotive  and  the  other  for  the  return. 

VI.  CONVEYANCE  BY  BOATS.— This  is  a  very  excep- 
tional method  of  conveying  mineral  underground  at  mines ;  but 
it  needs  mention  to  make  the  subject  complete. 

In  this  country  there  is  an  adit  level  at  the  Tankerville 
and  Bog  mines  in  Shropshire,  known  as  the  "  Boat  level,'* 
because  the  ore  was  carried  in  boats  to  its  mouth,  a  distance  in 
some  places  of  if  miles.  As  the  adit  had  been  driven  with  too 
great  a  fall  originally,  it  was  necessary  to  have  small  locks  under- 


HAULAGE  OR  TRANSPORT.  373 

ground,  and  so  subdivide  the  whole  length  into  several  parts,  one 
slightly  above  the  other.  This  level  now  serves  simply  as  a 
drainage  tunnel. 

At  the  Dorothea  Mine,  near  Clausthal  in  the  Hartz,  there  is  a 
level  more  than  400  yards  below  the  surface,  along  which  there 
was  at  one  time  a  large  amount  of  traffic  by  boats.  The  level  is 
10  feet  high,  by  7  feet  wide,  with  5  feet  of  water  in  the  bottom. 
The  boats  used  on  this  underground  canal  were  about  31  feet 
long,  4^  feet  wide  outside,  and  3  feet  deep.  The  part  used  for 
holding  the  ore  had  a  capacity  of  about  220  cubic  feet ;  the  load 
was  5  or  6  tons  of  ore,  and  a  full  load  would  bring  the  edge 
of  the  boat  within  6  inches  of  the  water.  The  boat  was 
propelled  by  the  men,  who  pushed  with  their  feet  against  the  roof 
of  the  level. 

TRANSPORT  ABOVE  GROUND. 

In  commencing  this  chapter  I  said  that  it  would  be  convenient 
in  this  place  to  take  the  subject  of  conveyance  of  mineral  above 
ground,  though,  strictly  speaking,  it  would  not  come  until  after  the 
consideration  of  methods  of  raising  ore  and  rubbish  to  the  surface. 
This  part  of  the  subject  must  be  treated  in  a  somewhat  summary 
manner  for  want  of  space,  and  also  for  the  reason  that  much  that 
has  been  said  about  underground  traffic  will  apply  in  the  case  of 
conveyance  above  ground,  indeed  the  same  heads  may  be  taken, 
with  the  addition  of  a  seventh — transport  by  aerial  ropeways. 

1.  Shoots  made  of  timber,  with  the  wearing  parts  protected  by 
iron,  can  be  applied  in  places  where  there  is  a  sufficient  amount  of 
fall.     In  a  hilly  country  it  may  sometimes  be  worth  while  sinking 
a  shaft  solely  for  the  purpose  of  using  it  as  a  means  of  dropping 
ore  to  a  lower  level. 

2.  Flow  along  Pipes  is  made  use  of  on  a  very  extensive  scale 
for  the  transport  of  natural  gas,  petroleum  and  brine. 

The  Annual  Report  of  the  Philadelphia  Company,  one  of  the  six 
companies  supplying  Pittsburg,  shows  that  in  the  year  1885  it  had 
331  miles  of  mains  and  distributing  pipes,  which  brought  in  the 
natural  gas  from  distances  of  22  to  24  miles;  at  that  time  it  was 
estimated  that  there  were  at  least  500  miles  of  pipes  coming  into 
the  city.  The  mains  vary  in  diameter  from  3  inches  to  30 
inches,  the  largest  sizes  being  made  of  cast-iron  and  the  others  of 
wrought-iron.  There  are  more  pipes  of  8  inches  in  diameter 
than  of  any  other  size,  and  the  mains  are  made  to  increase  in 
diameter  as  they  approach  the  city,  in  order  to  reduce  the 
pressure  of  the  gas.  Many  of  the  wells  when  shut  would  have  a 
pressure  of  500*  Ibs.  per  square  inch,  and  even  when  the  pressure 
is  far  lower  than  this,  it  is  necessary  to  reduce  it  in  order  to 
prevent  leakage,  which  means  not  only  diminished  profits  to  the 

*  C.  A.  Ashburner,  "  The  Geologic  Distribution  of  Natural  Gas  in  the 
United  States."— Trans.  Amer.  Inst.  M.E.,  vol.  xiv.  1886,  p.  428. 


374  OEE  AND  STONE-MINING. 

company,  but  also  danger  to  the  consumer.  In  the  town  the- 
pressure  nowhere  exceeds  13  Ibs.,  and  in  many  of  the  mains  it  is 
not  more  than  6  or  8  Ibs.,  whilst  in  the  low  pressure  mains  it  is 
only  4  or  5  ozs.  per  square  inch. 

Another  case  of  conveyance  of  gas  by  pipes  is  seen  at  the  bore- 
holes furnishing  carbonic  acid  gas  in  Germany ;  under  its  natural 
pressure  the  gas  flows  through  wrought-iron  pipes,  either  to  the 
works  where  it  is  compressed  into  the  liquid  state,  or  to  those 
where  it  is  utilised  for  the  manufacture  of  white  lead. 

Crude  petroleum,  which  either  rises  naturally  to  the  surface  or 
is  pumped  up,  has  to  be  refined  before  it  can  be  utilised  com- 
mercially, and  it  has  been  found  convenient  in  many  districts  to- 
send  the  oil  to  the  refineries  by  pipe-lines.*  Pumps  are  employed 
for  forcing  the  oil  through  the  long  lines  of  pipes,  as  there  is  no 
natural  pressure  in  this  case.  The  United  Pipe-lines  Company  in 
America  had,  in  1886,  "over  4000  miles  of  piping  and  500 
reservoirs,  each  holding  from  20,000  to  30,000  barrels,"  f  and 
probably  now  there  are  more  than  5000  miles  of  pipe-lines  in  the 
United  States. 

The  pipe-line  from  the  Lima!  °il  district  of  Ohio  to  Chicago  is 
210  miles  long;  the  pipes  are  8  inches  in  diameter,  and  each 
piece  22  feet  long.  The  cost  of  the  pipes  alone  was  estimated  to 
be  $7000  per  mile,  and  the  total  cost  of  the  undertaking,  in- 
cluding the  pumps  and  reservoirs,  $2,250,000. 

Another  of  the  great  American  pipe  lines  §  connects  Olean  in 
the  Bradford  oil-field  with  New  York  City.  It  consists  of  two 
lines  of  6-inch  pipes,  more  than  300  miles  in  length,  and  it  is 
divided  into  1 1  separate  sections.  At  each  station  there  are  two 
tanks  and  a  pump  ;  when  one  tank  is  receiving  oil,  the  other  is 
supplying  it  to  the  pump  for  transmission  to  the  next  station 
further  east,  a  week  being  required  to  complete' the  journey.  As 
the  lines  of  pipes  follow  the  irregularities  of  the  surface,  ample 
pumping  power  has  to  be  provided.  One  of  the  Worthington 
pumps  ||  on  this  line  exerts  a  pressure  of  900  Ibs.  per  square 
inch,  and  is  capable  of  delivering  1,^00,000  gallons  in  24  hours. 

Mr.  Marvin  also  mentions  a  pipe-line  at  the  Burmese  oil-fields 
made  of  lacquered  bamboos,  for  taking  the  oil  from  the  wells  to- 
the  river.  Modest  as  this  line  appears  compared  with  the  great 
undertakings  just  described,  it  is  nevertheless  an  advance  upon 
the  old  plan  of  putting  the  petroleum  into  earthen  jars,  and 
carting  it. 

In  this  country,  brine   is  sent  by   pipe-lines  from  the   wells 

*  Kedwood,  "Petroleum  and   its  Products." — Journ.  Soc.  Arts,  xxxiv. 
1886,  p.  832;  and  "  Cantor  Lectures,"  published  separately,  p.  30. 
f  The  Times,  29th  September,  1886. 
\  Engineering,  vol.  xlv.  1888,  p.  439. 

§  C.  Marvin,  "  England  as  a  Petroleum  Power,"  London,  1887,  p.  19. 
||  Eng.  Min.  Jour.,  vol.  li.  1891,  p.  745. 


HAULAGE  OR  TRANSPORT.  375 

to  convenient  places  for  evaporation  or  to  alkali  works,  where 
it  is  used  in  making  carbonate  of  soda  by  the  Solvay  process. 
Lastly,  it  has  been  suggested  that  the  solution  of  the  "  caliche,"  or 
raw  nitrate  of  soda,  should  be  sent  down  in  pipes  to  the  coast 
for  evaporation,  instead  of  performing  this  process  in  the  arid 
desert  in  the  neighbourhood  of  the  diggings. 

The  flow  of  mineral  in  suspension  in  water  along  troughs 
(lauiiders),  or  channels  made  in  the  ground,  or  pipes,  is  a  process 
which  may  be  seen  on  the  dressing-floors  at  metalliferous  and  other 
mines,  as  well  as  at  china  clay  works.  At  the  Mechernich  lead 
mines  the  waste  from  the  preliminary  dressing-floors  is  forced  by 
plunger-pumps  through  a  large  pipe  to  pyramidal  boxes,  in 
which  the  water  is  separated  from  the  sand,  so  that  it  may  be 
used  over  again. 

Though  not  a  true  flow,  I  may  here  mention  the  conveyance  of 
a  mineral  for  short  distances  by  revolving  screws  in  troughs 
("  screw  conveyors "),  which  serve  to  transport  a  mineral  from 
one  part  of  a  factory  or  dressing-floors  to  another. 

3.  Human   Labour. — In   mountainous   districts   where    the 
inhabitants  are  accustomed  to  carry  their  provisions,  their  hay 
or  other  agricultural  produce  upon  their  backs,  it  is  not  unnatural 
to  find  ore  transported  in  the  same  way  from  the  mine  to  the 
dressing-works.     Not   many   years   ago,  gold   ore   was  regularly 
carried  to  the  little  amalgamating  mills  in  the  Italian  Alps  on 
women's  backs.     The  ordinary  load  for  a  woman  down  hill  was 
100  Ibs.    (45   kil.).      If  the  woman  took  tools  or  materials   up 
hill,  the  load  was  naturally  less,  and  amounted  to  about  75  Ibs. 
(34  kil.).     The  ore  was  carried  in  a  basket  or  creel  (scivera),  an 
appliance  to  which  every  peasant-girl  had  been  accustomed  from 
early  youth. 

Ore  may  be  moved  from  one  part  of  the  dressing-floors  to  another 
by  hand-barrows.  These  are  merely  rectangular  trays  or  boxes, 
with  a  pair  of  handles  in  front  and  a  pair  behind.  The  hand- 
barrow  requires  two  persons  to  carry  it  (.Fig.  61 1). 

Carriage  on  the  head  is  met  with  in  some  countries. 

4.  Conveyance  by  Sledges. — Sledges  drawn  by  men  or  horses 
still  survive  in  some  hilly  districts.     Even  in  Wales  at  the  present 
day,  manganese  ore  is  sometimes  brought  down  from  the  mine  to 
the  nearest  cart-road  in  this  primitive  fashion.     But  it  is  a  toil- 
some and  unsatisfactory  method  of  transport,  and  justifiable  only 
in  the  case  of  trials,  which  have  not  yet  proved  a  sufficient  amount 
of  ore  to  warrant  the  construction  of  a  tramway  or  a  ropeway. 

5.  It  is  by  wheeled  conveyances  that  minerals  are  most 
commonly  transferred  from  one  part  of  a  mine  to  another,  or 
from  the  mine  to  a  railway  or  port  of  shipment.     Wheelbarrows 
are  applicable  for  distances  measured  by  yards,  such  as  one  may 
have  on  dressing-floors,  and  carts  are  sometimes  the  only  available 
means  of  transport  for  one  or  two. hundred  miles ;  but  the  traflic 


376  ORE  AND  STONE-MINING. 

should  be  conducted  in  some  cheaper  fashion,  by  railways  for 
instance,  as  soon  as  possible. 

It  is  not  necessary  to  go  over  all  the  old  ground  with  regard  to 
rails,  sleepers,  points  and  crossings ;  suffice  it  to  say  that  though 
the  surface  railway  resembles  the  underground  one,  it  is  generally 
better  kept ;  first,  because  its  defects  are  more  palpable  to  every 
one  by  daylight  than  when  seen  by  the  glimmer  of  a  candle,  and 
secondly,  because  there  are  fewer  difficulties  in  laying  it  properly 
and  keeping  it  in  order. 

At  the  surface  as  well  as  underground  we  have  self-acting 
inclines,  and  traction  by  locomotives  and  ropes. 

Self-acting  inclines  stand  the  miner  in  good  stead  in  hilly 
countries.  There  are  either  two  entirely  separate  roads,  one  for 
the  full  waggon  going  down  and  the  other  for  the  empty  which  is 
being  brought  up,  or  there  are  three  rails  with  a  pass-by  in  the 
middle,  or  even  a  single  road,  except  at  the  pass-by.  The  incline 
is  worked  by  a  drum  at  the  top,  placed  most  commonly  on  a 
horizontal  axis,  and  of  course  provided  with  a  brake. 

As  examples  of  large  inclines,  I  may  refer  to  those  erected 
by  the  "  Societe  Franco-beige  des  Mines  de  Somorrostro,"  *  for 
bringing  down  iron  ore  to  their  railway,  which  then  conveys  it  to 
the  port  of  Bilbao.  The  lower  of  the  two  planes  is  737  yards 
(674  m.)  long,  with  an  average  inclination  of  30°,  the  maximum 
inclination  being  36°  near  the  top.  It  is  worked  by  steel  wire 
ropes  i  J  inch  (38  mm.)  in  diameter,  which  are  coiled  around  two 
conical  drums,  united  by  their  bases  and  having  a  mean  diameter 
of  i6J  feet  (5  in.).  In  order  to  regulate  the  descent  of  the  trains, 
the  drums  are  connected  by  gearing  with  an  air-brake,  identical 
in  principle  with  the  fly  of  a  clock  (Fig.  422).  It  is  composed  of  four 
straight  vanes  made  of  wood  and  iron,  about  6J  feet  (2  m.)  wide, 
and  16  J  feet  (5  m.)  in  diameter  outside.  Twelve  waggons  coming 
from  the  mine  are  coupled  together  so  as  to  form  a  train,  and 
when  it  starts  down  the  incline,  the  air-brake  begins  to  revolve 
and  soon  develops  a  considerable  amount  of  resistance  as  the  speed 
increases ;  the  consequence  is  that  the  train  descends  with  an 
almost  uniform  velocity.  The  strap-brake  on  the  drum  simply 
serves  to  moderate  the  speed  if  necessary  and  to  stop  the  train  ; 
but  in  no  case  is  much  power  required  to  work  it.  The  train 
makes  a  journey  in  three  minutes,  and  it  takes  three  minutes  to 
make  up  and  couple  on  a  train ;  therefore  there  is  one  train 
every  six  minutes,  and  as  each  waggon  contains  two  tons,  the 
quantity  delivered  by  each  train  is  24  tons,  or  with  ten  trains  an 
hour  the  quantity  per  day  of  ten  hours  will  be  2400  tons.  By 
increasing  the  number  of  waggons  in  each  train,  the  day's  work 

*  Exposition  Universelle  de  1889.  Note  sur  ^Exposition  de  la  Societe 
Franco-beige  des  Mines  de  Somorrostro  en  1889.  Paris,  1889,  p.  II.  Les 
Orandes  usines  de  Turgan.  August,  1889,  p.  50.  Forges  et  Ateliers  de  Con- 
struction de  Mme.  Vve.  Taza-  Villain. 


HAULAGE  OR  TRANSPORT. 

FIG.  422. 


377 


3/8  ORE  AND  STONE-MINING. 

may  be  run  up  to  2600  tons.  The  fan-regulator  has  the  advan- 
tage of  saving  the  wear  of  the  ordinary  strap-brakes  and  of 
rendering  the  speed  uniform.  If  nothing  but  a  strap-brake  was 
used,  there  would  be  a  very  great  amount  of  friction,  which  might 
cause  the  wooden  shoes  to  take  fire ;  in  any  case  it  would 
throw  a  great  strain  upon  the  machinery,  and  involve  the  risk 
of  a  serious  accident  if  it  happened  to  break.  The  fan- 
regulators  avoid  all  these  difficulties ;  but  they  must  be  made 
very  strong,  as  they  have  to  counteract  a  considerable  amount  of 
vis  viva — at  the  particular  incline  mentioned  no  less  than  42 & 
horse-power.  I  have  dwelt  somewhat  upon  this  fan-regulator, 
as  it  has  been  found  extremely  serviceable  at  Somorrostro,  though 
little  known  elsewhere. 

Locomotives  burning  coal  can  be  used  without  inconvenience, 
and  effect  a  great  saving  in  most  places,  when  compared  with 
horse  traffic.  At  the  Festiniog  slate  mines,  small  locomotives 
running  on  a  track  with  a  23^-inch  gauge  are  employed  for 
drawing  trains  of  rubbish  to  the  tips ;  the  total  weight  of  a  train 
may  be  as  much  as  80  tons.  As  the  men  who  are  removing 
rubbish  from  the  underground  or  surface  workings  are  paid  by 
the  ton,  the  loads  have  to  be  weighed.  When  the  trains  are 
drawn  by  a  horse,  it  is  necessary  to  stop  each  time  a  waggon  is 
brought  on  to  the  weigh-bridge ;  but  when  the  locomotive  is  used, 
the  train  runs  so  smoothly  that  the  waggons  can  be  weighed 
during  their  passage,  without  any  halts  being  made.  This  is 
a  small  advantage  it  is  true,  but  it  saves  time  and  consequently 
money,  and  should  therefore  be  noticed. 

The  endless  rope  and  the  endless  chain  conveying  single 
waggons  at  stated  intervals  are  both  in  favour,  either  for  trans- 
porting the  valuable  mineral  to  any  required  spot,  or  for  taking 
the  waste  to  the  tip  or  "  dump." 

An  example  of  the  former  system  may  be  seen  at  the  De 
Beers  *  diamond  mine,  South  Africa,  where  the  gem -bearing  rock 
has  to  be  exposed  to  the  action  of  the  atmosphere  for  some  months 
in  order  to  make  it  crumble  away  and  become  ready  for  the  pro- 
cess of  washing.  Large  areas  have  to  be  covered  with  the  "  blue," 
and  cheap  haulage  is  a  matter  of  importance.  The  depositing 
floors  commence  at  a  point  a  mile  from  the  mine  and  extend 
for  three  miles  to  the  east  and  one  mile  to  the  west.  The  main 
line  is  three  miles  in  length  and  it  has  two  branches,  one  a  mile 
long,  and  the  other  three-quarters  of  a  mile  long.  The  rope  is 
driven  by  a  horizontal  engine,  with  two  cylinders,  each  14  inches 
in  diameter,  and  having  a  stroke  of  3  feet.  It  is  |  inch  in 
diameter  and,  as  is  very  commonly  the  case  elsewhere,  it  has  an 
iron  instead  of  a  hempen  core,  in  order  to  prevent  a  reduction  of 

*  De  Beers  Consolidated  Mines,  Limited.  Second  Annual  Eeportfor  the 
Year  ending  ^ist  March,  1890,  p.  17. 


HAULAGE  OR  TRANSPORT.  379 

section  when  it  is  subjected  to  continued  tension.  It  is  carried 
on  the  steel  trucks,  which  can  be  tipped  on  either  side,  as  the  body 
is  supported  on  two  trunnions  (H,  Fig.  442).  The  device  for 
attaching  the  rope  to  the  waggon  is  very  simple ;  the  rope  lies 
in  a  fork  or  "  jockey,"  which  is  slightly  out  of  the  direct  line  of 
traction.  The  jockey  is  free  to  turn  in  a  socket  on  the  truck, 
and  the  slight  bend  given  to  the  rope  is  sufficient  to  afford  the 
necessary  grip,  even  in  going  up  an  incline  of  i  in  20.  If  the 
"  blue  "  has  to  be  deposited  at  a  point  nearer  the  mine  than  the 
terminus,  the  part  of  the  rope  beyond  the  place  where  the  waggons 
are  taken  off  is  supported  by  pulleys. 

Horses  are  employed  to  draw  the  trucks  from  the  main  rope 
haulage  lines  to  the  places  on  the  floors  where  they  have  to  be 
tipped. 

The  endless  chain  has  been  chosen  for  bringing  down  the  ore 
from  some  of  the  mines  of  the  Somorrostro  Company,*  in  a  part 
where  self-acting  inclines  cannot  be  used  because  there  is  not  a 
descent  all  the  way.  A  second  reason  for  adopting  this  system 
was  the  fact  that  it  admits  of  considerable  changes  in  the  amount 
of  traffic,  by  altering  the  speed  of  the  chain  and  the  distance 
between  two  successive  trucks.  It  further  allows  branch  lines 
to  be  taken  off  from  the  main  one.  At  Somorrostro  there  are 
in  all  very  nearly  two  miles  (3000  m.)  of  endless  chain  haulage. 

The  greatest  difference  of  level  between  the  highest  point  at 
the  Sol  mine  and  the  terminus  at  the  station  of  Cadegal  is  802 
feet  (244-60  m.),  and  on  one  part  of  the  line  the  gradient  is  as 
high  as  29*5  per  100  or  i  in  3-4.  The  fall  is  so  great  that  the 
chain  requires  no  power  but  gravity  to  work  it ;  in  fact,  it  is 
necessary  to  use  brakes  to  oppose  the  vis  viva.  Strap-brakes  are 
employed  in  the  same  manner  as  they  are  on  the  inclines  just 
described,  solely  for  the  purpose  of  stopping  the  chain.  The  danger 
of  depending  entirely  upon  such  brakes  for  working  inclines  has 
already  been  pointed  out,  and  a  uniform  speed  is  maintained  by 
affixing  fan-regulators  working  in  water.  They  are  chosen  in  this 
case  in  preference  to  the  fans  working  in  air,  because  the  latter 
must  revolve  at  a  great  velocity  in  order  to  be  efficient,  and  there- 
fore could  not  be  applied  to  the  slow  chain  haulage  without  gearing, 
which  would  introduce  complications.  These  hydraulic  governors 
are  like  the  air-regulators  in  principle,  except  that  the  blades  are 
immersed  in  water ;  the  speed  of  the  chain  can  be  adjusted  with 
the  greatest  nicety  by  altering  the  quantity  of  water  in  the  tank 
in  which  the  blades  work,  and  so  introducing  the  amount  of 
resistance  required. 

The  usual  speed  at  which  the  chain  is  run  is  5  feet  (1*5  m.)  per 
second,  but  it  can  be  raised  to  6  feet  6  inches.  The  chain  is  made 
of  J-inch  (22  mm.)  iron,  which  corresponds  to  about  19^  Ibs.  per 

*  Exposition  Universelle  de  1889.     Op.  cit.,  p.  15. 


380  OEE  AND  STONE-MINING. 


yard  (yS26  kil.  per  metre).  The  last  section,  however,  has  harder 
work,  and  the  chain  is  of  i-inch  iron  (26  mm.)  and  weighs  28 
Ibs.  per  yard  (14  kil.  per  metre).  Each  waggon  holds  iyf  cwt. 
(900  kil.)  of  ore,  and  when  the  waggons  are  arranged  2  7  yards 
(25^2  m.)  apart,  the  chain  haulage  is  capable  of  transporting  2500 
to  2600  tons  of  ore  a  day,  in  addition  to  a  certain  amount  of 
rubbish  which  is  tipped  before  arriving  at  the  port. 

6.  Conveyance  of  Mineral  by  Boats  from  one  part  of  a 
mine   to   another  is  exceptional  ;  but  transport  by  canal  or  sea 
to  the  consumer  is  common,  and  is  chosen  whenever  available 
on  account  of  its  comparative  cheapness.     It  is  of  the  utmost 
importance  when  dealing  with  large  quantities  of  mineral  to  have 
cheap  and  rapid  methods  of  shipping  it.    At  Huelva,  the  shipping- 
port  of   the  Rio  Tinto   mines,  the  trains  of   ore  are  drawn  on 
to  a  part  of  the  pier  which  has  just  enough  inclination  to  make 
a  truck  run    down   of   itself.      A  workman   then    uncouples   a 
truck  and  allows  it  to  run  opposite  a  shoot,  which  leads  to  the 
hold  of  the  vessel  lying  alongside  the  pier.     The  truck  is  emptied 
by  opening  the  bottom  and  letting  the  contents  drop  into  the 
mouth  of  the  shoot.     The  bottom  is  then  closed  and  the  truck  is 
allowed  to  run  on  a  little  further,  when  it  is  shunted  back  on  to 
a  side  line,  and  made  to  join  the  train  of  empties  ready  to  be 
drawn  back  to  the  mine.    After  the  locomotive  has  once  hauled  a 
train   on   to  the  proper  part  of  the  pier,  the  discharge  of  its 
contents  into  the  ship  proceeds  very  rapidly  and  requires  the 
attendance  of  only  one  man. 

The  arrangements  are  so  perfect  that  500  tons  can  easily  be 
loaded  in  an  hour,  but  naturally  a  good  deal  of  time  is  lost  in 
shifting  the  steamers  and  berthing  them.  The  greatest  amount  of 
work  in  loading  at  Huelva  pier  has  been  a  little  over  3000  tons 
in  a  single  day.  A  steamer  has  been  known  to  come  into  Huelva 
harbour  by  one  tide,  and  leave  by  the  next  with  a  cargo  of  1500 
tons  of  ore. 

The  Somorrostro  Company  loads  its  iron  ore  at  Bilbao  in  a 
similar  manner.  The  Company  has  three  wharves,  at  each  of 
which  2000  tons  can  be  shipped  in  a  day  ;  indeed  a  ship  of  1490 
tons  has  been  loaded  in  six  hours. 

7.  Aerial  Ropeways.  —  These  ropeways  may  be  divided  into 
five  classes  : 

a.  Single  supporting  rope,  with  or  without  a  hauling  rope. 

b.  Endless  rope,  which  is  the  supporting  rope  and  hauling  rope 

at  the  same  time. 

c.  Two  supporting  ropes  and  an  endless  rope  for  hauling  the  load. 

d.  Double  endless  travelling  rope  or  chain. 

e.  Telpherage  line. 

a.  Lines  erected  on  the  first  of  these  principles  may  be  seen  in 
hilly  countries.  An  iron  or  steel  wire  rope  is  stretched  across  a 
valley,  and  forms  the  rail  .supporting  the  load,  which  is  put  into 


HAULAGE  OR  TRANSPORT.  381 

a  sack  and  hung  on  by  a  grooved  pulley.  If  the  heights  of  the 
departure  and  receiving  stations  are  properly  arranged,  the  load 
on  going  down  the  slope  acquires  enough  momentum  to  bring  it 
up  to  the  station  on  the  other  side,  without  rushing  in  too 
violently.  The  objection  to  this  system  is  that  the  sacks  and  the 
pulleys  have  to  be  carried  back  by  men  or  women,  but  it  has  the 
merit  of  simplicity  and  cheapness.  By  the  addition  of  a  small 
hauling  rope  on  a  drum,  the  method  is  available  for  steep  moun- 
tain sides ;  the  load  is  lowered  with  use  of  the  brake,  and  the  drum 
is  worked  to  draw  up  the  empties  along  the  supporting  rope. 

b.  In  this  system  there  is  an  endless  rope,  supported  by  pulleys 
on  strong  wooden  or  iron  posts  placed  at  suitable  intervals,  which 
is  set  in  motion  by  any  available  source  of  power.     Suspended  from 
the  rope  are  the  buckets  or  other  vessels  in  which  the  mineral  is 
carried.     The  buckets  maybe  detachable  at  pleasure  or  they  may  be 
fixed.    The  former  plan  is  the  one  brought  out  by  Hodgson  in  1869, 
The  bucket  or  other  receptacle  is  suspended  by  an  iron  hanger 
from  a  grooved  block  of  wood  which  rests  upon  the  rope.     The 
carrying  block  has  a  spindle  with  a  small  grooved  pulley,  which 
can  be  made  to  run  upon  a  rail  at  each  terminus  and  so  let  the 
rope  move  on  without  the  load.     The  bucket  is  filled  from  a  shoot 
or  hopper  while  hanging  on  the  rail  at  the  loading  terminus.     A 
workman  then  pushes  it  along  the  rail  until  the  carrying  block 
is  taken  up  by  the  rope,  which  is  always  in  motion ;  the  load  now 
travels  along  suspended  from  the  rope,  the  carriers  being  con- 
structed so  as  to  pass  over  the  pulleys.     On  reaching  the  unload- 
ing terminus,  the  carrying  block  is  again  shunted  on  to  a  rail,  and 
the  bucket  is  tipped  by  lifting  up  the  catch  which  had  kept  it  from 
turning  about  pivots ;  after  having  been  put  into  position,  it  is 
brought  round  to  the  point  where  the  rope,  after  passing  round  a 
terminal  pulley,  is  about  to  begin  its  journey  back  to  the  loading 
station.     Here  it  is  shunted  on  to  the  rope  and  travels  along 
with  it. 

One  great  disadvantage  of  this  system,  in  the  case  of  steep  in- 
clines, is  that  the  carriers  may  slip  upon  the  rope,  and  that  the 
loads  either  fall  off  or  do  damage  in  some  other  way.  To  over- 
come this  difficulty,  some  of  the  constructors  of  aerial  ropeways 
attach  the  loads  to  a  clip  which  is  tightly  fixed  to  the  rope.  The 
clip  must  be  of  such  a  nature  that  it  will  pass  the  supporting 
sheaves  or  pulleys.  When  the  inclination  is  sufficient,  an  aerial 
line  of  this  description  will  work  automatically,  the  weight  of  the 
full  loads  being  enough  to  draw  up  the  empties. 

c.  The  third  system  has  two  fixed  ropes,  which  serve  as  aerial 
rails  and  act  solely  as  supports,  and  an  endless  travelling  rope, 
to  which    the  loads  are  made  fast  at    pleasure.     It   resembles, 
therefore,  the  endless  rope  haulage,  of  which  mention  has  been 
made  for  underground  work,  save  that  the  rails  are  above  the 
load  instead  of  being  below  it. 


382 


ORE  AND  STONE-MINING. 


FIG.  423. 


Ropeways  working  upon  this  plan  have  been  perfected  of  late 
years  by  Otto  and  by  Bleichert  in  Germany,  where  they  are 
commoner  than  in  this  country.  They  are  constructed  for  distances 
of  from  2  to  8  or  even  10  miles,  with  a  carrying  capacity  of  600  to 
800  tons  per  day  of  10  hours.  The  separate  loads  may  vary  from 
J  cwt.  to  i  ton  each. 

The  points  to  be  considered  are  : 

Carrying  rope  and  vessel. 

Posts  or  standards. 

Hauling  rope  and  attachments. 

Terminals  and  their  shunting  arrangements. 

The  kind  of  cable  used  on  the  most  recent  lines  erected  on  the 
Otto  system  *  is  that  known  as  "  locked  coil  wire  rope,"  the  con- 
struction of  which  is  explained  in  the  next  chapter  (Fig.  451).  It 
has  the  advantage  of  presenting  a  perfectly  smooth  surface,  ad- 
mirably adapted  for  the  running  of  the  grooved  pulleys  by  which 
the  load  is  suspended.  The  vessel  in  which  the  mineral  is  conveyed 
may  be  any  convenient  form  of  bucket 
or  box,  supported  by  pivots  around 
which  it  can  be  easily  tipped,  or  the 
actual  mine-waggons  may  be  slung  up 
and  the  ore  carried  in  them. 

Each  box,  bucket,  or  waggon,  is  at- 
tached to  a  hanger  suspended  from  a 
spindle  placed  midway  between  two 
grooved  pulleys  or  wheels,  which  rest 
on  the  rope  (Fig.  423). 

The  posts  or  standards  are  constructed 
of  wood  or  iron,  sometimes  with  two, 
and  sometimes  with  four  legs,  suitably 
stiffened  by  braces  and  held  in  position 
by  guy  ropes  or  rods  (Figs.  424  and  425). 
The  four-legged  standards  are  used  for 
heavy  loads  or  long  spans.  The  distance 
between  the  standards  varies  according 
to  the  nature  of  the  country,  and  is  often 
about  30  to  60  yards ;  but  where  the 
country  is  much  broken  by  ravines,  these  short  spans  are  unat- 
tainable without  standards  of  an  impracticable  height,  and  the 
cable  is  then  made  to  stretch  across  very  long  intervals  without 
intermediate  supports.  Spans  of  550  yards  (500  m.)  are  not 
unknown. 

The  hauling  rope  must  be  very  flexible,  and  is  made  of  fine  steel 
wire  with  a  hempen  core.  The  mode  of  attachment  of  the  load 
varies  with  the  gradient  of  the  line.  If  the  gradient  is  less  than 

*  J.  Pohlig,  "  Aerial  Kopeways,  Otto  System."— Tram.  Amer.Inst.  M.E., 
vol.  xix.  1891,  p.  760. 


HAULAGE  OR  TRANSPORT. 


383 


i  in  6,  the  amount  of  friction  necessary  for  gripping  the  rope 
tightly  can  be  obtained  by  bringing  it  between  two  flat  iron 
discs  and  clamping  them  together  with  a  screw.  One  of  these 
discs  is  rigidly  attached  to  the  hanger,  and  the  tightening  screw 
of  the  other  can  be  loosened  automatically  by  providing  it  with 
a  projecting  lever,  which  comes  in  contact  with  a  stop  at  the 
terminus. 

If  the  gradient  is  between  i  in  6  and  i  in  3,  the  discs  are  made 


FIG.  424. 


FIG.  425. 


VOODEN    STAN 


with  corrugated  instead  of  smooth  surfaces.  When  the  gradient 
exceeds  i  in  3,  another  device  has  to  be  employed  ;  projecting 
knobs  are  inserted  into  the  rope  at  regular  intervals,  and  on 
meeting  with  properly  arranged  stops  upon  the  loads  they  cause 
them  to  travel  along.  Figs.  426,  427  and  428  show  the  details 
of  the  arrangement. 

Each  terminus  is  provided  with  an  iron  rail  which  is  fixed 
so  as  to  meet  the  rope  where  thev  buckets  have  to  be 
loaded  or  unloaded  ;  by  suitably  arranging  the  end  of  the 
rail,  the  load  passes  quite  smoothly  from  it  to  the  rope  and  vice 
versd. 


384 


ORE  AND  STONE-MINING. 


An  example  of  one  of  the  Otto  ropeways  is  given  in  Fig.  429, 
which  is  a  section  of  the  line  put  up  for  the  Sheba  Gold  Mining 

FIG.  426, 


FIG.  427. 


Company,  Limited,  Barberton  ;  it  is  2\  (4-4  kil.)  miles  long,  and 
will  carry  150  tons  per  day  of  10  hours.  The  maximum  incline 
is  i  in  i '6,  and  the  greatest  span  1480  feet  (451  m.). 

FIG.  429. 


Tntermtdialf 
'/cnsim  drur 


Intermediate 
\7ension  Clear 


VERTICAL  SCALE 


IOO  M.  O   100  2OO  3OO  4OO  50O  METRES 


HORIZONTAL  SCALE. 


A  line  erected  in  Southern  Spain  for  carrying  iron  ore  is  9*69 
miles  (15*6  kil.),  long,  divided  into  four  independent  sections. 
The  greatest  span  is  918  feet  (280  m.),  but  on  an  average  the  sup- 


HAULAGE  OR  TRANSPORT. 


385 


porting  posts  are  only  44  yards  (40  m.)  apart.  The  hauling  rope 
is  made  to  travel  at  the  rate  of  100  yards  (90  m.)  a  minute, 
and  deliver  two  buckets,  each  containing  7  cwt.  (350  kil.)  in  that 
time.  This  means  a  carrying  capacity  of  1200  buckets  or  420 
tons  per  day  of  10  hours.  The  line  has  also  been  worked  with 


two  shifts  of  8  hours  each,  and  has  transported  900  tons  in  that 
time.  The  total  cost  of  this  line,  which  was  surveyed,  erected 
in  a  very  difficult  country,  and  ready  to  start  in  ten  months, 
was  ,£26,000  ;  and  it  has  been  worked  at  a  cost  of  is.  $d.  per  ton, 
which  includes  all  that  is  spent  for  labour,  maintenance  and 
repairs. 

At  the  Menzel  colliery  in  Upper  Silesia,  500  to   700  tons  of 
coal  are  carried  in  ten  hours  a  distance  of  r6  miles,  for  i  \d.  per 

2  B 


386  ORE  AND  STONE-MINING. 

ton  per  mile,  including  wages,  repairs,  interest  on  capital  and 
depreciation  of  plant.  Fig.  430  shows  part  of  the  line  at  Gottes- 
segen  colliery,  Upper  Silesia.* 

A  line  carrying  iron  ore  in  Luxembourg  is  3  miles  long,  and 
transports  300  tons  of  iron  ore  in  10  hours  at  a  cost,  again  in- 
cluding all  expenses — viz.,  wages,  repairs,  interest  on  capital,  and 
depreciation  of  plant,  of  ^\d.  per  ton,  or  i^d.  per  ton  per  mile. 

d  and  e.  Ropeways  worked  by  these  systems  are  rare. 

*  "Otto  Patent  Kopeway."—  The  Engineer,  vol.  Ixvii.  1889,  p.  115. 


(     387     ) 


CHAPTER  VIII. 
HOISTING  OB  WINDING. 

Motors,  drums,  and  pulley-frames. — Kopes,  chains,  and  attachments. — 
Kibbles,  skips,  and  cages. — Keps,  guides,  signals. — Safety  appliances, 
detaching-hooks,  safety-catches,  automatic  stopping  gear — Pneumatic 
hoisting. 

BY  hoisting  is  meant  raising  the  minerals  from  the  underground 
workings  to  the  surface.  In  speaking  of  the  subject  generally, 
it  is  more  correct  to  say  hoisting  than  winding,  because  this 
latter  term  implies  the  use  of  the  rope,  which  is  not  quite 
universal.  As  already  explained  in  the  last  chapter,  there  is  no 
clear  line  of  demarcation  between  haulage  and  winding.  In 
the  typical  case  of  a  vertical  shaft  and  a  nearly  horizontal  level, 
it  is  easy  to  make  the  distinction ;  but  when  the  mineral  is 
drawn  up  through  inclines,  the  name  given  to  the  process 
depends  upon  local  custom.  Thus,  part  of  the  shaft  at  a  Cornish 
tin  mine  is  inclined  at  an  angle  of  only  15^°  from  the  horizontal, 
and  nevertheless  the  work  of  drawing  up  the  ore  is  always  called 
winding. 

In  a  few  districts  carriage  on  the  back  still  survives;  in 
Sicily,  for  instance,  much  of  the  sulphur  rock  is  brought  to 
the  surface  by  boys  on  their  backs  up  rough  paths,  or  steps 
cut  in  the  ground.  As  lately  as  ten  years  ago,  I  found  slate 
being  brought  up  on  the  back  in  the  Moselle  district.  In 
Mexico  and  in  China,  too,  the  same  method  is  pursued  in 
some  silver  and  other  mines.  However,  this  barbarous  mode 
of  raising  mineral  is  simply  mentioned  for  the  purpose  of  con- 
demning it. 

The  regular  method  of  bringing  a  mineral  to  the  surface  is  to 
draw  it  up  a  shaft  or  an  incline  by  means  of  a  rope.  The  subject 
is  such  a  wide  one  that  it  must  be  treated  under  different  headings 
as  follows:  (i)  Motors,  drums  and  pulley-frames;  (2)  Hope, 
or  chain ;  attachments  of  the  rope;  (3)  Receptacle  for  the  mineral 
or  waste  rock  ;  (4)  Other  indispensable  appliances,  guides,  signals, 
keps  ;  (5)  Safety  appliances. 

i.  MOTORS,  DRUMS,  AND  PULLEY-FRAMES.— 
Motors — As  in  other  departments  of  mining,  the  motor  employed 
may  be  worked  by  animal  power,  or  by  an  engine  driven  by 
water,  steam,  compressed  air,  petroleum  or  electricity. 


388  ORE  AND  STONE-MINING. 

(a)  Animal  Power. — The  simplest  contrivance  for  winding  is  a 
pulley  supported  by  some  suitable  frame  above  the  shaft ;  a  bucket 
is  attached  to  the  end  of  a  rope  hanging  down  the  shaft,  whilst  the 
other  end,  passing  over  the  pulley,  is  drawn  by  men  or  women  : 
they  simply  walk  away  from  the  shaft  and  haul  up  the  bucket. 
Oil  wells  are  sunk  in  Burmah  by  this  primitive  method  of 
hoisting. 

The  usual  method  of  applying  human  power  is  by  a  windlass. 
This  well-known  appliance  consists  of  a  wooden  cylinder,  about 
eight  inches  in  diameter,  provided  with  two  iron  handles  and 
supported  by  two  upright  posts  which  are  suitably  stayed.  A 
sliding  bar,  which  can  be  drawn  out  either  above  or  below  the 
cylinder,  serves  to  hold  one  of  the  handles,  when  required. 

In  this  country,  the  ordinary  windlass  is  used  for  shallow 
sinkings  of  twenty,  thirty,  or  forty  yards  in  depth,  such  as  are 
made  in  commencing  work  at  a  mine,  or  in  effecting  a  communi- 
cation between  two  levels ;  but  in  countries  where  mining  is 
less  advanced,  and  where  labour  is  cheaper,  the  windlass  may 
form  the  sole  means  for  hoisting  from  depths  of  a  hundred  and 
even  two  hundred  yards.  Thus,  for  instance,  at  Boryslaw,  in 
Galicia,  it  is  reckoned  that  six  or  seven  thousand  shafts  have 
been  sunk  during  the  last  thirty  years,  for  the  purpose  of  working- 
ozokerite,  to  an  average  depth  of  one  hundred  yards,  by  human 
labour  ;  four,  five,  and  even  six  men  and  women  may  be  seen 
working  the  Boryslaw  windlass.  In  the  neighbouring  country  of 
Roumania,  oil  wells  are  sunk  in  like  manner.  The  windlass  is  used 
either  with  one  or  two  buckets  ;  in  the  latter  case  the  labour 
is  lightened,  for  the  weight  of  the  empty  bucket  going  down 
balances  the  dead  weight  of  the  bucket  coming  up  with  a  load  of 
rock. 

As  a  rule  too  little  attention  is  paid  to  the  state  "of  the  axles 
and  bearings.  Windlasses,  like  other  machines,  cannot  be  worked 
with  economy  unless  means  are  taken  to  prevent  unnecessary 
friction,  which  is  sure  to  arise  unless  the  axles  and  bearings 
are  kept  perfectly  true ;  this  fact  should  be  specially  borne  in 
mind  when  the  mine-owner  is  employing  expensive  human 
power. 

The  capstan  is  an  unusual  form  of  winding  machine  at  mines  ; 
it  differs  from  the  windlass  by  having  its  cylinder  vertical.  As  an 
instance  of  its  use,  I  may  mention  the  little  underground  quarries 
at  Swanage  in  Dorsetshire,  where  blocks  of  stone  are  drawn 
up  inclines  by  means  of  capstans  turned  with  bars,  after  the 
manner  of  those  used  on  board  ship. 

When  a  horse  is  employed  in  the  place  of  men,  the  bucket, 
attached  to  a  rope  passing  over  a  pulley,  is  sometimes  drawn  up 
by  making  the  animal  walk  away  from  the  shaft.  The  framework 
and  pulley  constitute  what  is  called  a  whipsiderry. 

Animal  power  is  usually  applied  by  means  of  a  machine  called 


HOISTING  OR  WINDING.  389 

a  horse-whim.  It  may  be  looked  upon  as  a  gigantic  capstan, 
worked  by  horses,  mules,  or  donkeys.  It  consists  of  an  upright 
axle,  usually  of  timber,  supported  at  the  bottom  by  an  iron  pin 
or  pivot,  which  works  in  a  hole  in  a  large  stone,  forming  a  primi- 
tive foot-block.  A  horizontal  beam,  known  as  the  driving  beam, 
is  attached  to  the  axle,  and  above  it  comes  a  hollow  wooden 
cylinder  or  drum,  around  which  the  rope  is  coiled,  proper  project- 
ing horns  or  flanges  being  provided  to  prevent  it  from  slipping 
off. 

The  other  end  of  the  axle  works  in  an  iron  socket,  carried 
by  a  great  horizontal  beam,  known  as  the  span-beam,  which  is 
supported  by  two  legs.  In  this  country  the  horse-whim  is  not 
roofed  over,  and  it  forms  a  prominent  feature  in  many  mining 
districts;  where  the  weather  is  more  severe,  a  house  becomes 
necessary.  The  winding  rope  is  coiled  several  times  around  the 
drum,  and  both  ends,  after  passing  over  pulleys,  hang  down  the 
shaft ;  when  the  horse  walks  round,  one  bucket  is  raised  and 
the  other  lowered. 

Before  the  introduction  of  steam,  the  horse- whim  was  a  very 
important  means  of  winding ;  and  in  countries  where  water- 
power  is  lacking,  coal  dear,  and  fodder  cheap,  it  still  performs  very 
useful  services.  As  many  as  six  to  eight  horses  may  be  harnessed 
to  a  horse-whim  for  the  purpose  of  working  it. 

(6)  Water. — I  will  now  pass  on  to  the  engines  worked  by  water, 
steam,  compressed  air,  petroleum,  or  electricity. 

When  the  water-wheel  is  used  for  hoisting,  it  is  necessary  to 
have  means  of  reversing  the  motion,  in  order  to  raise  or  lower 
the  rope  at  pleasure.  Two  methods  may  be  employed :  A 
double  wheel  with  the  buckets  fixed  in  opposite  directions ;  a 
single  wheel  provided  with  suitable  gearing  or  belts.  The  double 
wheel  is  frequently  seen  underground  in  Germany  ;  it  has  sluices 
(hatches)  which  will  turn  the  water  on  to  either  side,  and  there  is 
a  brake  for  controlling  the  motion.  The  winding-drum  is  placed 
•on  the  shaft  of  the  water-wheel,  and  according  as  the  water  is 
turned  on  to  the  right-hand  or  to  the  left-hand  side,  the  wheel 
revolves  one  way  or  the  other. 

When  gearing  is  employed,  a  bevel-wheel  upon  the  shaft  of  the 
water-wheel  drives  a  pair  of  bevel-wheels,  facing  each  other,  which 
run  loose  upon  the  shaft  of  the  drum.  By  means  of  a  suitable 
clutch  either  of  them  can  be  brought  into  firm  connection  with 
the  drum-shaft,  and  so  made  to  drive  it  in  the  required  direc- 
tion. 

Fig.  43 1  shows  the  method  adopted  at  Great  West  Van  Mine 
in  Cardiganshire  by  Messrs.  Urquhardt  and  Small.  A,  Girard 
turbine  ;  B,  belt  driving  the  shaft  of  two  pulleys  C  D ;  E  and  F, 
pulleys  loose  upon  the  shaft ;  G,  clutch ;  H,  handle  working  clutch ; 
I,  pinion  driving  spur-wheel  on  drum  J  J  ;  K,  brake  strap ;  L,  pin 
connected,  when  required,  to  "bob  "  of  pumps.  The  belt  from  C 


390 


ORE  AND  STONE-MINING. 


FIG.  431. 


to  E  is  straight,  and  that  from  D  to  F  is  crossed ;  therefore  the 
two  pulleys  E  and  F  are  always  revolving  in  opposite  directions. 
According  as  E  or  F  is  made  fast  to  the  shaft  by  the  clutch  G, 
the  pinion  I  turns  the  drum  one  way  or  the  other. 

(c)  Steam. — Steam-engines  em- 
ployed for  winding  have  usually 
two  cylinders,  either  vertical  or 
horizontal;  the  latter  are  preferred. 
In  some  mining  districts,  notably 
in  Cornwall,  one  finds  a  single 
vertical  cylinder  working  a  beam 
by  which  motion  is  communicated 
to  a  fly-wheel;  but  for  rapid  work 
it  is  necessary  to  have  more  com- 
mand of  the  engine  than  can  be 
furnished  by  a  machine  of  this 
kind. 

It  was  the  fashion  at  one  time 
to  put  a  pinion  upon  the  crank- 
shaft and  a  spur-wheel  upon  the 
drum  shaft ;  nowadays  for  quick 
winding  the  drum  is  placed  upon 
the  same  shaft  as  the  cranks.  This 
is  called  working  on  the  first  motion, 
whereas  if  gearing  is  used  the 
method  is  said  to  be  on  the  second 
motion.  In  any  case  the  engine 
must  be  provided  with  an  adequate 
brake,  and  where  the  drum  is 
worked  by  gearing,  it  is  necessary 
to  have  a  brake  upon  the  drum 
shaft,  because  otherwise  there 
would  be  no  means  of  arresting 
the  descent  of  the  load  in  case  of 
fracture  of  some  of  the  cogs. 
Although  many  winding  engines 
work  without  expansion,  automatic 
expansion  gear  is  common,  and 
some  of  the  engines  are  arranged 
so  that  the  commencement  and  end 
of  the  run  shall  be  worked  with 

the  full  power  of  the  steam,  and  the  middle  of  the  run  expan- 
sively. Compound  engines,  and  indeed  triple  expansion  engines, 
have  been  erected  for  winding  purposes,  though  the  advisability 
of  employing  them  is  questioned  by  some  mining  engineers ; 
while  fully  admitting  the  value  of  this  principle  in  the  case  of 
engines  which  are  working  constantly,  such  as  those  used  for 
pumping,  they  contend  that  it  is  not  advisable  to  complicate 


HOISTING  OR  WINDING. 


FIG.  433. 


machinery  which  is  performing  very  irregular  work,  and  is  being 
continually  stopped  and  started. 

Compound  engines  have,  however,  been  adopted  recently  for 
winding  at  Llanbradach  Colliery,  near  Cardiff,  by  Mr.  Galloway. 
The  two  cylinders  on  each  side  are  arranged  tandem  fashion 
(Figs.  432  and  433).  A,  high  pressure  cylinder;  B,  low  pressure 
cylinder;  C,  drum. 

(d)  Compressed  Air. — Compressed  air  is  largely  employed  when 
the  hoisting   engine   has   to  be   placed  underground,  and  it  is 
especially  suitable  for 

sinking      intermediate  •FlG>  432- 

shafts  (winzes).  Com- 
pact and  handy  forms 
of  engines  are  supplied 
by  various  makers ; 
many  of  them  are 
similar  to  the  steam 
winches  used  on  board 
ship,  and  consist  of 
two  cylinders  driving 
a  pinion  which  works 
a  spur  -  wheel  placed 
upon  the  same  shaft  as 
the  drum. 

Occasionally,  as  for 
instance  at  the  Long 
Tunnel,  Walhalla,  in 
Victoria,  all  the  hoist- 
ing of  a  mine  is  done 
by  a  compressed  air 
engine.  The  reason  for  this  choice  at  the  Long  Tunnel  was  the 
fact  that  lode  was  reached  by  a  long  adit,  in  which  compressed 
air  appeared  to  be  the  most  convenient  method  of  transmitting 
power  from  a  motor  at  the  surface. 

(e)  Electricity. — Winding   by   electricity   is   as  yet   in   its  in- 
fancy;   but,   no  doubt,  in  the  course  of  a   few  years,   we  shall 
hear  more  of  this  convenient  method  of  conveying  power  to  the 
place  where  it  is  to  be  used.     It  is  easy  to  understand  that  an 
electrical  motor  can  be  applied  to  the  drum  used  for  winding, 
its  rapid  motion  being  reduced  to  a  suitable  speed  by  means  of 
gearing. 

Drums. — A  winding  drum  is  usually  a  mere  revolving  cylinder, 
around  which  the  rope  coils  itself.  It  is  formed  of  two  centre- 
pieces keyed  to  the  shaft,  each  carrying  arms,  to  which  are 
attached  rings.  Supported  by  these  rings  are  pieces  of  plank 
or  plates  of  iron  or  steel,  which  build  up  a  hollow  cylinder,  the 
length  and  diameter  of  which  depend  upon  the  importance  of  the 
plant.  In  large  mines  one  may  see  drums  20  and  even  30  feet  in 


392 


ORE  AND  STONE-MINING. 


diameter ;  with  a  drum  of  20  feet,  10  revolutions  mean  coiling  or 
uncoiling  209  yards  of  rope. 

A  drum  constructed  for  Llanbradach  Colliery  is  a  hollow 
cylinder  17  feet  in  diameter,  and  8  feet  wide.  In  Figs.  434  and 
435,  A  is  a  cast-iron  centre-piece;  B  B  are  arms  made  of  H -steel, 
to  which  are  riveted  the  crossbars  of  channel-iron  C.  The  skeleton 
formed  in  this  way  is  covered  with  plates  of  steel  D,  f  inch  thick, 
which  are  fixed  with  countersunk  rivets  to  J-iron  E,  where  they 
meet.  F  is  the  flange  to  prevent  the  rope  from  slipping  off  the 
drum,  and  G  the  wrought-iron  ring  upon  which  the  brake 
acts.  A  novelty  introduced  by  Mr.  Galloway  is  the  arrange- 
ment for  keeping  a  reserve  length  of  rope  to  supply  the  loss 


FIG.  434. 


FIG.  435. 


caused  by  successive  re-cappings.  Inside  the  main  drum  is  the 
hollow  cast-iron  cylinder  H,  capable  of  turning  independently. 
When  a  new  rope  is  put  on,  50  yards  of  it  are  coiled  upon 
H,  the  bolts  of  the  clip  I  are  fastened,  and  the  remainder 
is  wound  round  the  main  drum.  After  re-capping  the  rope 
at  the  end  of  two  months,  it  is  easy  to  unloose  the  clip  and 
draw  out  what  is  required.  The  drum  is  constructed  as  light  as 
possible,  in  order  to  prevent  power  from  being  wasted  in  starting 
and  stopping  an  unnecessarily  heavy  mass.  The  shaft  is  20  feet 
in  diameter  and  550  yards  deep  to  the  first  seam  of  coal  intended 
to  be  worked  ;  but  it  will  be  probably  made  600  to  630  yards  deep 
in  time.  The  engine  (Fig.  432)  is  expected  to  raise  200  tons  of 
coal  per  hour  with  two  mine  waggons  in  each  cage,  each  waggon 
carrying  2  tons. 

An  objection  urged  against  the  plain  cylindrical  drum  is  that 
it  in  no  way  compensates  for  the  change  of  work  required  of  the 


HOISTING  OR  WINDING.  393 

engine  during  the  different  phases  of  the  act  of  winding.  To  make 
this  plain,  suppose  one  end  of  the  rope  to  be  at  the  bottom  of  the 
shaft  with  the  full  load  attached  to  it,  whilst  the  other  end  is  at 
the  top  with  nothing  but  an  empty  cage.  On  starting,  the  engine 
has  to  raise  not  only  the  weight  of  the  load  of  mineral,  but  also 
the  entire  weight  of  the  rope  hanging  down  the  shaft,  and  in  deep 
mines  with  large  cages,  this  weight  is  by  no  means  inconsiderable. 
In  proportion  as  the  full  cage  is  raised,  the  amount  of  dead 
weight  of  rope  to  be  lifted  becomes  less  and  less.  Eventually  the 
full  and  empty  cages  meet ;  the  two  portions  of  the  rope  then 
balance  each  other,  and  the  engine  has  simply  to  overcome  the 
action  of  gravity  upon  the  mineral;  later  on  the  rope  of  the 
•empty  cage  is  longer  than  that  of  the  full  one,  and  assists  the 
engine  in  doing  its  work.  At  last  when  the  load  is  Hearing  the  top, 
the  drum  is  feeling  the  full  weight  of  the  rope  of  the  empty  cage. 

Constancy  of  load  is  easily  obtainable  with  the  cylindrical  drum 
by  the  simple  expedient  of  adding  a  balance  rope — that  is  to  say, 
a  rope  hanging  down  the  shaft  with  one  end  attached  to  the 
bottom  of  each  cage.  Provided  that  this  rope  agrees  in  weight 
with  the  winding  rope,  the  counterpoising  is  perfect,  for  on  each 
side,  in  every  phase  of  the  ascent  or  descent,  there  is  always  the 
same  dead  weight  acting  upon  the  drum.  This  method  is  adopted 
at  Llanbradach  and  also  at  De  Beers  Mine.  The  balance  rope 
often,  but  not  invariably,  passes  round  a  pulley  at  the  bottom  of 
the  shaft. 

With  the  same  object  in  view  the  drum  is  made  spiral  or 
conical,  or  rather  of  a  combination  of  two  such  drums  united  by 
their  larger  bases.  The  rope  is  so  arranged  that  the  diameter  of 
the  coil  increases  as  the  act  of  winding  up  proceeds.  The  load  at 
the  bottom  of  the  pit  acts  upon  the  drum  shaft  with  a  small 
amount  of  leverage,  and  its  leverage  increases  as  the  weight  due 
to  the  rope  diminishes.  The  reverse  condition  of  affairs  exists 
with  the  descending  load :  it  has  a  large  leverage  while  there  is 
only  a  short  length  of  rope  hanging  down  the  shaft,  but  as  the 
weight  thrown  upon  the  drum  increases,  so  the  leverage 
•diminishes. 

Intermediate  between  the  conical  and  the  cylindrical  drum  is 
one  which  combines  the  two  systems ;  the  conical  end  is  used 
for  starting  the  load  from  the  bottom  and  the  main  part  of  the 
operation  is  performed  with  the  cylindrical  surface. 

When  a  flat  rope  is  used  instead  of  a  round  one,  it  is  convenient, 
for  the  sake  of  distinction,  to  speak  of  the  winding  cylinder 
as  a  reel  or  bobbin  (Figs.  436  and  437).*  It  is  provided  on 
both  sides  with  long  radial  arms,  which  serve  the  same  purpose 
-as  the  horns  or  flanges  in  the  case  of  the  drum ;  that  is  to  say, 
they  prevent  the  rope  from  slipping  off  sideways. 

*  Gallon,  Lectures  on  Mining,  vol.  ii.  plate  Ixi. 


394 


ORE  AND  STONE-MINING. 


The  flat  rope  coils  upon  itself,  and  as  the  winding  proceeds  the 
diameter  of  the  coil  increases,  if  the  cage  is  being  raised,  or 
decreases  if  the  cage  is  being  let  down.  In  this  way  there  is  a 
certain  compensating  action  similar  to  that  which  is  obtained 
with  a  spiral  drum — in  other  words,  at  the  moment  of  starting, 
when  the  load  is  at  the  bottom,  the  smallest  amount  of  leverage 
is  exerted  upon  the  driving  shaft  of  the  reel ;  whereas  at  the  end 
of  the  wind,  when  the  load  is  least,  it  is  exerting  the  greatest 
leverage. 

FIG.  436. 


FIG.  437. 


SCALE 


3  METRES 
13       14  FT. 


Pulley- Frames. — The  framework  at  the  top  of  the  shaft  for 
supporting  the  pulley  or  pulleys  is  known  by  different  names.  It 
is  sometimes  called  the  head-gear,  the  pit-head  frame,  or  poppet 
heads  (Cornwall).  It  may  be  constructed  of  timber,  iron  or  steel, 
and  metal  pulley-frames  are  usually  seen  nowadays  at  large  mines, 
where  winding  is  conducted  upon  an  extensive  scale  ;  at  small 
mines  and  also  during  sinking  operations  a  timber  head-gear  is 
common. 

A  kind  of  frame  often  used  is  shown  by  Figs.  438,  439,  440, 
from  which  it  will  be  seen  that  four  large  upright  posts  support 
cross-beams  A,  B,  C,  D,  upon  which  the  pulleys  rest.  The  frame  is 
suitably  stiffened  by  struts.  Its  principal  duty  is  to  resist  two  forces, 


HOISTING  OR  WINDING. 


395 


one  exerted  by  the  load  and  rope  hanging  down  the  shaft,  and  the 
other  by  the  rope  which  is  being  hauled  in  by  the  drum.     At  a 

FIG.  439. 


FIG.  438. 


moment  just  before  the  load  begins  to  move  the  two  forces  will  be 
equal,  and  the  direction  of  their  resultant  will  be  a  line  bisecting 
the  angle  between  the  two  parts  of  the  rope,  and  passing  through 

FIG.  440. 


the  centre  of  the  pulley.  Provision  therefore  should  be  made  for 
resisting  this  pull,  and  this  is  effected  by  stays,  such  as  are  shown 
in  Figs.  438  and  440,  which  represent  a  pulley-frame  used  fo 


396 


ORE  AND  STONE-MINING. 


sinking  a  shaft  some   200  yards  deep  at  Halkyn  Mine  in  Flint- 
shire.     The  backstay  may   be  placed  in  any  position   between 

FIG.  441. 


the    bisectrix    and   a  line   parallel   to   the   rope   going  to   the 
drum. 
During  the  sinking  at  Halkyn  only  one  bucket  was  used,  and 


HOISTING  OR  WINDING. 


397 


as  this  had  to  hang  in  the  middle  of  the  shaft  the  pulley  was 
placed  between  the  two  beams  B  and  C.  Now,  the  shaft  is  used 
for  winding  with  two  small  cages  and  there  are  two  pulleys,  one 
between  A  and  B,  the  other  between  C  and  D. 

Fig.  441  shows  the  head-gear  erected  at  the  perpendicular  "  Rock 
shaft"  of  De  Beers  Mine,*  whilst  Fig.  442  represents  the  arrange- 
ments at  the  Incline  shaft  of  the  same  mine. 

The  head-gear  at  both  shafts  is  made  of  wrought-iron  trellis 
work.  At  the  Rock  shaft  the  legs  and  stays  are  of  3  J-inch  angle- 
iron,  |  inch  thick.  The  lattice  bars  are  3  J  by  f  inch ;  the  total 
height  from  the  ground  to  the  centre  of  the  pulleys  is  6 1  feet. 

FIG.  442. 


Pulleys. — Winding  pulleys  have  to  be  placed  on  the  pit-head 
frame  in  order  to  change  the  direction  of  the  rope. 

Nowadays,  in  all  important  windings,  the  pulleys  are  made  from 
10  to  15,  and  even  20  feet  in  diameter,  in  order  to  subject  the  rope 
as  little  as  possible  to  sharp  bendings,  which  would  reduce  its  life. 

The  cast-iron  boss,  or  centre,  is  joined  by  wrought-iron  arms  to 
a  grooved  rim  also  made  of  cast  iron  (Fig.  443).  In  course  of 
time  steel  ropes  wear  away  the  rim,  and  to  lessen  this  source  of 
trouble,  the  part  in  which  the  rope  lies  may  be  chilled.  The 
groove  should  fit  the  rope;  for  if  it  is  too  wide,  the  rope  will 
rest  upon  a  small  part  of  its  circumference  and  be  liable  to  be 
squeezed. 

At  some  mines  pulleys  are  made  with  a  light  rim,  which  will 
not  last  for  more  than  a  year.  The  object  in  view  is  the  preven- 
tion of  wear  from  rubbing.  When  the  speed  of  the  engine  is 

*  Second  Annual  Report  of  De  Beers  Consolidated  Mines,  Limited,  for  the 
Year  ending  March  31,  i$go,  p.  16  and  plates  10  and  7. 


398  ORE  AND  STONE-MINING. 

slackening,  the  pulley,  in  virtue  of  its  momentum,  tends  to  travel 
faster  than  the  rope,  and  thereby  to  grind  its  surface.  A  dimi- 
nution in  the  weight  of  the  rim  lessens  the  momentum,  and 
therefore  reduces  the  rubbing  action.  The  advantage  gained  in 
this  way,  is  considered  sufficient  to  compensate  for  the  more 
frequent  changing  of  the  pulleys. 

2.  HOPES,  CHAINS,  AND    ATTACHMENTS.— Ropes. 
— Ropes  are  made  of  vegetable  fibre  of  some  kind,  or  of  iron  or 

FIG.  443- 


steel  wire.  The  vegetable  fibres  used  are  hemp  and  manilla, 
which  are  twisted  into  yarn ;  the  yarns  are  laid  together  so  as 
to  form  strands,  and  finally  the  strands  are  laid  together  to  form 
the  rope. 

For  winding  by  hand,  in  sinking  small  intermediate  shafts 
(winzes),  a  hemp-rope,  about  |  inch  in  diameter  and  made  up  of 
three  strands,  is  commonly  employed.  For  heavier  work,  either 
a  round  rope  of  larger  section  is  necessary,  or  a  flat  rope  formed 
by  sewing  together  several  round  ropes, 

Iron  is  very  little  employed  nowadays  for  making  wire  ropes 
its  place  has  been  taken  by  steel. 


HOISTING  OR  WINDING. 


399 


The  advantage  of  using  steel  as  compared  with  iron,  is  evident 
from  the  following  figures  :  * 


Us* 

§, 

3   • 

lls 

gas 

S.S8  . 

Kind  of  Wire. 

Tensile  str 
per  sq.  m 
kilogram 

Kind  of 
Rope. 

Total  useful  effect 
in  kilogrammetres. 

V 

-w.2  ° 

Eemarks. 

Iron  . 

60 

Cylindrical 

5,387,124,051 

5*5 

Kreuzer. 
0-817 

Crucible     ) 
Cast  Steel  J 

1  2O 

,, 

26,519,326,190 

22-3 

0-354 

j  ? 

35 

120 
1  80 

Tapering 

56,797,296,369 
69,898,974,017 

26-1 
20-8 

0-198 
0-238 

Kope  still 

in  use. 

FIG.  4430. 


It  must  be  remarked  that  the  data  concerning  the  last  rope 
are  incomplete,  as  it  was  still  in  use  when  the  paper  was  written. 

At  Pribram,f  where  winding  is  carried  on  in  perpendicular 
shafts,  one  of  which  has  attained  the  enormous  depth  of  3642 
feet,  the  ordinary  crucible  cast-steel,  with  a  tensile  strength  of 
120  kilos  per  sq.  mm.,  was  used  up  to  the  year  1885  ;  since  then 
they  have  employed  wire  of  "  patent  crucible  cast  steel "  or 
"  extra "  or  "  special  crucible  cast  steel,"  with  a  tensile  strength 
of  1 80  to  190  kilos  per  sq.  mm. ;  the  results  are  most  satisfactory, 
and  the  ropes,  after  having  been  in  use  for  two  and  a  half  years, 
showed  very  little  sign  of  wear,  and  not  a  single  broken  wire.  The 
former  ropes,  made  of  ordinary  cast  steel,  lasted  on  an  average 
only  26  months. 

Winding-ropes  are  usually  made  with  six  strands  and  a  central 
core  of  hemp,  each  strand  being  made  up  of 
seven  wires  (Fig.  443^).  The  core  is  sometimes 
made  of  wire ;  for  instance,  if  the  rope  has  to 
work  in  a  very  hot  shaft,  or  if  it  is  used  for 
haulage  purposes  with  clips  which  require  that 
the  diameter  should  remain  constant.  In  or- 
dinary ropes  the  "lay"  of  the  strand  is  like 
that  of  hemp  ropes ;  that  is  to  say,  the  reverse 
of  the  lay  of  the  rope  (Figs.  444  and  445). 
Lang  has  improved  the  method  of  manufacture  by  making  the 
lay  of  the  strand  the  same  as  the  lay  of  the  rope ;  the  wires 
are  less  sharply  bent,  and  present  a  longer  wearing  surface. 

*  Habermann,  "  Ueber  die  Drahtseilfabrikation  in  PHbram  mit  besonderer 
Riicksicht  auf  die  Drahtseile  fiir  die  Verticalf  orderung. "  Beilage  z.  Oest- 
Zeitschr.  f.  B.-  u.  H.-  Wesen,  1891,  p.  8. 

t  Habermann  "Anwendung  verjiingter  Forderseile  aus  gewohnlichem 
und  aus  Patent-  oder  Extra-Tiegelgussstahldraht  bei  den  grossen  Schacht- 
tiefen  des  Pfibramer  Bergbaues."  Oest.  Zeitschr.  f.  £.•  u.  If.-  Wesen, 
vol.  xxxviii.  1890,  pp.  403,  415,  432. 


400 


ORE  AND  STONE-MINING. 


FIGS.  444  and  445. 


FIGS.  446  and  447. 


The  result  is,  that  whilst  the  wires  of  an  ordinary  rope  wear 
quickly  on  the  crown  of  the  bend  and  break  (Fig.  445),  Lang's 
rope,  with  its  greater  wearing  surface,  has  a  much  longer  life. 
Figs.  446  and  447  are  taken  from  actual  examples  of  Lang's 
rope  before  and  after  use. 

Haggle's  patent  Protector  rope  has  a  special  covering  destined 

to  take  the  wear.  Each 
strand  has  a  wire 
wound  round  it  spir- 
ally, which  protects  it 
from  rubbing,  and 
therefore  a  more  flex- 
ible wire  can  be  used 
than  would  be  advis- 
able with  an  unpro- 
tected rope,  Whilst  an 
ordinary  rope  is  weak- 
ened by  the  wear  of 
its  wires,  the  strength 
of  the  protected  rope 
does  not  suffer  from 
the  gradual  thinning 
of  the  covering. 

Messrs.  Latch  and 
Batchelor  have  lately 
introduced  a  "flattened 
strand  "rope  (Figs.  448, 
449,  and  450).  The 
object  of  the  new 
method  of  construction 
is  to  obtain  an  outer 
surface  more  nearly 
cylindrical  than  that 
of  the  ordinary  rope 
(Fig.  443<0-  The 
strands  are  oval  in 
section,  and  this  form 
is  produced  by  "  lay- 
ing "  ordinary  wires 
round  a  flat  wire  or  a 
combination  of  wires.  It  is  evident  from  the  figures  that  the 
bearing  surface  of  the  rope  is  thus  increased,  or,  in  other  words, 
that  the  liability  of  any  individual  wire  to  wear  is  lessened.  It 
is  asserted  by  the  inventors  that  their  rope  has  150  per  cent, 
greater  wearing  surface  than  Lang's  or  ordinary  ropes. 

In  designing  the  "  locked  coil  wire  rope,"  now  made  by  Messrs. 
George  Elliot  &  Co.,  the  inventors  departed  entirely  from  the 
old  traditions  of  manufacture.  They  considered,  and  very  properly, 


FIG.  450. 


HOISTING  OR  WINDING. 


401 


FIG.  451. 


that  when  one  is  dealing  with  a  material  like  steel- wire,  which 
can  be  obtained  of  very  great  length,  it  is  quite  unnecessary  to 
copy  the  methods  suitable  for  the  short  fibres  of  hemp. 

These  ropes  are  made  of  wires  of  different  sections ;  some  of  the 
wires  are  V-shaped,  others  more  like  the  letter  S,  and  the  adjacent 
wires  fit  into  one  another  like  a  set  of  spoons,  the  concave  part 
of  one  wire  receiving  the  convex  part  of  the  next.  The  rope  is 
not  composed  of  a  series  of  strands,  but  of  a  series  of  concentric 
rings  of  shaped  wires,  and  the  separate  wires  form  long  spirals. 

By  consulting  Fig.  451,   which  represents  one  variety,  it  is 
evident  that  nearly  the  whole  of  the  section  of  the  rope  is  made 
up  of  useful  material.     There  are  scarcely  any  spaces   such   as 
exist   between   the   wires    and   the 
strands   of  an   ordinary   rope,    and 
consequently  for  any  given  section 
the  locked   coil   variety   of  rope   is 
stronger  than  a  strand  rope. 

It  is  very  flexible  and  has  a  smooth 
uniform  surface,  which  makes  it 
look  at  a  little  distance  like  a  solid 
bar  of  iron.  No  one  wire  of  the  outer  ring  is  more  exposed  to 
wear  than  the  other ;  consequently  there  is  not  the  danger  of 
having  broken  wires,  arising  from  the  top  of  the  crown  being 
rubbed  off  by  continued  use  (Fig.  445).  Another  advantage  is 
the  absence  of  any  tendency  to  turn,  whereas  the  ordinary  rope 
with  the  spiral  strands  twists  somewhat  when  passing  over  a 
pulley.  In  sinking  a  shaft  with  such  a  rope,  the  kibble  spins 
round  during  its  descent  and  ascent,  involving  a  risk  of  accident, 
which  is  best  avoided.  However,  strand  ropes  that  will  not  twist 
are  supplied  by  some  makers. 

The  disadvantage  of  the  locked  coil  rope  is  that  it  cannot  be 
spliced,  but  sockets  can  be  used  for  connecting  one  length  to 
another. 

Intermediate  in  character  between  the  ordinary  rope  and  the 
locked  coil  rope  is  the  variety  known  as  Laidler's  patent  "  Sector 
wire  rope."  Each  strand  is  cylindrical,  and  is  composed  of  several 
wires  in  the  form  of  sectors  of  a  circle,  and  the  strands  are  laid 
together  to  make  the  rope.  Fathom  for  fathom,  it  is  a  little 
heavier  than  Lang's  rope,  but  it  is  said  to  give  a  great  deal  of 
wear. 

Chains. — Chains  were  largely  used  in  ore-mining  at  one 
time.  They  have  the  advantage  that  they  will  coil  round  a 
small  drum,  and  the  further  advantage  that  they  will  stand  much 
rough  usage,  such  as  fell  to  their  lot  formerly  in  some  {of  the 
crooked  shafts  in  Cornwall.  But  there1  is  the  overwhelming  dis- 
advantage that  a  chain  is  no  stronger  than  its  weakest  link  ; 
a-nd  now  that  wire  ropes  have  come  into  use  in  mines,  winding 
with  the  chain  is  practically  a  thing  of  the  past. 

2  C 


4O2 


ORE  AND  STONE-MINING. 


Attachments. — It  is  important  to  study  the  modes  of  connect- 
ing the  rope  to  the  receptacle  by  which  the  mineral 
is  drawn  up.  In  sinking  by  hand  in  Cornwall,  FIG.  452. 
the  hemp  rope  is  attached  to  the  bucket  by  a  knot 
known  as  the  "  gooseneck,"  which  is  said  never  to 
slip,  and  which  is  easily  and  quickly  made;  but 
where  the  bucket  is  emptied  without  being  de- 
tached, this  latter  point  is  of  little  importance. 
In  Wales  and  the  Isle  of  Man  a  spring  hook 
(clevis)  is  preferred,  such  as  shown  in  Fig.  452, 
the  rope  being  put  through  an  eye  and  made  secure 
by  a  large  knot.  This  method  is  convenient  when 
it  is  necessary  to  detach  the  bucket,  and  move  it 
away  from  the  shaft  before  it  is  emptied.  A  third 
device  is  a  spiral  hook  which  will  not  allow  the  bucket  to  fall 

off  in  the  operations 

FIG.  453.  FIG.  455-  FIG.  456.    of  raising  and  lower_ 

ing,  whereas  it  can 
be  readily  taken  off 
by  the  workman. 

With  a  wire  rope 
it  is  necessary  to  form 
a  loop  of  some  kind, 
which  can  be  attached 
to  the  load  by  a  D- 
shaped  link  with  a 
screw  pin.  There  are 
several  means  of  ef- 
fecting this  purpose. 
The  ropes  sent  from 
the  makers  are  often 
supplied  with  an  eye 
spliced  in  (Fig.  453*), 
that  is  to  say,  the  end 
of  the  rope  is  turned 
round  an  eye  and 
then  spliced  back  so 
as  to  hold  it  firm.  As 
there  is  not  always 
a  competent  splicer 
at  mines,  methods  of 
attachment  have  to 
be  employed  which 
—  are  within  the  capa- 
FlG'  454-  city  of  an  ordinary 

smith.    Thus  the  end  of  the  rope  may  be  bent  back  over  an  eye 


*  Copied,  by  permission,  from  Messrs.  George  Cradock  &  Co.'s  figures. 


HOISTING  OR  WINDING. 


403 


and  held  in  position  by  three  clamps  (Figs.  454  and  455),*  or  a 
socket  may  be  riveted  on  (Fig.  456).* 

Figs.  457,  458  and  459  represent  a  socket  made  by  Messrs. 
George  Elliot  &  Co.  for  the  locked  coil  rope  and  for  ordinary  round 
wire  ropes.  A,  locked  coil  wire  rope ;  B,  socket ;  C,  hollow  conical 
plug ;  I),  wire  bound  or  "  served "  round  the  rope  ;  E,  ends  of 
the  wires  of  the  rope  turned  back  over  the  cone  ;  F,  wire  bound 
round  them.  After  the  end  of  the  rope  has  been  prepared  in 


FIG.  460.     FIG.  461. 


FIG.  457.    FIG.  458.    FIG.  459. 


SCALE 


2  FEET 
i METRE 


this  way  and  drawn  into  the  socket,  the  rings  G  G  G  are  driven 
down,  and  the  fastening  is  complete. 

Figs.  460  and  46 1  explain  the  "  capping,"  which  has  been 
adopted  at  some  collieries  near  Bristol,  since  the  failure  of  a 
riveted  socket.  A  A,  clamps  for  holding  the  rope,  each  with 
four  bolts;  B,  cast-iron  plate  with  a  groove  all  round  it  in 
which  the  rope  lies ;  C,  a  large  shackle  attached  to  the  iron  plate 
by  a  pin  E. 

A  description  of  the  method  of  splicing  ropes  will  be  found 

*  Copied,  by  permission,  from  Messrs.  George  Craddock  &  Co.  's  figures. 


404 


ORE  AND  STONE-MINING. 


in  the  catalogues  of  some  of  the  well-known  rope-makers,  and 
need  not  be  repeated  here. 

Splicing  is  not  always  adopted  for  joining  two  parts  of  a  wire 
rope;  sometimes  a  socket  is  attached  to  each  end,  and  the  two 
sockets  are  then  connected  by  a  D-link  with  a  screw  pin.  It 
should  be  remarked  that  it  is  often  at  or  near  the  socket  that 
the  rope  wears,  and  consequently  it  is  advisable  to  remove  the 
sockets  at  regular  intervals,  cut  off  a  piece  of  the  rope,  and 
replace  the  socket  where  the  rope  is  good  and  sound. 

I  have  hitherto  been  speaking  of  winding  ropes  of  uniform 
section,  but  tapering  ropes  have  advantages.  Let  us  take  the  case 
of  a  wire  rope  which  is  hanging  down  a  deep  pit.  The  part  of  the 
rope  at  the  bottom  of  the  shaft  has  simply  to  support  the  cage 
or  bucket  and  the  load  contained  therein,  whilst  the  part  at  the 
top  must  be  strong  enough  to  support  not  only  the  weight  of  the 
receptacle  and  its  load,  but  also  the  weight  of  the  rope  below  it. 
In  other  words,  greater  strength  is  required  at  one  end  of  the 
rope  than  at  the  other,  and  on  this  account  tapering  ropes  are 
sometimes  employed. 

The  advantage  of  employing  such  ropes  is  especially  felt  in 
the  case  of  very  deep  shafts,  such  as  those  of  the  famous  lead 
and  silver  mines  of  Pribram  already  alluded  to.  Three  of  the 
principal  shafts  have  the  following  depths : 


Kaiser  Franz  Josef  shaft 
Adalbert  shaft  .  * 
Maria 


looo  metres  or  3281  feet. 
1070         „         3510    „ 
1 1 10         „        3642    „ 


FIG.  462. 


The  taper  is  produced  by  using  successively  wires  of  smaller 
section,  and  not  by  reducing  their  number. 

3.  RECEPTACLES. — There  are  three  kinds  of  .receptacles 
in  which  the  load  is  raised  in  the  shaft :  (a)  Buckets  (kibbles), 
baskets  or  bags  which  are  swinging  loose  in  the 
shaft ;  (b)  buckets  or  boxes  (skips,  Cornwall) 
working  between  guides ;  (c)  cages  carrying  one 
or  more  waggons. 

(a)  The  buckets  are  made  of  wood,  sheet 
iron,  or  sheet  steel. 

Wooden  kibbles  are  made  of  staves  in  the 
same  way  as  a  barrel,  and  are  suitably  strength- 
ened with  bands  of  iron  in  order  to  resist  the 
wear.  A  petroleum  barrel  cut  down  at  one  end 
may  be  easily  converted  into  a  kibble. 

Various  forms  are  seen — viz.,  round,  elliptical, 
or  square,  and  the  sides  are  straight,  or  bulging 
in  the  middle.     Fig.  462  represents  a  common 
form  of  sheet-iron  kibble,  made  of  hammered 
plates   riveted  together  and  closed  at  the  bottom  by  a  circular 
plate  provided  with  a  ring.     4-t  the  top  is  the   so-called   bow, 


HOISTING  OR  WINDING.  405 

either  a  bar  of  round  iron  with  a  hook  at  each  end  and  bent 
so  as  to  form  a  loop  in  the  middle,  or  else  made  thicker  and 
provided  with  a  hole,  to  which  the  rope  or  chain  is  attached. 

In  perpendicular  shafts,  a  lining  of  planks  is  often  put  in 
around  the  winding  compartment,  so  that  the  kibble  may  glide 
up  and  down  smoothly,  without  risk  of  catching  against  the 
sides. 

In  inclined  shafts  the  "  foot  wall "  side  is  lined  with  boards 
(bed-planks)  resting  upon  cross  sleepers.  Hard  wood,  such  as  oak 
or  beech,  will  naturally  last  longer,  and  require  fewer  repairs 
than  deal.  In  the  Hartz,  poles  fixed  lengthwise  take  the  place 
of  boards,  which  are  customary  in  this  country. 

Other  receptacles  used  in  winding  are  baskets,  whence  comes 
the  name  corf(Korb,  German),  bags  made  of  hides  used  in  Mexico, 
small  wooden  platforms  suspended  by  chains  from  the  four  corners, 
and,  lastly,  nets,  which  are  employed  in  Roumania. 

A  word  must  be  said  about  the  actual  loading  and  emptying  of 
the  kibble ;  sometimes,  as  already  mentioned,  the  kibble  is  filled 
at  the  working- place  or  from  a  shoot  (pass,  Cornwall),  and  is  then 
conveyed  on  a  trolley  to  the  shaft,  where  it  is  hooked  on  to  the 
rope  and  drawn  up.  More  frequently  the  filler,  standing  in  an 
enlarged  part  of  the  level  (plat)  where  it  joins  the  shaft,  loads  the 
kibble  with  a  shovel ;  in  order  to  save  time,  two  kibbles  are 
often  provided,  one  being  filled  while  the  other  is  making  the 
journey  to  and  from  the  surface.  In  this  case  it  is  necessary  to 
have  some  kind  of  clevis,  which  will  enable  the  kibble  to  be  readily 
detached  from  the  winding  rope  and  quickly  and  securely  fastened 
on  again. 

On  the  arrival  of  the  kibble  at  the  surface,  the  lander  seizes 
an  eye  or  ring  at  the  bottom  (Fig  462)  by  a  pair  of  tongs  sus- 
pended to  a  chain,  and  then  gives  the  signal  for  the  rope  to  be 
lowered  slightly.  The  kibble  turns  over  because  it  is  suspended 
from  the  bottom,  and  its  contents  are  shot  out  into  a  tram- waggon 
placed  ready  to  receive  them.  During  the  operation  of  discharg- 
ing the  kibble,  the  mouth  of  the  shaft  should  be  covered  by  a 
hinged  door,  so  as  to  prevent  stones  from  falling  down  and 
injuring  the  filler  in  the  plat. 

The  inconveniences  of  this  method  of  winding  are  considerable, 
especially  in  inclined  and  crooked  shafts.  Rapid  hoisting  is  out 
of  the  question.  Power  is  wasted  in  overcoming  friction,  and 
there  is  great  wear  and  tear  of  the  bed-planks  and  casing  boards  ; 
and,  unless  constant  attention  is  paid  to  repairs,  holes  are  worn  in 
which  the  kibble  catches,  causing  the  rope  to  break.  The  fall  of  a 
kibble  and  its  contents  not  only  does  much  damage  to  the  shaft, 
but  is  also  a  source  of  danger  to  the  men.  In  some  old  shafts  the 
friction  must  have  been  enormous,  for  deep  grooves  have  been 
worn  in  hard  rock  by  the  constant  rubbing  of  the  chain. 

The  aerial  incline,  known  in  Scotland  as  the  "  Blondin,"  is  a 


406  OEE  AND  STONE-MINING. 

convenient  method  of  raising  stone  from  open  quarries,  when  it 
is  necessary  from  time  to  time  to  alter  the  point  at  which  load- 
ing takes  place. 

A  B  (Fig.  463  *)  is  a  strong  upright  post,  held  firmly  in  posi- 
tion by  guy  ropes,  of  which  only  one,  C  A,  is  shown.  A  D  is  a 
stout  wire  rope,  fixed  to  the  top  of  the  post,  and  anchored  at  D 
on  the  opposite  side  of  the  quarry.  It  constitutes  an  aerial  rail 
for  two  grooved  pulleys  contained  in  the  travelling  cradle  E. 
The  rope  F,  attached  to  the  cradle,  passes  over  the  large  pulley 
G,  and  thence  to  a  horizontal  winding-drum,  not  shown  in  the 
figure.  The  engine-house  is  at  the  very  edge  of  the  quany,  and 
is  so  placed  that  the  engine-man  can  look  down  to  the  bottom. 
The  cradle  E  will  run  down  from  A  to  D  by  its  own  weight,  and 
can  be  drawn  up  by  winding  the  rope  F  upon  its  drum.  A  loop 
attached  to  E  supports  the  large  pulley  H,  and  the  hoisting  rope 
I.  This  rope  passes  under  the  pulley  K,  over  the  pulley  H,  over 
a  pulley  immediately  by  the  side  of  G,  and  thence  to  a  drum 
precisely  like  that  of  F,  and  running  upon  the  same  shaft.  L  is 
a  rectangular  box,  like  the  body  of  a  waggon,  which  is  loaded 
with  stone  at  the  bottom  of  the  quarry,  and  hooked  on  to  the 
four  chains  hanging  from  K ;  it  is  then  drawn  up  arid  landed  on 
to  the  truck  M.  I  will  suppose  that  the  load  has  been  hooked  at 
the  point  N  in  the  bottom  of  the  quarry,  vertically  below  L  in  its 
present  position.  The  drum  of  I  is  thrown  into  gear  by  a  clutch 
and  the  rope  wound  up.  K  is  gradually  raised,  and  when  it  ap- 
proaches H,  the  drum  belonging  to  F  is  thrown  into  gear;  the  ropes 
F  and  I  are  now  wound  up  at  the  same  speed,  until  E  is  drawn 
close  up  to  A,  with  its  load  hanging  directly  over  M.  Winding 
is  stopped,  brakes  are  put  on,  and  the  drum  of  I  is  disengaged  by 
its  clutch.  By  slackening  the  brake  of  I,  while  that  of  F  is  kept 
tight,  the  load  can  be  lowered  on  to  M,  which  is  trammed  away 
as  required.  An  empty  box  is  hooked  on,  K  is  wound  up  a  little, 
till  it  approaches  H,  and  then,  throwing  the  drum  of  I  out  of 
gear,  the  engine-man  lets  both  ropes  run  out  under  the  control  of 
their  brakes.  When  E  has  reached  its  proper  position,  it  is 
stopped  by  tightening  the  brake  of  the  F  drum ;  K  then  descends 
vertically  till  L  has  reached  the  bottom  of  the  quarry. 

It  is  evident  that  by  properly  arresting  the  descent  of  E,  the  box 
can  be  lowered  so  as  to  pick  up  a  load  at  any  point  along  the  line 
O  P,  which  is  vertically  below  A  D.  If  after  a  time  it  becomes 
more  convenient  to  load  elsewhere,  the  anchorage  at  D  is  shifted 
accordingly. 

At  slate  quarries  in  North  Wales  and  Cornwall,  the  rope  F  is 
not  used,  and  E  is  stopped  by  a  clamp  fastened  at  any  desired 
point  of  the  rope  A  D.  The  arrangement  shown  in  Fig..  463 
introduced  many  years  ago  by  Mr.  Fyfe  at  granite  quarries  near 

*  For  the  sake  of  making  a  clear  diagram  on  a  small  page,  Fig.  463  is 
not  drawn  to  scale. 


HOISTING  OR  WINDING. 

FIG.  463. 


407 


4o8 


ORE  AND  STONE-MINING. 


Aberbeen,  is  better,  for  it  does  away  with  the  necessity  of 
sending  a  man  down  the  rope  to  adjust  the  clamp.  A  slightly 
different  plan  is  in  use  at  Easdale  slate  quarry  in  Argyllshire. 
The  travelling  cradle  carries  the  usual  hauling  rope  I,  but  in  place 
of  F  there  is  attached  to  it  an  endless  rope,  which  stretches 
across  the  quarry,  and  passes  over  suitable  pulleys.  So  long  as 
the  endless  rope  is  free  to  move,  the  cradle  will  run  from  A  to 
D,  but  when  the  banksman  stops  its  travel  by  a  screw  clamp, 
the  load  ascends  or  descends  vertically.  If  the  slope  of  the 
carrying  rope  fixed  across  the  quarry  is  too  small  to  allow  the 
cradle  E  to  run  of  itself,  an  endless  rope,  worked  by  a  drum,  is 
used  for  hauling  it  backwards  or  forwards  as  required. 

(b)  Guided  Buckets  or  Boxes. — When  winding  in  shafts  it  is 
best  to  employ  guides,  in  order  to  keep  the  receptacle  in  one  proper 
course,  and  prevent  it  from  touching  the  sides.  The  guides  may  be 
chains,  wire  ropes,  bars  of  wood  or  round  iron,  or,  lastly,  iron  or 
steel  rails. 

Chains  are  rarely  met  with ;  the  commonest  method  of  guiding  in 
perpendicular  shafts  is  to  hang  two  stout  wire  ropes  from  the  top 
to  the  bottom  of  the  pit,  and  to  provide  the  winding  receptacle  with 
eyes  which  pass  over  them.  They  are  kept  taut  by  weights  or  screws. 
Wire-rope  guides  may  be  used  even  in  the  case  of  a  kibble ;  a 
cross-bar  with  two  eyes  is  attached  near  the  end  of  the  winding 
rope  ;  though  the  kibble  remains  loose,  it  is  so  close  to  the  cross- 
bar that  it  can  swing  but  little.  By  fitting  wire-rope  guides  of  this 
kind  to  perpendicular  shafts  originally  worked  with  the  ordinary 
loose  kibble,  winding  can  be  carried  on 
with  greater  speed  and  safety,  whilst  the 
cost  of  making  the  alteration  is  com- 
paratively small.  There  is  the  further 
advantage  that  the  shaft  when  provided 
with  guides  becomes  available  for  raising 
and  lowering  the  men. 

Some  years  ago  Mr.  William  Galloway* 
introduced  an  ingenious  method  of  apply- 
ing these  wire-rope  guides  to  a  shaft  in 
the  course  of  sinking.  He  provides  two 
wire-rope  guides  coiled  upon  two  drums 
which  are  worked  by  a  steam  crane, 
either  separately  or  together.  The  guide 
ropes  (a  a,  Fig.  464)  pass  over  two  pulleys 
at  the  top  of  the  shaft,  parallel  to  the 
winding  pulley,  and  are  attached  to  a 
platform,  which  serves  as  a  walling  stage,  and  is  raised  and 
lowered  as  required.  A  hole  in  the  middle  affords  a 
for  the  bucket  (kibble,  bowk,  tioppef). 

*  "  Sinking  Appliances  at  Llanbradach,"  Trans.  /South  Wales  Inst.  of 
.,  vol.  xvi.,  1888,  p.  113. 


FIG.  464. 


HOISTING  OR  WINDING. 


409 


FlG'  465. 


As  the  shaft  is  deepened,  the  guide  ropes  are  paid  out  from 
time  to  time,  and  in  this  manner  it  is  only  at  the  very  bottom 
that  the  bucket  is  swinging  loose.  The  guiding  apparatus  consists 
of  a  cross-bar  having  a  round  hole  in  the  centre  c,  through  which 
the  winding  rope  passes.  It  has  two  legs  with  holes,  b  b,  at  top 
and  bottom  which  receive  the  guides.  This  rider  descends  as 
the  bucket  is  lowered,  but  when  the  legs  meet  with  the  walling 
stage  their  motion  is  arrested  ;  the  kibble,  however,  can  proceed 
further  because  the  winding  rope  passes  down  through  the  central 
hole  c. 

After  passing  below  the  stage  the  kibble  is  unguided,  but  the 
distance  it  has  to  travel  is  rarely  more  than  15  or  20  yards.  Before 
starting  on  its  upward  journey,  the  kibble 
is  brought  properly  into  line  with  the  rope 
and  steadied,  and  on  arriving  at  the  stage, 
an  india-rubber  buffer,  carried  by  an  iron 
plate  at  the  bottom  of  the  rope,  lifts  up  the 
rider  ;  the  remainder  of  the  ascent  is  per- 
formed without  fear  of  the  kibble  swinging 
or  catching. 

Mr.  Galloway's  latest  walling  stage  has 
two  floors,  10  feet  6  inches  apart  ;  the  lower 
one  is  a  circular  platform  of  timber  fixed 
to  a  frame  of  angle-iron  d1  d?  (Figs.  465  and 
466),  and  made  to  fit  the  inside  of  the  shaft 
as  closely  as  possible. 

The  part  h  is  hinged,  and  can  be  raised  by 
means  of  the  chain,  when  passing  the  cross- 
beams (bunions)  which  support  a  ventilating 
pipe.  The  upper  floor  of  the  stage  is  similar 
to  the  lower  one,  except  that  it  is  somewhat 
smaller  in  diameter,  and  is  not  made  to 
cover  the  hinged  segment  below.  The  two 
floors  are  held  apart  by  four  corner  pieces 
of  angle-iron,  to  which  are  attached  four  plates  of  sheet  iron, 
forming  together  a  frustrum  of  a  pyramid,  5  feet  6  inches  square 
at  the  top,  and  6  feet  6  inches  square  at  the  bottom.  The  object 
of  these  plates  is  to  prevent  men  who  are  standing  upon  the 
lower  stage  from  falling  into  the  central  opening,  and  at  the  same 
time  the  upper  floor  constitutes  a  protecting  roof  over  their 
heads. 

Men  can  climb  from  the  lower  to  the  upper  platform  by  means 
of  the  ladder  m  which  passes  through  a  small  man-hole  in  the 
iron  covering  plates. 

The  two  guide  ropes  which  carry  the  stage  are  shown  by 
letters  n  n'. 

This  double  stage  is  decidedly  safer  than  the  single  platform 
originally  employed  by  Mr.  Galloway. 


-pIG 


410  ORE  AND  STONE-MINING. 

Although  primarily  designed  for  sinking  coal-pits,  and  most 
frequently  applied  for  this  purpose,  this  method  of  guiding  was  used 
with  marked  success  in  sinking  a  shaft  at  New  Minera  lead  and 
zinc  mine  near  Wrexham  ;  it  was  found  that  the  great  advantage 
of  being  able  to  wind  with  safety  at  a  higher  speed,  fully  repaid 
the  expense  of  putting  in  the  guides. 

In  the  Northwich  mines,  rock-salt  is  brought  up  in  wooden 
buckets  guided  much  in  the  same  way,  except  that  round  iron 
bars  are  employed  instead  of  ropes.  Each  length  of  rod  has  a 
socket  at  one  end  and  a  projecting  pin  at  the  other ;  the  pin  of 
one  rod  fits  into  the  socket  of  the  next  and  is  fastened  by  a, 
key  driven  through  a  slot.  These  guides  are  chosen  in  the  special 
case  of  salt  because  they  suffer  less  from  rusting  than  those  made 
of  wire  ropes,  owing  to  the  absence  of  interstices  in  which  saline 
water  would  collect  and  corrode  the  iron. 

We  next  come  to  the  box  of  rectangular  or  circular  section 
(skip),  made  of  sheet  iron  or  sheet  steel.  It  usually  has  a  sloping 
bottom,  and  is  provided  with  a  hinged  door  for  discharging  its 
contents ;  in  some  instances  it  is  emptied  by  being  turned  over 
automatically  on  reaching  the  top  of  the  shaft.  The  skip  may  be 
used  in  perpendicular,  inclined,  or  crooked  shafts.  The  guides  or 
conductors  are  most  commonly  rectangular  bars  of  wood,  bolted  to 
the  end-pieces  of  the  shaft  and  to  the  "  dividings  "  in  the  manner 
shown  by  Fig.  257. 

If  the  shaft  is  perpendicular  the  skip  may  be  guided  by  two 
U-shaped  shoes  of  iron,  which  clasp  the  three  sides  of  the  con- 
ductor. If  it  is  inclined  the  skip  runs  upon  four  wheels,  as  shown 
by  Fig.  467.  In  an  inclined  shaft  the  conductors  sometimes  have 
rails,  upon  which  the  wheels  of  the  skip  run,  in  others  the  timber 
is  not  protected  in  any  way.  Some  of  the  skips  in  Cornwall  are 
made  to  hold  as  much  as  a  ton  and  a  half  of  tin-bearing  rock. 

When  winding  is  going  on  from  any  particular  level,  a  stop, 
such  as  a  strong  bar  of  iron,  is  put  across  the  shaft  to  arrest  the 
skip ;  the  miner,  standing  in  the  plat,  shovels  the  mineral  into  it, 
and  gives  the  signal  to  have  it  drawn  up  as  soon  as  it  is  filled. 

A  better  plan  is  to  adopt  the  arrangement  explained  in  Fig,  467, 
which  will  easily  be  understood.  B  is  a  strong  plate  working  on 
a  pivot  which  is  put  down  to  stop  the  skip  ;  C  is  a  pivoted  hood 
turned  over  the  mouth  of  the  skip  so  as  to  prevent  stones  from 
falling  into  the  shaft,  and  when  this  is  in  its  place  the  workman 
raises  the  door  of  a  large  bin  or  hopper,  and  allows  part  of  its 
contents  to  run  out.  The  hopper  has  been  filled  by  tipping 
waggons  from  the  line  of  rails  in  the  level  above. 

On  reaching  the  surface  a  hinged  sloping  door  is  turned  over 
the  shaft,  and  the  skip  is  lowered  a  little  until  it  rests  upon  it ;  the 
workman  (lander)  then  knocks  up  the  bolt  retaining  the  door  of 
the  skip,  and  the  contents  fall  out  into  the  tram-waggon  placed 
to  receive  them.  The  lander  replaces  the  bolt,  the  skip  is  raised 


HOISTING  OR  WINDING. 


411 


slightly,  the  door  pulled  back,  and  the  skip  lowered  once  more 
into  the  shaft. 

The  skip  is  sometimes  tilted  completely  over  instead  of  being 
emptied  through  a  hinged  door ;  this  arrangement  is  in  use  in 
some  German  mines,  where  the  skip  is  made  of  wood  and  is  guided 
on  each  side  by^two  pins  or  rollers  running  between  two  con- 

FIG.  467. 


ductors.  On  reaching  the  surface,  the  two  lower  pins  are  sup- 
ported and  act  as  pivots,  while  the  upper  ones  pass  through 
openings  in  the  front  guides ;  the  skip  turns  upon  the  lower  pins, 
is  tipped  over,  and  so  emptied. 

Some  very  rapid  work  is  done  at  De  Beers  mine*  with  a  self- 
discharging  skip,  which  shows  that  this  method  of  hoisting  must 
not  be  despised,  even  by  those  who  are  accustomed  to  the  wind- 
ing of  large  quantities  of  coal  from  well  equipped  pits. 

*  Second  Annual  Report  of  De  Beers  Consolidated  Mines,  Limited,  for  the 
year  ended  jsst  March  1890,  p.  14,  plate  8. 


412 


ORE  AND  STONE-MINING. 


The  skip  (Figs.  468  and  469)  runs  upon  four  flanged  wheels,  and 
the  two  upper  or  front  wheels  are  half  the  width  or  tread  of  the 
two  back  or  lower  ones.  The  winding  rope  is  attached  to  two 
chains,  which  are  fixed  to  the  cross-bar  of  a  loop  or  stirrup  which 
can  turn  upon  pins  fixed  to  the  sides.  The  skip  runs  upon  steel 

FIG.  468. 


SCALE 


2  METRES 


rails  (46-!-  Ibs.  to  the  yard)  laid  upon  what  may  be  called  con- 
ductors or  longitudinal  sleepers.  At  the  bottom  of  the  shaft 
there  is  an  iron  shoot,  without  any  door,  leading  to  the  skip. 
During  the  descent  of  the  skip,  four  end-tipping  waggons  are 
brought  into  position  round  the  shoot,  the  catches  of  the  flap-doors 
are  loosened,  and  the  doors  held  closed  by  two  labourers.  As  soon 
as  it  is  seen  to  pass,  the  trucks  are  tipped,  and  the  signal  is  given 

FIG.  469. 


to  wind  up.  The  skips  are  filled  so  quickly  at  the  bottom,  that 
the  man  at  the  top  sometimes  receives  this  signal  before  he  has 
completely  stopped  his  engine. 

When  the  skip  B  (Fig.  442),  ascending  the  incline  shaft  A, 
reaches  the  point  C,  its  rear  wheels  are  caught  up  by  a  special 
broad  road  D,  the  gauge  of  which  is  wide  enough  to  let  the  front 
wheels  pass  through.  Whilst  the  front  wheels  are  travelling  on 
the  rails  E,  the  rear  wheels  continue  to  mount,  and  consequently 
the  skip  turns  over  and  discharges  its  contents  into  the  bin  F. 


HOISTING  OR  WINDING. 


H  is  a  waggon  waiting  to  be  filled,  and  G  a  counterpoise  to  the 
discharge  door. 

On  lowering  the  rope,  the  skip  falls  back  into  its  original  position 
and  descends  the  shaft.  The  inclination  of  the  shaft  is  56°  20' 
from  the  horizontal.  The  skip-ways  are  5  feet  wide  and  4^  feet 
high,  and  the  gauge  of  the  railway  is  3  feet  1 1  inches.  There  are 
two  tracks,  which  converge  at  the  bottom  into  one,  so  that  both 
skips  can  be  filled  from  the  same  shoot.  A  skip  holds  64  cubic 
feet,  or  4  loads,  weighing  in  all  2  tons  17  cwt.,  or  2903  kilos. 

The  best  single  day's  work,  in  two  shifts  of  10  to  icj  hours 
each,  was  6222  loads,  or  4444  statute  tons.  The  depth  of  the 


FIG.  470. 


FIG.  471, 


FIG.  472. 


6  Fee.* 


shaft  is  840  feet  along  the  incline,  or  700  vertical;  the  speed  in 
the  shaft  is  840  feet  in  30  seconds,  and  the  time  occupied  in 
tipping  and  reversing  about  6  seconds.  This  rate  of  working 
has  been  carried  on  for  an  hour  at  a  time,  5  skips  being  discharged 
every  three  minutes — that  is  to  say,  285  statute  tons  per  hour. 

Fig.  470  shows  the  details  of  double-lipped  mouth  of  the  shoot 
at  the  bottom  of  the  great  bin  (F,  Fig.  442),  which  receives  the 
blue  ground  brought  up  from  underground.  The  door  A  is  con- 
trolled by  the  cam  worked  by  the  lever  B,  and  the  door  C  is  upon 
the  same  axis  as  the  lever  D.  The  discharge  is  thus  easily 
regulated,  and  waggons  can  be  filled  with  great  rapidity. 

The  arrangement  for  inclines  shown  in  Figs.  471  and  472 
differs  slightly  from  that  adopted  at  De  Beers.  A  waggon  A, 


TT  "NT  T  T-  v-,  J 


414 


ORE  AND  STONE-MINING. 


running  upon  four  wheels  B,  is  drawn  up  by  the  bow  F,  and  the 
rope  J.     The  bow  is  attached  to  the  axles  of  the  hind  wheels, 

FIG.  473. 


and   in  front  it  carries  the  door  I  of  the  waggon.     K   repre- 
sents the  railway  at  the  top  of  the  incline,  and  P  an  additional 


HOISTING  OR  WINDING. 


FIG.  474. 


outer  line  of  rails  at  a  steeper  angle.  When  the  waggon  in 
its  upward  course  reaches  the  point  L,  the  rails  P  pick  up  the 
small  outer  wheels  C  on  the  rear  axle.  These  travel  up  at  the 
steeper  angle  whilst  the  front  wheels  follow  the  rails  K.  Conse- 
quently, the  waggon  is  tilted,  and,  as  the  front  end  or  door  is 
attached  to  the  bow,  the  contents  are  shot  out.  The  stud  G  keeps 
the  waggon  in  position  if  it  is 
drawn  up  too  far.  On  lowering 
the  rope,  the  waggon  rights 
itself  and  descends  properly. 

Automatic  tipping,  or  dump- 
ing, is  also  possible  in  per- 
pendicular shafts.  The  "Kock" 
shaft  at  De  Beers  is  20  feet  by 
6  feet,  divided  into  four  com- 
partments which  are  each  4 
feet  4  inches  by  6  feet  within 
the  timber :  one  for  the  pumps 
and  ladder-way,  another  for  a 
cage,  and  two  for  the  skips. 

Figs. 441, 473  and  474*  repre- 
sent the  arrangements  adopted. 
A  is  the  skip,  a  box  of  rect- 
angular section,  5  feet  by  3 
feet  at  the  top  and  6  feet 
deep;  B,  frame  which  clasps 
the  wooden  guide  on  three 
sides ;  C,  hinge  by  which  the 
skip  is  attached  to  the  frame  ; 
D,  hooked  bar  which  catches 
upon  the  pin  E ;  F,  guide  which 
presses  the  little  roller  D1  and 
so  unhooks  the  catch ;  G,  roller 
which  travels  along  the  guide- 
rails  H  for  causing  the  tipping ; 
I,  nose  upon  the  skip,  which  is 
temporarily  caught  upon  the 
roller  J  during  the  tipping ;  K, 
inclined  guide  for  the  roller 

G;  L,  crosspiece  attached  firmly  to  the  side-frames  B,  with  a 
hole  M,  through  which  slides  the  strong  square  bar  N;  0, 
toothed  segments  forming  the  safety  catches ;  P,  plate  attached 
by  chains  to  the  axles  of  the  catches ;  Q,  Ormerod's  detaching 
link  ;  R,  shackle  which  is  released ;  S,  rope-socket ;  T,  wire-rope  ; 
U  (Figs.  441  and  475),  bell-mouthed  cylinder  for  causing  the 


*  From  drawings  kindly  supplied  by  the  makers,  The  Grange  Iron  Co., 
Limited,  of  Durham. 


416  ORE  AND  STONE-MINING. 

detaching  link  to  come  into  action;  V,  chain-pulley  of  safety 
catch ;  W,  strong  spring,  like  a  huge  watch-spring. 

After  this  explanation  of  the  parts,  the  manner  in  which  the 
tipping  or  dumping  is  performed  will  be  easily  understood.  As 
long  as  the  hook  D  is  horizontal,  the  skip  is  prevented  from 
falling  forwards,  but  on  arriving  at  the  top  of  the  shaft,  its 
roller  D1  is  drawn  up  against  the  guide  F  and  the  catch  is  released. 
By  this  time  the  roller  G  has  reached  the  guide-rails  H,  and 
whilst  the  frame  B  follows  a  vertical  path  upwards,  the  box 
itself,  held  back  by  G,  turns  upon  the  hinge  C  until  it  assumes 
the  position  shown  by  the  dotted  lines,  with  the  nose  I  resting 
upon  the  roller  J.  As  the  frame  ascends  still  further,  the  roller 
G  is  drawn  up  along  the  inclined  guide  K,  the  bottom  of  the 
box  is  tilted  up,  and  its  contents  are  discharged  into  the  bin 
or  hopper.  On  lowering  the  rope  the  frame  descends,  the  skip 
drops  back  into  its  original  normal  position  and  is  clamped 
automatically  by  the  bar  D. 

Whilst  the  plate  P  is  held   up   against  the   cross-bar   L,  the 

chains  of  the  safety  catches  O  are  drawn  tight,  and  the  teeth  are 

held  clear  of  the  wooden  guides   in   the   position   shown.     The 

moment   the  rope  breaks,  the  chains  become  slack,  the  springs 

are  then  free  to  uncoil  slightly  and  they  force 

FIG.  475.  the  teeth  into  the  wooden  guides. 

If,  instead  of  a  breakage  of  the  rope,  there 
is  an  overwind,  the  detaching  link  Q  is  drawn 
into  the  bell-mouthed  cylinder  U  (Fig.  475), 
the  lower  part  of  the  link  is  squeezed,  as  it  is 
too  wide  to  pass  through,  and  is  thereby 
caused  to  throw  out  projecting  shoulders 
which  rest  upon  the  top  of  U  and  hold  up 
the  skip.  By  the  same  action  the  shackle 
K  is  set  free  and  goes  with  the  rope  over 
^^^^^__M,  the  pulley. 

A  self -discharging  skip,  suitable  for  vertical, 

inclined,  or  crooked  shafts,  is  that  of  Messrs  Kitto,  Paul  and 
Nancarrow,  used  at  Frongoch  mine  in  Cardiganshire.*  (Figs.  476 
to  480). 

The  skip  is  the  usual  box  A,  made  of  sheet  iron  or  sheet  steel, 
with  four  wheels  B  B,  running  on  the  vertical  wooden  conductors, 
H  H,  and  prevented  from  leaving  them  by  the  back  guide  D 
(Figs.  477  and  479)  at  or  near  the  bottom. 

The  bow  or  loop  E,  instead  of  being  attached  to  the  top  of  the 
skip,  reaches  down,  and  takes  hold  of  the  axles  of  the  bottom 
wheels ;  in  its  usual  position  (Fig.  478)  it  rests  against  the  axles  of 
the  upper  wheels,  and  holds  the  skip  upright. 

*  C.  Le  Neve  Foster,  "  Some  Mining  Notes  in  1887,"  Trans.  Min.  Assoc. 
and  Inst.  of  Cornwall,  vol.  ii.  p.  140. 


HOISTING  OR  WINDING. 


At  the  surface,  each  of  the  two  ordinary  conductors  bends 
round  and  terminates  in  a  horizontal  piece,  as  shown  in  Fig.  480, 
whilst  a  front  guide  H'  is  added  on  each  side. 

When  the  skip  comes  up,  these  front  guides  press  upon  the 
top  wheels,  and  turn  them  on  to  the  flat  ends  of  the  ordinary 
conductors.  Deep  grooves  cut  in  the  conductors  at  I  enable  the 
back  guide  D  to  pass  through,  and  as  the  rope  continues  to  be  drawn 
up  the  bottom  end  of  the  skip  is  raised  and  its  contents  are  tipped  or 
"  dumped  "  into  a  large  bin  or  pass,  from  which  the  ore  can  be 
drawn  away  at  pleasure.  If  the  engine-man  does  not  stop  quite 
soon  enough,  the  skip  is  simply  drawn  up  a  little  way,  resting 
upon  the  front  guide,  and  the  stop  or  stud  F  prevents  it  from 
assuming  a  wrong  position. 


FIG.  476.      FIG.  478. 


FIG.  480. 


FIG.  477.       FIG.  479- 


Scale  ^ 

In..l2      P        ?       ?      3 


*       5  Fee* 


As  soon  as  the  engine-man  begins  to  lower,  the  top  wheels 
fall  upon  the  flat  ends  of  the  conductors,  and,  turning  upon  them, 
the  tail  end  of  the  skip  drops,  the  back  guide  passes  through 
the  slot  I,  and  the  skip,  resuming  its  upright  position,  descends 
the  shaft. 

The  great  advantage  of  this  and  other  self -tipping  arrange- 
ments is  the  saving  of  time  and  labour.  The  time  occupied  in 
lowering  an  ordinary  skip  on  to  the  shaft-door,  in  knocking  up  a 
bolt  so  as  to  discharge  its  contents,  in  closing  it  again,  and  in 
raising  the  skip  so  that  the  shaft-door  may  be  thrown  back,  is 
all  saved,  and  the  services  of  the  lander  are  dispensed  with. 

(c)  Cage. — The  system  of  winding  adopted  almost  universally 
at  collieries  is  that  of  using  cages ;  this  method  is  likewise  very 
general  in  mining  seams  of  ore,  and  is  not  uncommon  in  the  case 
of  veins  and  masses. 

2  D 


418 


ORE  AND  STONE-MINING. 


The  cage,  as  its  name  implies,  is  a  more  or  less  open  receptacle, 
which  receives  the  waggon  used  for  underground  transport,  and 
conveys  it  to  the  surface. 

Figs.  481  and  482  represent  the  light  and  simple  cage  used  in 
the  mines  on  the  Comstock  lode :  *  it  is  a  mere  timber  platform 
5  feet  by  4  feet,  resting  on  iron  bars  p  and  supported  by  iron  rods 
on  each  side.  It  is  provided  with  a  sheet-iron  bonnet  to  protect 
the  men  inside  from  anything  falling  down  the  shaft,  and  also 
with  safety  catches,  which  come  into  play  if  the  rope  breaks. 

FIG.  482. 


The  hand  levers  k  k  at  the  ends  of  the  cage,  raise  up  blocks 
which  keep  the  tram-waggon  in  its  place  during  the  ascent  or 
descent ;  g  g  are  the  guides  for  the  ends  of  the  cross-bar  b  •  c,  the  bar 
working  the  teeth  t  t  by  levers ;  /  shoe  or  ear  embracing  the  guide- 
rod,  or  conductor,  in  the  shaft ;  r,  the  lifting  bar ;  s,  a  strong 
spring  which  comes  into  operation  if  the  rope  breaks. 

This  kind  of  cage  looks  somewhat  bare  to  European  eyes,  and 
it  is  usual,  on  this  side  of  the  Atlantic,  to  make  the  sides  less  open 
than  shown  in  Fig.  482. 

The  dimensions  of  the  cage  are  limited  by  the  size  Sf  the  shaft; 
but  where  it  is  desired  to  raise  a  larger  quantity  of  mineral  than 

*  J.  H.  Hague,  "  Mining  Industry,"  Eep.  U.  S.  Geol.  Expl.  o/  4oth 
Parallel,  vol.  iii.,  plate  vii.,  p.  119. 


HOISTING  OK  WINDING.  419 

•can  be  contained  in  one  waggon,  or  in  two  placed  side  by  side,  the 
carrying  capacity  may  be  increased  by  constructing  the  cage  with 
two  or  more  platforms,  technically  called  decks. 

As  a  rule,  the  full  waggon  is  drawn  out  of  the  cage  at  the  top 
of  the  shaft,  and  is  trammed  to  some  convenient  place  where  it  is 
tipped ;  of  late  years  the  ingenuity  of  American  inventors  has  led 
them  to  introduce  methods  of  tipping  the  waggon  automatically 
on  reaching  the  surface,  without  its  leaving  the  cage,  in  order  to 
save  time  in  winding.  Russell  and  Parson's  automatic  dump- 
ing cage,  said  to  be  doing  good  work  in  the  United  States,  has 
its  platform  movable  upon  an  axle  underneath,  which  allows  it  to 
be  tilted  on  one  side  or  the  other.  The  cage  has  the  usual  shoes  at 
the  top  and  bottom,  which  cover  5^  inches  of  the  wooden  guides 
or  conductors ;  the  tilting  platform  has  its  own  two  separate 
shoes,  which  clasp  only  2\  inches  of  the  guides.  Whilst  the  cage 
is  in  the  shaft,  the  platform  is  held  in  a  horizontal  position  by  its 
shoes  running  upon  the  guides.  At  the  surface  the  wooden  con- 
ductors are  cut  away  for  a  depth  of  2|-  inches,  so  that,  although 
the  cage  itself  is  guided,  the  small  shoes  are  free  to  move  side- 
ways and  permit  the  tilting,  when  the  platform  touches  a  properly 
arranged  stop.  The  flap-door  of  the  waggon  is  released  automati- 
cally at  the  same  time,  and  the  mineral  is  shot  out  into  a  large 
bin  at  the  pit-top. 

4.  OTHER  APPLIANCES— Keps.— On  arriving  at  the 
surface  the  cage  is  usually  lifted  a  little  higher  than  the  landing 
platform,  and  supports  of  some  kind  (heps)  are  brought  under- 
neath it,  so  as  to  hold  it  up  while  the  full  waggon  is  drawn  off 
and  an  empty  waggon  pushed  on.  The  cage  is  then  slightly 
raised,  the  supports  (heps)  are  drawn  back  by  a  lever,  and  the 
descent  begins. 

Several  methods  of  simplifying  the  work  have  been  devised, 
and  among  them  is  that  of  Messrs.  Haniel  and  Lueg,*  which  has 
been  found  to  act  satisfactorily  at  the  well-known  Mansfeld 
copper  mines. 

The  kep  a,  which  is  made  of  steel  (Figs.  483  to  485),  has  an  in- 
clined face  5,  and  is  provided  with  two  slots,  one  horizontal  and  the 
other  d  inclined.  The  former  acts  as  a  guide  to  the  block  e, 
which  is  loose  upon  the  axle  f\  f  is  supported  by  the  bearing  g. 
The  pin  i,  surrounded  by  a  steel  roller  h,  can  slide  in  the  slot 
d ;  it  connects  the  two  levers  k,  one  on  each  side  of  the  kep 
«,  which  are  keyed  to  the  axley*.  These  are  kept  in  a  horizontal 
position  by  a  lever  m  provided  with  a  spring  catch.  The  steel 
shoes  1 1,  attached  to  the  bottom  of  the  frame  of  the  cage,  will, 
if  desired,  rest  upon  the  inclined  faces  b  b  of  the  keps.  As  long 
as  the  lever  m  is  held  in  the  position  shown  in  Fig.  483,  the  keps 
cannot  open  under  the  pressure  of  the  load,  because  the  pin  i 
prevents  any  motion  in  a  horizontal  direction. 

*  The  explanation  and  figures  are  borrowed  from  their  description. 


420 


ORE  AND  STONE-MINING. 


When  the  lever  m  is  being  drawn  back,  as  shown  by  Fig.  484, 
the  pin  i  with  its  roller  h  is  forced  up  the  slot  and  the  keps  slide 
back  on  the  bed-plate  of  the  bearing  g,  until  the  cage  has  room 
enough  to  pass ;  when  it  has  gone  down,  the  keps  are  returned  to 

their  original  position 

FIG.  483.  (Fig.  483)  by  moving 

the  lever  m  forwards. 
The  ascending  cage 
opens  the  keps  by 
itself,  for  the  shoes 
1 1  turn  them  upwards 
(Fig.  485),  the  lower 
part  of  the  slot  d 
being  concentric  to 
the  spindle  /.  As 
soon  as  the  cage  has 
passed,  they  fall  back 
into  their  normal  posi- 
tion (Fig.  483),  and 
the  cage  is  lowered  so 
as  to  rest  upon  them. 
The  advantage 
claimed  for  keps  of 
this  kind  are :  Eco- 
nomy of  steam  and 
saving  of  time,  besides 
the  increased  duration 
of  the  rope,  which  no 
longer  has  to  under- 
go the  strain  of  start- 
ing the  cage  upwards 
before  it  begins  its 
downward  journey. 

Signals. — It  is  ne- 
cessary to  have  some 
means  of  communi- 
cation between  the  various  on-setting  places  and  the  top  of  the 
shaft,  so  that  the  man  at  the  bottom  (on-setter,  hooker-on) 
may  be  able  to  inform  the  man  at  the  top  (banksman,  lander,  or 
engine-man),  when  he  is  ready  for  the  cage,  skip,  or  kibble  to 
be  drawn  up. 

In  shallow  workings  shouting  is  sufficient ;  when  the  pit  becomes 
deeper  a  speaking-tube  is  sometimes  put  in,  but  the  commonest 
method  of  signalling  is  by  a  cord  made  of  seven  galvanised  wires, 
and  varying  in  diameter  from  J  to  f  inch.  The  object  of  the 
zinc  coating  on  the  wire  is  of  course  to  prevent  or  delay 
rusting,  which  would  otherwise  go  on  rapidly  in  the  damp 
atmosphere  of  many  shafts. 


HOISTING  OR  WINDING.  421 

The  cord  is  carried  round  curves  and  corners  by  means  of 
cranks  similar  to  those  used  for  house-bells,  only  larger  and 
stronger,  and  when  it  is  pulled  by  a  lever  at  the  bottom,  it 
moves  a  hammer  which  strikes  a  bell  at  the  surface.  Instead  of  a 
bell,. a  loose  plate  of  iron  is  sometimes  used,  which  makes  a  very 
audible  signal ;  the  number  of  strokes  indicates  what  is  required. 
The  usual  code  is  as  follows : 

1  stroke  means  "  Stop." 

2  strokes  mean  "Wind  up." 

3  „          „       "Lower." 

Yarious  signals  can  be  arranged  to  indicate  when  men  are  to  be 
•drawn  up  in  place  of  the  ordinary  load  of  mineral ;  and  sometimes 
a  visible  signal  is  combined  with  an  audible  one,  a  hand  upon  a  dial 
recording  the  number  of  times  the  bell  has  been  sounded.  When 
persons  are  raised  and  lowered,  there  must  also  be  means  of 
signalling  from  the  surface  to  the  on-setting  places  ;  the  object 
is  to  assure  the  men  at  the  bottom  that  their  signal  has  been 
correctly  received  and  understood. 

Electricity  can  also  be  called  to  the  aid  of  the  miner,  and  electric 
bells  are  common.  Telephones  *  of  various  descriptions  are  some- 
times used,  but  for  the  ordinary  purposes  of  winding,  the  simple 
signal  given  by  a  bell  is  quite  sufficient. 

In  addition  to  the  signal  for  starting  and  stopping,  there  is 
an  indicator  which  shows  the  engine-man  the  exact  position  of 
the  load  in  the  shaft. 

The  indicator  may  be  a  dial  with  a  hand,  worked  by  gearing 
connected  with  the  crank-shaft  of  the  winding-engine  \  the 
various  stopping  places  are  denoted  in  the  same  way  as  the  hours 
on  the  face  of  a  clock,  the  gearing  being  arranged  so  that  the 
hand  does  not  travel  more  than  the  entire  circumference  during 
the  longest  journey  of  the  load. 

Another  form  of  indicator  is  an  upright  standard,  6  or  8  feet  in 
height,  with  a  slot,  in  which  a  pointer  moves  up  and  down.  It  is 
worked  by  a  cord,  or  a  steel  band  connected  to  the  crank-shaft. 
The  standard  has  horizontal  lines,  numbered  according  to  the 
depths  of  the  different  stopping-places  ;  the  gearing  is  contrived 
&o  that  when  the  finger  points  to  one  of  these  lines,  the  cage  is  at 
the  corresponding  stopping-place. 

The  arrival  of  the  load  near  the  surface  may  be  brought  to 
the  engine-man's  notice  in  several  ways :  by  a  mark  on  the  rope, 
by  the  pointer  on  the  indicator,  and  by  some  audible  signal, 
worked  automatically  by  the  winding-engine.  A  travelling 
hammer  may  be  carried  along  by  a  screw,  connected  by  gearing 

*  The  first  time  the  telephone  was  used  for  1  ransmitting  speech  from 
underground  workings  of  a  mine  was  in  September  1877,  when  Mr.  Arthur 
Le  Neve  Foster  made  some  experiments  at  West  Wheal  Eliza,  in  Corn- 
wall. 


422 


ORE  AND  STONE-MINING. 


with  the  crank-shaft,  and  eventually  brought  up  against  a  bell ';. 
it  works  in  the  same  manner  as  the  device  upon  typewriters 
which  warns  the  operator  that  he  is  coming  to  the  end  of  a  line. 
Instead  of  striking  a  bell,  the  traveller  may  open  a  cock  and  start 
a  steam  whistle. 

5.  SAFETY  APPLIANCES  —  Overwinding, — In  rapid 
winding  with  large  drums,  a  slight  inadvertence  on  the  part 
of  the  engine-man  may  cause  the  load  to  be  drawn  up  against 
the  pulley,  and  this  is  what  is  commonly  known  as  over-winding. 
In  the  case  of  a  drum  18  feet  in  diameter,  a  single  revolution 
raises  the  rope  56^  feet;  therefore,  if  even  half  a  revolution  is 
allowed  beyond  the  proper  number,  an  accident  will  ensue,  unless 
the  pulley  frame  gives  a  margin  of  nearly  30  feet. 

There  are  various  contrivances  for  preventing  disasters  of  this 


FIG.  486. 


FIG.  487. 


kind ;  one  method  consists  in  interposing  between  the  rope  and 
the  cage  a  special  appliance,  called  a  detaching  hook,  which  will- 
sever  the  connection  between  them,  allow  the  former  to  be 
wound  up,  and  at  the  same  time  hold  up  the  latter  safely  without 
damage  to  the  load  or  persons  inside. 

Some  well-known  detaching  hooks  are  those  of  King  and 
Humble,  Walker,  and  Ormerod  (Fig.  475). 

King  and  Humble's  consists  of  an  outer  framework  of  two 
cheeks  or  sides,  containing  two  inner  plates  which  can  move  about  a 
central  bolt  b  (Fig.  486).  Each  plate  has  a  wing  a,  projecting, 
beyond  the  framework.  When  in  use  the  two  plates  are  pre- 
vented from  coming  apart  by  a  small  pin  or  rivet,  c. 

If  the  cage  attached  to  e  is  wound  beyond  a  certain  height, 
the  detaching  hook  is  drawn  into  a  round  hole  in  a  strong 
iron  plate  (Fig.  487),  and  when  the  projecting  wings,  a  a, 
strike  against  this  plate,  they  are  forced  to  move  inwards,  the 


HOISTING  OR  WINDING. 


423 


rivet  is  cut,  the  shackle  d  at  the  end  of  the  rope  is  set  free,  and 
two  catches ff  are  thrown  out;  these  drop  upon  the  plate  and 
hold  the  cage  firmly  suspended. 

Walker's  detaching  and    suspending   hook   is  like  a   pair    of 
tongs,  which  hold  the  shackle  at  the  end  of  the  rope ;  the  legs 
of  the  tongs  are  bent  out,  and  if  they  are  brought  together  the 
tongs  open. 

FIG.  489. 

FIG.  488. 


In  Figs.  488,  489  and  490,  L  is  the  end  of  the  winding  rope, 
and  A  the  shackle  attached  to  it  by  the  pin  P.  D  D  are  the 
two  jaws  of  the  tongs,  and  F  F  are  projecting  hooks.  E  is  the 
centre  pin  about  which  the  jaws  can  move,  and  H  an  annular 
clamp  which  prevents  the  jaws  from  opening,  as  long  as  it  is 
kept  up  by  the  two  supporting  pins  I  I.  The  cage  or  skip  is 
hung  on  to  the  link  B,  and  the  weight  of  the  load  acting  upon 
the  two  legs  of  the  tongs  tends  to  bring  them  together  and  open 
the  jaws  D  D, 

When  winding  is  going  on  properly,  the  jaws  are  kept  together 


424 


ORE  AND  STONE-MINING. 


FIG.  490. 


by  the  clamp,  and  the  load  remains  firmly  attached  to  the  rope ; 
but  if  it  is  raised  too  high  the  detaching  hook  enters  the  strong 
ring  C,  through  which  it  can  pass  freely  until  the  flanges  K  K  of 
the  clamp  H  strike  against  it.  The  pins  I  I  are  sheared  off  and 

the  clamp  drops  ;  but  as  soon 
as  the  hooks  F  F  have  passed 
through  the  ring,  the  jaws 
D  D  are  drawn  open  by  the 
weight  of  the  load,  the  shackle 
is  thus  released  and  the 
hooks  catch  on  the  top  of 
the  ring  C.  As  an  'addi- 
tional precaution  there  is  a 
projecting  rim  at  O,  to  catch 
the  hooks  if  by  some  chance 
they  should  fail  to  act  at  the 
top. 

Stopping  Gear. — The  dis- 
engaging appliances  just  de- 
scribed are  designed  with  a 
view  of  correcting  the  effects 
of  an  overwind,  by  preventing 
the  ascending  cage  from  being 
dashed  against  the  pulley, 
arid  then  possibly  falling 
down  the  shaft.  But  they  in 
no  way  protect  the  descend- 
ing cage  from  bumping  on 
the  bottom ;  even  if  they 
did,  the  old  motto  still  holds 
good  that  "  prevention  is 
better  than  cure,"  especially 
as  detaching  hooks  have  been 
known  to  fail. 

Engineers  have  therefore 
been  anxious  to  obtain  some 
means  of  automatically  stop- 
ping the  cage  before  it  is 
raised  too  far,  and  many 
appliances  for  this  purpose 
have  been  invented. 

Three  which  were  exhibited  at  the  Paris  Exhibition  of  1889 
deserve  special  mention,  as  they  are  in  regular  use  at  large  and 
important  mines — viz.,  the  automatic  speed-checkers  and  stopping- 
gears  of  Reumaux,  Yilliers,  and  Wery.*  M.  Reumaux  lays  down 

*  Pamphlets  issued  by  the  Mining  Companies  at  the  Exhibition,  and 
Bevue  Universelle  des  Mines  et  de  la  Mttallurgie.  3®  Serie,  vol.  xix.,  1892 
pp.  949-956,  and  plates. 


HOISTING  OR  WINDING.  425 

the  principle  that  too  much  confidence  must  not  be  placed  in  an 
appliance  which  is  only  occasionally  called  into  action  ;  and  his  self- 
acting  speed-checker  conies  into  play  at  every  wind.  When  the 
cage  in  its  ascent  passes  a  point  30  m.  below  the  surface,  a  tappet 
upon  the  revolving  indicator  lifts  a  valve,  and  so  puts  one  end  of  a 
piston  valve  into  communication  with  the  atmosphere ;  as  steam 
or  compressed  air  is  pressing  upon  the  other  end,  the  valve 
moves  and  shuts  off  steam  from  the  engine  almost  completely. 
The  same  release  of  pressure  causes  another  valve  to  rise  and  let 
steam  into  the  cylinder  working  the  brake.  If  the  engine-man, 
after  turning  on  steam  again,  is  again  inattentive  and  allows  the 
cage  to  be  drawn  up  2  feet  above  the  landing,  a  second  tappet  upon 
the  indicator  once  more  causes  the  steam  to  be  shut  off;  and  a 
third  tappet,  by  opening  an  exhaust  passage,  makes  another  valve 
drop  and  turn  steam  on  to  the  cylinder  controlling  the  brake. 
M.  Reuinaux's  appliance  is  attached  to  all  the  winding  machines 
used  at  the  extensive  Lens  collieries,  whether  they  are  worked 
by  steam  or  compressed  air. 

Villiers'  apparatus  is  somewhat  complicated,  and  cannot  be 
properly  understood  without  a  figure.  Suffice  it  to  say  that  a 
nut  travelling  upon  a  screw  sets  gearing  in  motion  and  so 
actuates  a  friction  clutch  ;  this  brings  into  play  a  regulator  which 
opens  a  valve  and  lets  out  the  compressed  air  from  under  a  piston 
holding  up  a  weight.  The  weight  in  dropping  shuts  off  steam 
and  puts  on  the  brake.  A  second  part  of  the  apparatus,  working 
in  a  different  manner,  produces  like  effects ;  and,  lastly,  if  the  cage 
is  wound  up  a  certain  distance  above  the  landing,  it  strikes  a 
catch  which  releases  another  counterpoise,  the  descent  of  which 
also  causes  the  brake  to  act. 

With  Wery's  contrivance  the  connection  between  the  winding 
drum  and  the  checking  apparatus  is  again  effected  by  gearing 
and  levers  instead  of  fluid  pressure.  When  the  cage  has  reached 
a  certain  point  near  the  surface,  a  nut  travelling  upon  a 
screw  lifts  a  rod  carrying  a  pawl,  which  rests  upon  the  teeth 
of  a  wheel  turning  round  by  clockwork.  If  the  pawl  rises  more 
quickly  than  the  wheel  revolves,  it  lifts  it,  and  by  means  of 
levers  brings  the  steam-brake  into  action ;  the  speed  of  winding 
is  thus  diminished.  The  clockwork  is  so  regulated  that  the  brake 
is  not  made  to  act  unless  the  speed  is  excessive.  To  prevent 
danger  from  a  slow  overwind,  a  second  rod  acts  in  any  case  and 
turns  steam  on  to  the  brake  cylinder  if  the  cage  is  drawn  up  too 
high. 

Bertram*  and  Cobboldf  have  invented  automatic  stopping 
appliances  which  depend  upon  the  action  of  a  ball  governor, 

*  "  On  Overwinding  and  its  Prevention,"  Trans.  Fed.  Inst.  M.E.,  vol.  i., 
1890,  p.  55. 

f  "A  Patent  Apparatus,  Indicator  and  Valves  for  the  Prevention  of 
Overwinding  at  Mines." — Ibid.,  p.  61. 


426  ORE  AND  STONE-MINING. 

connected  by  gearing  with  the  main  driving  shaft  of  the  winding 
drum. 

Paschke  and  Kastner's  apparatus,  used  at  many  mines  in  the 
Freiberg  district,  is  spoken  of  favourably.  It  automatically 
shuts  off  steam  and  puts  on  the  brake,  not  only  when  the  cage  is 
being  drawn  up  too  high,  but  also  when  the  speed  is  excessive. 

Safety  Catches. — Much  ingenuity  has  been  displayed  by 
various  inventors  during  the  last  fifty  years,  with  the  object 
of  providing  some  form  of  catch  which  will  come  into  play  if  the 
rope  breaks,  grip  the  guides  or  conductors,  and  prevent  the  cage 
or  skip  from  falling  down  the  shaft. 

Many  of  them  are  actuated  by  a  spring,  and  one  form  has 
already  been  figured  in  describing  the  cage  used  on  the  Comstock 
lode  (Figs.  481  and  482). 

While  the  load  is  hanging  from  the  rope,  the  spring  s  s  is 
drawn  into  the  position  shown  by  the  dotted  lines  by  the  lifting 
bar  r,  the  eye  of  which  is  figured  in  its  two  positions.  The  bar 
c  is  drawn  up  at  the  same  time,  and  the  teeth  t  t  are  held  apart 
and  kept  clear  of  the  guide.  If  the  rope  breaks,  the  spring 
forces  down  the  bar  b  and  with  it  c  ;  the  teeth  jam  into  the 
wooden  conductor,  and  the  cage  is  arrested  and  held  firmly. 

The  safety  catch  used  for  the  De  Beers  skip  (Fig.  473) 
likewise  depends  upon  the  action  of  springs. 

An  objection  often  urged  against  safety  catches  is  that  they 
occasionally  come  into  play  when  not  wanted,  and  that  owing  to 
rust  and  disuse  they  get  out  of  order,  and  sometimes  fail  to 
act  at  the  proper  moment ;  for  these  reasons  they  are  less  popular 
on  this  side  of  the  Channel  than  on  the  Continent.  Many 
engineers,  rather  than  trust  to  contrivances  which  may  possibly 
fail  under  the  conditions  met  with  in  mines,  are  more  inclined  to 
put  their  faith  in  the  following  precautions : 

1.  Insuring  an  excellent  quality  of  rope,  by  going  to  a  maker  of 

good  repute  and  paying  a  fair  price. 

2.  Frequent  minute  examination  of  the  rope. 

3.  Testing  p;eces  of  the  rope  at  regular  intervals. 

4.  Protection  of  the  rope  from   the  action  of   the  atmosphere  or 

acidulous  water  in  the  mine  by  a  suitable  grease. 

5.  Cutting  off  the  end  of  the  rope  where  it  is  attached  to  the  cage 

and  re-making  the  attachment  at  regular  intervals. 

6.  Discarding   the  rope   after   it   has   been  in  use  a  certain  fixed 

time,  even  if  it  is  apparently  sound  as  far  as  outward  exam- 
ination can  show. 

The  same  feeling  seems  to  have  existed  among  the  members  of  the 
Royal  Commission  upon  Accidents  in  Mines,*  for  they  say,  "  We 
have,  however,  examined  several  varieties  of  the  safety  cages  in 

*  Final  Report  of  Her  Majesty's   Commissioners  appointed  to  inquire  into 
Accidents  in  Mines,  p.  109.     London,  1886. 


HOISTING  OR  WINDING  427 

use,  as  well  as  those  exhibited  at  successive  Internationa]  Exhibi- 
tions, and  we  have  considered  a  large  number  recently  described 
and  figured  in  an  elaborate  paper  by  Herr  Selbach,*  and  we  are 
unable  to  come  to  the  conclusion  that  any  one  of  them  is  a  trust- 
worthy safeguard  against  accidents."  This  opinion  does  not  settle 
the  question ;  for,  on  the  other  hand,  I  may  refer  to  the  con- 
clusions which  Menzel  f  draws  from  the  study  of  carefully  pre- 
pared official  statistics.  Though  far  from  asserting  that  existing 
safety  catches  are  perfect,  he  shows  that  on  the  whole  they  did 
useful  work  during  the  seven  years  1884-1890  in  the  coal  and  ore 
mines  of  Saxony,  and  he  considers  that  they  should  be  applied  to 
all  cages  used  for  winding  men. 

Springs. — The  rope  suffers  the  greatest  strain  at  the  com- 
mencement of  the  ascent  of  the  cage.  There  is  always  a  little  slack 
rope,  which  is  taken  up  as  the  winding  begins,  and  this  leads  to  the 
danger  of  a  sudden  strain  being  put  upon  the  rope  every  time  that 
it  begins  to  lift  the  cage,  especially  in  cases  where  winding  is  being 
carried  on  rapidly.  In  order  to  spare  the  rope  from  a  shock  of 
this  kind  and  cause  it  to  take  the  weight  gradually,  a  steel  or 
india-rubber  spring  may  be  interposed  between  the  cage  and  the 
rope,  arranged  in  such  a  fashion  that  the  first  action  of  the  pull 
is  merely  to  compress  it;  finally,  when  the  compression  has 
reached  a  certain  stage  the  cage  will  be  lifted.  The  bearings  of 
winding  pulleys  are  sometimes  supported  by  springs  with  a 
similar  object  in  view. 

Testing  Ropes. — The  Commentry  Fourchambault  Mining 
Company  keep  a  useful  record  of  the  state  of  their  winding  ropes 
by  testing  them  at  regular  intervals.  Once  in  every  six  months 
a  piece  of  rope  about  9  feet  long  is  cut  off  and  sent  to  a  powerful 
testing  machine,  called  the  antheximeter,  capable  of  breaking  a 
new  wire  rope  more  than  2  inches  in  diameter.  The  machine 
registers  upon  paper  not  only  the  force  required  to  break  the  rope, 
but  also  its  elongation  previous  to  rupture.  By  comparing  the 
results  obtained  in  this  way,  the  gradual  deterioration  of  the  rope 
from  wear  can  be  followed  with  great  precision.:}: 

In  the  mines  of  the  Dortmund  district,  no  winding-rope  can  be 
used  for  raising  and  lowering  men  until  it  has  been  carefully 
tested  in  a  manner  prescribed  by  the  Government  authorities.  A 
piece  of  the  rope  one  metre  in  length  is  cut  off,  and  the  tensile 
strength  and  the  flexibility  of  each  wire  are  determined,  with 
the  exception  of  wires  forming  cores. 

Pneumatic  Hoisting. — The  most   novel  hoisting  apparatus 

*  Zeitschr.  fur  das  B.-  H.-  und  /&-  Wesen,  vol.  xxviii.  1880.  B.  Abhartd- 
lungen,  p.  I. 

t  "Die  in  den  Jahren  1884-1890,  beim  sachsischen  Bergbau  vorge- 
kommenen  Briiche  von  Forderseilen,  Schurzketten  und  dergleichen."— 
Jalirb.f.  d.  B.-  u.  H.- Wesen  i.K.  Sachsen,  1891,  p.  39. 

£  Comptes  Bendus  Mensuels,  Soc.  Ind.  Min.  1891,  p.  257. 


OF  THE 

UNIVERSITY 


428  ORE  AND  STONE-MINING. 

is  that  of  M.  Blanchet,  which  was  regularly  at  work  in  the 
Hottinguer  shaft  at  Epinac  in  France  for  some  years.  M. 
Blanchet  fixed  in  the  shaft  a  large  pipe  with  a  piston,  from  which 
was  suspended  a  cage  carrying  waggons.  By  exhausting  the  air 
above  the  piston  the  load  was  gradually  forced  up  by  the  atmo- 
spheric pressure  below  it.  The  Hottinguer  shaft  is  660  yards 
deep,  and  the  pipe  was  5  feet  3  inches  in  diameter,  made  up  of 
a  succession  of  cylinders  of  sheet-iron  about  T\  inch  thick  and 
4  feet  4  inches  high,  joined  by  flanges  and  bolts.  The  485  rings 
composing  the  long  pipe  weighed  altogether  418  statue  tons.  The 
cage  had  nine  decks,  and  arrangements  were  made  for  unloading 
three  at  a  time ;  each  waggon  held  half  a  ton,  so  that  the  total 
useful  load  was  4^  tons.  The  speed  of  hoisting  was  20  feet  per 
second.  If  two  hoisting  pipes  are  connected,  the  dead  weights 
may  be  made  to  balance  each  other,  and  the  power  required  is 
simply  that  which  is  necessary  to  overcome  the  weight  of  the 
useful  load.  All  the  men  preferred  the  pneumatic  hoist  to  the 
ordinary  cage  for  descending  and  ascending  the  mine,  and  were 
regularly  lowered  and  raised  by  it.  The  advantages  claimed  by 
M.  Blanchet  for  this  system  are — (i)  the  possibility  of  hoisting 
from  depths  at  which  rope- winding  would  no  longer  be  practicable  ; 
(2)  getting  rid  of  the  costly  ropes  and  dangers  connected  with 
rope-winding;  (3)  better  utilisation  of  the  engine  power;  (4) 
improvement  of  the  ventilation  and  diminution  of  the  amount  of 
fire-damp.  At  the  present  time  Blanchet 's  apparatus  is  no  longer 
employed,  but  the  disuse  of  the  pneumatic  method  is  in  no  way 
due  to  any  difficulty  in  making  it  work  satisfactorily.* 

*  Nougarede,  "Etude  historique    sur  le  puits  Hottinguer  des  Mines 
d'Epinac,"  Bull.  Soc.  2nd.  Min.     3e  Serie,  vol.  vii.,  1893,  p.  563. 


(     429     ) 


CHAPTER  IX. 
DRAINAGE. 

Surface  drainage — Dams — Drainage  tunnels — Siphons — Raising  water  by 
winding  machinery — Pumps  worked  by  engines  at  the  surface — 
Rittinger  pump— Counterbalances — Bochkoltz's  regenerator — Rossig- 
neux's  contrivance — Catches — Pumps  worked  by  engines  placed 
below  ground — "  Duty  " — "  Slip  "  —  Co-operative  pumping. 

THE  mineral  having  been  raised  to  the  surface,  the  task  of  the 
miner  might  appear  to  be  at  an  end ;  but  this  is  not  the  case,  for 
it  is  further  necessary  that  he  should  keep  his  mine  free  from 
water  and  foul  air.  These  two  indispensable  operations  of  drain- 
ing and  ventilating  require  special  appliances,  which  often  add 
considerably  to  the  general  cost  of  mining. 

Surface  Water. — As  far  as  possible  the  miner  should  endeavour 
to  prevent  the  entry  of  water  both  at  the  surface  and  under- 
ground, and  so  escape  the  unnecessary  expense  of  pumping  it  up. 
In  some  instances  a  good  deal  can  be  done  in  this  direction  ;  for  it 
has  been  abundantly  proved,  in  many  cases,  that  the  bulk  of  the 
water  with  which  the  miner  is  burdened  is  merely  the  result  of 
the  percolation  of  the  rain  falling  in  the  district.  The  effect 
even  of  a  prolonged  rainfall  is  not  usually  felt  at  once,  for  it 
takes  time  for  the  water  to  find  its  way  through  minute  cracks 
and  crevices  in  the  ground  and  reach  the  workings.  In  lime- 
stone districts,  however,  the  rain  may  find  large  channels  eaten 
out  by  atmospheric  agencies,  and  affect  mines  at  a  depth  of  a 
couple  of  hundred  yards  within  twenty-four  hours  after  it  has 
fallen. 

It  often  happens  that  the  mineral  was  quarried  near  the  surface 
before  underground  mining  was  resorted  to,  and  in  that  case  there 
is  always  the  danger  of  the  old  open  pits  forming  a  sink,  so  to 
say,  which  will  collect  water  from  the  neighbourhood  and  let  a 
considerable  quantity  percolate  into  the  workings.  To  avoid 
such  an  objectionable  state  of  things,  the  surface  must  be  drained  ; 
special  care  is  imperative  where  the  ground  is  cracked  by  sub- 
sidences, and  the  neighbouring  streams  should  be  examined  and 
the  water  carried  along  in  launders  or  other  safer  channels,  if 
their  beds  cannot  be  made  stanch  by  filling  the  fissures  with 
concrete. 


43° 


ORE  AND  STONE-MINING. 


When  working  under  the  sea  or  a  river,  a  rich  lode  must  not 
tempt  the  miner  to  carry  on  his  work  too  far.  At  Wheal  Cock, 
near  St.  Just  in  Cornwall,  the  miners  working  in  some  overhand 
stopes  actually  bored  more  than  one  hole  through  to  the  sea- 
bottom.  They  were  well  aware  of  the  proximity  of  the  ocean, 
for  they  could  hear  the  boulders  crashing  against  each  other  in 
stormy  weather,  and  they  had  wooden  plugs  ready,  which  they 
drove  into  the  holes  when  they  actually  tapped  sea  water.  But 
it  was  a  dangerous  experiment,  and  though  in  this  case  the  rocks 
are  so  hard  and  compact  that  the  amount  of  percolation  is  small, 
a  narrow  wall  only  four  feet  thick  between  the  sea  and  the 
workings  cannot  be  left  without  fear  of  trouble  and  danger  from 
water  above. 

Dams. — In  addition  to  preventing  the  access  of  water  from 
the  surface,  it  is  advisable  to  cut  off  underground  inflows  as  far 
as  practicable.  In  the  chapter  upon  supporting  ground,  imperme- 
able linings  of  shafts  and  levels  have  been  described,  and  where  water 
can  be  shut  out  by  tubbing  or  by  coffering,  the  mine-owner  is 
saved  the  constant  expense  of  pumping;  indeed,  he  is  sometimes 
thus  enabled  to  work  deposits  which  he  would  not  be  able  to 
reach  if  he  had  to  fight  against  the  enormous  streams  issuing 
from  certain  strata.  Water  from  adjacent  abandoned  workings 
is  shut  out  by  dams — that  is  to  say,  artificial  stoppings — placed 
in  levels  or  shafts.  They  may  be  made  of  timber,  brickwork, 
masonry  or  concrete,  and,  when  intended  for  temporary  purposes, 
of  iron. 

In  erecting  a  dam  the  first  consideration  is  the  choice  of  a 
suitable  place,  for  it  is  useless  to  take  the  trouble  to  put  in  a 
stanch  stopping  unless  the  ground  is  firm  enough  to  support  it, 

and  free  enough  from  cracks  to 
prevent  the  water  behind  it  from 
finding  its  way  round  to  the 
front. 

If  the  ground  is  thoroughly 
strong,  a  dam  may  be  put  in  by 
cutting  a  recess  in  the  sides  of 
the  level,  as  represented  by 
Fig.  491,*  and  stopping  the 
water  back  by  a  wall  made  of 
horizontal  balks  of  timber.  Oak 
is  usually  chosen  for  the  purpose. 
Before  the  timber  is  put  in,  the 
rock  is  very  carefully  dressed  until  the  surface  is  perfectly 
smooth,  and  ready  to  receive  a  similar  surface  of  wood.  Each 
balk  is  wedged  up  against  the  side  just  in  the  same  way  as  a 
wedging  curb,  and  the  joints  between  the  separate  balks  are 
caulked. 

*  Gallon,  Lectures  on  Mining,  vol.  ii.,  plate  Ixxvi. 


DRAINAGE. 


43 1 


For  heavier  pressures  the  spherical  dam  is  available;  it  is 
constructed  of  wooden  logs  placed  longitudinally  and  wedged  up 
very  tightly.  A  wooden  dam  of  this  kind  has  the  advantage  that 
it  will  yield  a  little  if  there  are  movements  of  the  ground,  whereas 
a  dam  constructed  of  bricks  might  become  cracked  and  leak  so 
badly  as  to  be  almost  useless;  the  wooden  dam  is  also  more 
easily  repaired.  Oak,  pine,  and  fir  are  all  employed  for 
making  dams ;  the  two  latter  are  sometimes  preferred  to  the 
former,  because  they  are  more  easily  wedged.  The  following 
account  of  a  spherical  dam  is  based  upon  a  description  written  by 
Gatzschmann  *  (Figs.  492  to  495). 

FIG.  492. 


FIG.  493. 


A  nail  is  fixed  upon  a  cross-piece  in  the  middle  of  the  level,  about 
23  feet  (7  m.)  from  the  proposed  outer  face  of  the  dam,  and  the  sides 
of  the  level  are  trimmed  smooth  with  the  greatest  care  along  planes 
which  would  intersect  in  this  point  as  a  centre.  Pieces  of  timber 
are  cut  in  the  form  of  truncated  pyramids,  the  four  faces  of  which 
converge  to  a  centre  agreeing  with  that  chosen  underground; 
they  are  fitted  together  at  the  surface,  with  the  horizontal 
joints  arranged  along  the  lines  of  the  same  great  circles  of  the 
sphere  and  the  vertical  joints  alternating.  When  the  logs  have 
been  duly  fitted,  the  work  of  putting  them  in  is  begun.  Tarred 
canvas  is  placed  upon  the  floor  of  the  level  and  the  first  row  of 

*  Jahrbuchfur  den  Berg-  und  Hutten-  Mann  auf  das  Jalir  1841^  Freiberg. 
Combes,  Traite  del 'Exploitation  des  Mines.  Paris,  1884,  vol.  ii.,  page  721, 
and  plates. 


432 


ORE  AND  STONE-MINING. 


pieces  laid  down ;  the  last  piece  acts  as  a  keystone  and  is  driven 
in  with  a  sledge.  One  of  the  pieces  of  the  second  layer  has  a 
hole  bored  through  it  so  as  to  let  off  any  water  during  the  progress 
of  the  work.  When  the  middle  of  the  dam  is  reached,  a  flanged  cast- 
iron  pipe  is  put  in  as  a  man-hole,  and  the  other  rows  are  built  up  to 
the  roof,  which  has  been  covered  with  tarred  canvas  :  a  hole  is  bored 
through  one  of  the  pieces  of  the  uppermost  row  but  one  and  fur- 
nished with  a  bent  pipe,  which  serves  to  carry  off  the  air  at  the  top 
when  the  dam  is  finally  closed.  The  joints  between  the  logs  are 
made  watertight  by  driving  in  wedges  around  them  obliquely  ;  the 
first  wedges  are  of  pine,  the  next  are  of  hard  wood,  and  the  final 
set  are  of  iron.  A  coating  of  cement,  made  of  cart-grease,  tar 

FIG.  494. 


495.  FIG. 


and  slacked  lime,  completes  the  outer  face  of  the  dam.  The 
miners  then  close  the  water-hole  with  a  plug  made  of  beech,  and 
after  retiring  through  the  man-hole,  draw  into  it  a  huge  wooden 
stopper.  The  water  is  allowed  to  rise,  and  in  due  course  some 
passes  out  by  the  air  pipe  ;  the  air-hole  is  then  plugged,  and  the 
inside  face  of  the  dam  is  wedged  up  in  the  same  manner  as 
the  outside.  When  exposed  to  considerable  pressure  a  spherical 
dam  of  this  kind  is  found  to  slide  inwards  a  little.  One  which 
was  put  in  at  Churprinz  Mine,  Freiberg,  shifted  19 J  inches 
(0.50  m.)  in  the  first  fourteen  hours  after  it  had  been  closed,  and 
23!  inches  altogether  in  the  first  ten  days;  after  that  the  motion 
was  exceedingly  slow,  in  fact,  almost  imperceptible ;  but  it  did 
not  absolutely  cease  for  several  years. 

Fig.  496*  is   a  dam  in  an  abandoned  shaft,  intended  to  shut 

*  Gallon,  Lectures  on  Mining,  vol.  ii.,  plate  Ixxvi.,  fig.  409. 


DRAINAGE. 


433 


FIG.  496. 


off  any  possible  influx  of  water  into  the  adjacent  workings  in 

case  the  tubbing  should  fail.     It  consists  of  a  strong  arch  of 

masonry,  covered  by  a  thick  layer  of  clay  and  a  pavement   of 

stones.     The  clay  will  keep  the  dam  stanch  even  if  the  masonry 

becomes  slightly  cracked  from 

movements    of    the    ground, 

and  the  object   of  the  stone 

pavement    is  to   prevent  the 

clay  from  being  washed  away 

suddenly  in   the  event   of   a 

large  crack  being  formed.  The 

vertical  pipe  serves  to  carry 

down   the   water  during  the 

erection  of  the  dam. 

A  temporary  dam  is  some- 
times required  close  to  a  shaft, 
in  order  to  keep  back  the 
water  of  the  mine,  and  pre- 
vent it  from  drowning  the 
pumps  while  they  are  being 
repaired.  A  strong  and 
tightly-fitting  hinged  door 
may  suffice  for  the  purpose; 
in  the  Furness  district  the 
door-frame  is  set  in  a  very 
massive  structure  of  concrete, 
brickwork  and  steel  rails.  A 
large  pipe  is  put  in  at  the 
bottom  and  fitted  with  a  good 
valve,  which  enables  the  water 
to  be  let  out  gradually  when 
the  pumps  are  once  more 
ready  for  work. 

In  spite  of  all  precautions    o 
the   miner   generally   has   to 

contend  with  water  which  percolates  into  the  workings.  Four 
methods  of  getting  rid  of  it  are  available — viz.,  drainage  tunnels, 
siphons,  winding  machinery  and  pumps. 

DRAINAGE  TUNNELS. — An  adit,  day-level,  or  sough,  is  a 
nearly  horizontal  tunnel  with  one  end  opening  at  the  surface, 
allowing  the  water  to  drain  away  naturally.  In  hilly  countries 
mines  are  often  worked  entirely  by  adits,  and  even  for  the  deeper 
workings  the  adit  presents  several  advantages:  it  lessens  the 
quantity  of  water  percolating  into  them ;  it  diminishes  the  height 
to  which  the  water  has  to  be  pumped ;  if  the  contour  of  the  sur- 
face permits  it,  its  outflow  may  be  utilised  for  producing  water 
power;  and  lastly,  it  affords  a  natural  discharge  for  water  used  in 
driving  hydraulic  engines  underground.  On  account  of  these 

2  E 


SCALE 


234.56789 


2  3  METRES 

10    II     12   13  FEET 


434  ORE  AND  STONE-MINING. 

very  important  advantages,  some  long  and  costly  adits  have  been 
driven  in  certain  metalliferous  districts. 

Thus  in  the  Hartz,  the  Ernest  Augustus  adit  or  drainage  tunnel, 
("  Ernst  August  Stolln  ")  has  been  driven  a  distance  of  nearly  6 J 
miles  into  the  Clausthal  district.  The  total  length  of  the  adit, 
including  its  branches,  is  no  less  than  14  miles.  It  intersects 
many  of  the  lodes  at  a  depth  of  400  yards  from  the  surface.  The 
total  cost  of  this  adit  is  estimated  at  £85,500.* 

Another  long  adit  is  the  celebrated  "  Rothschonberger  Stolln," 
which  unwaters  some  of  the  most  important  mines  at  Freiberg  in 
Saxony,  The  length  of  the  main  or  trunk  adit  is  more  than  8J 
miles;  the  gradient  of  the  greater  part  of  it  is  only  ri8  inch  in 
100  yards.  Branches  of  this  adit  among  the  mines  are  more 
than  1 6  miles  in  length,  so  that  the  total  length  of  the  main 
tunnel  with  its  ramifications  amounts  to  about  25  miles.  Most 
of  the  mines  are  now  drained  by  it  to  a  depth  of  250  to  300  yards. 
The  cost  of  the  main  tunnel  was  .£359,334,  or  nearly  £24  per 
yard,  but  this  includes  the  cost  of  eight  shafts,  heavy  expenses 
for  pumping  from  these  shafts,  the  walling  of  the  adit  for  f  mile, 
and  all  general  expenses.  The  length  of  time  occupied  in  driving 
this  adit  was  thirty- three  years. 

The  "  Kaiser  Josef  Erbstolln,"  in  Hungary,  is  another  remark- 
able mining  tunnel,  which  was  commenced  in  1782  and  com- 
pleted in  1878,  at  a  total  cost  of  4,599,000  florins.  It  is  loj 
miles  in  length,  extending  from  the  river  Gran  to  the  town 
of  Schemnitz,  where  it  intersects  the  lodes  at  depths  vary- 
ing from  300  to  600  yards  according  to  the  contour  of  the 
surface. 

In  Bohemia  I  may  mention  the  "  Kaiser  Josef  II."  adit  which 
drains  the  Pribram  mines.  The  length  from  the  mouth  to  the 
Stefan  shaft  is  4j  miles,  and  the  side  branches  bring  up  the 
total  length  to  13!  miles. 

The  great  adit  of  the  Mansfeld  copper  mines  was  begun  in 
1 809,  and  was  seventy  years  in  course  of  construction.  It  reaches 
from  Friedeburg  on  the  Saale  to  Eisleben.  The  first  part  was 
driven  across  the  measures,  and  is,  in  fact,  a  crosscut,  and  it  was 
then  continued  along  the  strike  of  the  cupriferous  seam.  The 
total  length  is  now  21  miles  (33,900  m.).  All  the  workings  below 
its  level,  extending  for  a  distance  of  more  than  TI  miles  (i 8  km.), 
have  their  water  pumped  into  it.  The  adit  was  driven  with 
a  rise  of  i  in  7200  (J  inch  in  100  yards).  It  is  9  feet  10  inches 
high  (3  m.),  and  6  feet  across  (1*85  m.),  in  the  middle  where  it  i& 
widest.  The  bottom  part,  5  feet  8  inches  in  height,  was  carefully 
kept  in  the  Rothliegendes  so  as  to  prevent  percolation  into  the  work- 
ings. Cross-timbers  (spreaders)  were  put  in  about  5  feet  above  the 

*  Bauerman,  "  Note  on  the  new  deep  adit  in  the  Upper  Hartz  Mines, " 
Irans.  Min.  Assoc.  Cornwall  and  Devon,  1868,  p.  n. 


DRAINAGE.  435 

floor  and  serve  to  support  a  single  line  of  rails  and  a  gangway  of 
planks,* 

The  adit  at  Monteponi,f  in  Sardinia,  recently  finished,  is  3f 
miles  (6  kil.)  in  length,  and  relieves  the  mine  of  its  water  for  an 
additional  depth  of  about  160  feet  (50  m.). 

The  great  County  adit  in  Cornwall  was  driven  for  the  purpose 
of  draining  the  Gwennap  copper  mines,  and  it  was  pushed  on 
to  Redruth.  This  adit  differs  from  those  just  mentioned  by 
the  fact  that  it  commences  in  the  mining  district  itself,  and 
though  the  length  of  all  the  drivages  amounts  to  more  than  30 
miles,  the  water  from  the  most  distant  mine  does  not  run  more 
than  6  miles  before  reaching  daylight.  The  average  depth  is 
only  70  or  80  yards  from  the  surface.  In  fact  this  great  adit, 
though  a  work  of  great  utility  when  the  Gwennap  district  was  in 
a  flourishing  condition,  is  merely  a  network  of  shallow  tunnels, 
often  driven  along  the  lodes  themselves,  and  therefore  for  bold- 
ness of  execution  cannot  for  one  moment  be  compared  to  the 
great  adits  in  Germany  and  Hungary. 

The  Blackett  level  in  Northumberland  is  an  adit  which  has 
been  driven  a  distance  of  about  4}  miles,  and  which  will  have 
to  be  extended  about  2  miles  further  before  arriving  at  Allen- 
heads.  Its  depth  from  the  surface  at  that  place  will  be  about  200 
yards. 

The  main  part  of  the  Halkyn  tunnel  in  Flintshire  has  now 
reached  a  total  length  of  4  miles.  The  branch  which  goes  out  to 
Rhosesmor  Mine  is  nearly  half  a  mile  long  and  a  second  branch 
has  been  commenced.  The  greatest  depth  from  the  surface  is  230 
yards,  and  the  average  depth  under  Halkyn  Mountain  about  215 
yards.  The  length  and  depth  of  the  adit  are  not  remarkable ;  but 
the  quantity  of  water  discharged  is  a  matter  of  interest  and  impor- 
tance. It  is  estimated  that  this  adit  is  now  discharging  15 
million  gallons  or  66,000  tons  of  water  in  24  hours,  although  the 
outflow  is  purely  natural,  for  no  mines  are  pumping  water  into  it, 
It  is  easy  to  understand  that  the  Rhosesmor  Mine,  though 
provided  with  powerful  pumping  machinery,  was  unable  to  cope 
with  the  springs  it  encountered. 

In  the  "United  Kingdom,  where  the  land  and  the  minerals  are 
parcelled  out  among  various  owners,  an  undertaking  of  this 
kind  requires  a  special  Act  of  Parliament,  for  otherwise  one 
obstinate  proprietor  might  bar  the  way  altogether,  or  mines 
drained  by  the  adit  might  refuse  to  pay  for  the  advantages  they 
received.  Before  the  Halkyn  tunnel  was  driven,  the  area  which 
appeared  likely  to  be  benefited  was  duly  determined,  and  the 

*  Der  Kupfersctiieferlerglau  und  der  Hilttenletrieb  zur  Verarleitung  der 
gewonnenen  Minern  in  den  beiden  Kreisen  der  Preuss.  Prov.  /Sacksen.  Halle 
an  der  Saale,  1889,  page  48. 

t  Pellati,  "I  Progress!  nelle  Industrie  Minerarie  e  Mineralurgiche 
Italiane,"  Jndustria,  vol.  v.,  1891,  p.  637. 


436  ORE  AND  STONE-MINING. 

mines  now  worked  within  it  have  to  pay  a  royalty  to  the 
tunnel  company  for  every  ton  of  ore  they  raise. 

Fired  by  the  success  of  the  Halkyn  adit,  which  has  proved  a 
lucky  investment  for  the  shareholders,  a  company  has  lately 
commenced  driving  a  similar  tunnel  in  the  Llanarmon  district. 

The  United  States  may  fairly  boast  of  the  Sutro  Tunnel,  which 
enters  the  workings  on  the  Comstock  lode  at  a  depth  of  1700  feet 
from  the  surface.  Work  was  begun  on  a  small  scale  in  October 
1869,  and  the  tunnel  was  "holed"  into  the  workings  of  the 
Savage  Mine  in  July  1878.  The  length  of  the  main  tunnel  is 
3 1  miles,  and  the  cost  of  excavating  it  and  timbering  it  up  to  the 
date  of  its  completion,  September  i,  1878,  was  $1,367,577.  To 
this  must  be  added  $296,724  for  enlarging  the  heading,  $384,824 
for  cutting  a  drainage  channel  at  the  bottom,  of  the  tunnel  and 
lining  it  with  wooden  launders  or  drain  boxes,  and  the  cost  of 
repairs  $43,441,  making  the  total  cost  of  the  main  tunnel  up  to 
October  1881,  $2,096,566.  This  sum  does  not  include  the  expenses 
of  management  of  the  company.* 

The  size  of  the  adit  at  first  was  10  feet  high  clear  and  15 \  feet 
wide ;  but  after  366  yards  had  been  driven  the  dimensions  were 
reduced  to  6  feet  high  clear  by  5  feet  wide. 

In  the  original  scheme  it  was  proposed  to  sink  four  shafts  and  ex- 
pedite the  work  by  having  nine  points  of  attack ;  however,  this  plan 
could  not  be  carried  out.  The  first  two  shafts  were  sunk  down  to  the 
level  of  the  tunnel,  but  the  quantity  of  water  met  with  proved  such 
an  obstacle  that  the  tunnel  was  practically  driven  entirely  from 
one  end. 

Work  with  machine  drills  was  begun  in  April  1874,  and  the 
height  of  the  heading  was  raised  to  9^  feet,  and  the  width  to  13 
feet,  both  outside  the  timber.  In  1875  and  1876  the  monthly 
progress  was  on  an  average  308^  feet.  Much  of  the  tunnel, 
indeed  45*5  per  cent,  of  the  total  length,  had  to  be  timbered. 

In  addition  to  the  main  tunnel  there  are  branches  along  the 
course  of  the  lode.  In  October  1880,  the  length  of  the  north 
branch  was  4403  feet,  and  that  of  the  south  branch  4114  feet. 
Both  branches  are  8  feet  in  width  by  7  in  height  clear. 

The  quantity  of  water  running  out  daily  in  1879  was  12,000 
tons,  at  a  temperature  of  123°  F.  (50*5  C.)  when  leaving  the  mouth 
of  the  tunnel.  All  this  water  would  otherwise  have  been  pumped 
to  the  surface,  at  a  cost  estimated  at  $3000  a-day. 

The  obstacles  to  the  progress  of  the  work  were  very  great ;  not 
only  was  the  heat  extreme,  but  swelling  ground  was  encountered 
which  snapped  the  strongest  timber.  Thanks,  however,  to  the 
untiring  energy  of  Mr.  Adolph  Sutro,  the  difficulties  were  at 

*  Eliot  Lord,  "Comstock  Mining  and  Miners."  Monographs  of  the  U.  S. 
Geol.  Survey,  vol.  iv.,  p.  342.  Washington,  1883.  There  is  an  error  of 
$4000  either  in  one  of  the  items  or  in  the  total ;  but  I  give  the  figures  as 
they  stand  in  the  Keport.— C.  L.  N.  F. 


DRAINAGE.  437 

last  successfully  overcome,  and  this  great  work  will  long  remain 
as  a  monument  to  his  foresight,  skill,  and  patient  pertinacity. 

The  Atlantic- Pacific  tunnel,  which  was  commenced  in  1880  and 
then  stopped  for  a  time,  is  intended  to  pierce  the  heart  of  the 
Rocky  Mountains,  under  Grey's  Peak,  Colorado.  It  will  be 
driven  from  both  sides  of  the  watershed,  and  will  have  a  total 
length  of  4}  miles  from  end  to  end. 

SIPHONS. — Siphons  are  used  for  draining  mines  in  a  few 
special  cases  in  which  the  barrier  over  which  the  water  has  to  be 
raised  is  very  decidedly  less  than  33  feet. 

The  workings  of  a  shallow  mine  in  North  Wales  are  kept  clear 
of  water  by  a  siphon  made  of  ij-inch  gas-pipe.  At  the  crown 
there  is  an  iron  tank  full  of  water,  the  contents  of  which 
can  be  run  into  the  siphon  by  a  3 -inch  pipe  in  order  to  start 
it. 

At  Mountfield  gypsum  mine,  in  Sussex,  the  water  is  brought  to 
the  shaft  from  the  neighbourhood  of  the  working-face,  a  distance 
of  300  yards,  by  a  siphon  also  made  of  i  J-inch  gas-pipe.  It  has 
two  branches,  but  only  one  is  working  at  a  time.  The  water 
is  lifted  a  height  of  2  2  feet.  When  the  water  in  the  workings  sinks, 
so  that  there  is  a  danger  of  the  siphon  running  dry,  the  foreman 
moves  a  lever  which  brings  a  pad  of  india-rubber  against  the  outlet 
of  the  pipe,  and  so  keeps  it  full  and  ready  to  act  the  next  time  it  is 
wanted.  A  force  pump  is  set  up  at  the  far  end  of  the  workings 
for  filling  the  siphon  if  b}~  any  chance  the  water  has  run  out. 

WINDING  MACHINERY.— When  a  mine  cannot  be 
drained  by  tunnels  or  siphons,  it  is  necessary  to  raise  the  waiter 
mechanically,  either  to  the  surface,  or  at  all  events  to  an  adit 
through  which  it  can  flow  out  naturally.  If  the  quantity  is  not 
excessive,  it  is  often  convenient  to  use  the  winding  machinery, 
and  draw  up  the  water  in  special  buckets  (water-barrels)  or  tanks. 
The  bucket  may  be  tilted  over  on  reaching  the  surface,  or  it  may 
be  emptied  by  opening  a  valve  at  the  bottom. 

This  means  of  raising  water  is  commonly  adopted  in  sinking 
shafts,  when  it  may  be  desirable  to  wait  till  the  whole  or  a 
portion  of  the  pit  is  completed,  before  putting  in  the  final  pump- 
ing machinery.  The  water  is  usually  lifted  by  hand  into  the 
bucket  or  tank,  an  operation  involving  a  good  deal  of  labour. 
Some  of  the  baling  may  be  avoided  by  collecting  as  much  as 
possible  of  the  inflow  in  a  cistern  above  the  bottom,  and  drawing 
off  its  contents  by  a  hose  into  the  bucket.  This  device  is  of  no 
use  for  the  water  actually  at  the  bottom,  but  baling  may  be  dis- 
pensed with  even  in  this  case  by  the  adoption  of  an  ingenious 
arrangement  invented  by  Mr.  Galloway,  and  applied  very  success- 
fully by  him  in  sinking  a  shaft  near  Cardiff*  (Figs.  497  and 
498). 

*  "Sinking  Appliances  at  Llanbradacb,"   Trans.  South  Wales  lust.  Eng, 
vol.  xvi.,  1888,  p.  117. 


438 


ORE   AND   STONE-MINING. 


By  means  of  a  pump  at  the  surface,  the  air  is  constantly  being 
exhausted  from  a  pipe,  which  descends  the  shaft  and  terminates 
in  a  long  piece  of  flexible  hose  provided  with  a  stopcock.  When 
the  cylindrical  water-barrel  has  been  lowered  to  the  bottom  of  the 

shaft  and  is  standing  with  its  base  in 
the 


FIGS.  497,  498. 


,  door  for  entering  barrel 
if  required;  b,  flat  cast- 
iron  valve  attached  to  the 
spindle  h;  c  d,  bottom 
plate  of  the  barrel ;  e,  sec- 
tion of  the  valve  showing 
universal  joint  attach- 
ment ;  I,  water-pipe,  pro- 
vided at  the  end  Jc  with 
a  coupling  to  which  the 
suction  hose  is  attached  ; 
m,  water-gauge. 


water,  the  flexible  hose  is  quickly 
attached  to  it  at  the  point  k  by  an 
instantaneous  coupling,  and  the  cock  is 
turned.  Water  is  at  once  sucked  up 
through  the  valve  6,  and  as  soon  as  the 
gauge-glass  m  shows  that  it  has  reached 
the  desired  height,  the  stopcock  is 
closed  and  the  hose  uncoupled.  On 
arriving  at  the  top  of  the  pit,  the  water- 
barrel  is  lowered  on  to  a  trolley  carry- 
ing a  projecting  conical  block  of  wood, 
which  knocks  up  the  valve  and  allows 
the  contents  to  run  out. 

It  was  possible  with  the  aid  of  this 
contrivance,  while  sinking  a  shaft  in 
hard  sandstone  at  the  rate  of  5  to  5^ 
yards  per  week,  to  cope  with  an  influx 
of  5000  gallons  (22*7  cubic  metres)  of 
water  per  hour  at  the  bottom. 

A  water-barrel  can  be  filled  auto- 
matically, when  it  can  be  made  to 
plunge  into  a  deep  cistern  or  collect- 
ing pit  (sump).  Mr.  Galloway's 
arrangement  is  shown  by  Figs.  499  and 
500.  The  former  represents. ais  auto- 
matic water-tank  with  one  side  partly 
removed  :  a  is  the  winding-rope,  b  the 
tank,  which  is  guided  in  its  descent  and 
ascent  by  the  studs  c  (Fig.  500)  run- 
ning upon  the  guide  ropes  e.  At  the 
surface  the  tank  is  further  steadied  by 
side  grooves,  made  of  angle-iron  d, 
which  clasp  the  studs.  When  the  tank 


is  lowered  into  the  cistern,  the  valve  k  opens  of  itself  and  lets  the 
water  rush  in.  It  is  then  wound  up  to  the  top,  where  the  short  lever 
at  o  comes  in  contact  with  the  piece  of  timber p  ;  the  rod  attached 
to  the  valve  is  lifted,  and  the  water  rushes  out  by  the  sloping 
mouth  /  into  the  wooden  trough  or  launder  m.  The  bar  p  is 
movable  about  the  point  <?,  but  it  is  kept  down  by  the  weight  u 
attached  to  the  chain  s  ;  I  is  one  of  the  pieces  of  timber  to  which 
the  fixed  guides  are  fastened,  and  lastly,  w  is  the  suspending  bow 
which  passes  quite  round  the  tank  and  forms  a  projecting  loop  at 
the  bottom.  This  bow  protects  the  bottom  of  the  tank  while  it 


DRAINAGE. 


439 


is    standing  in  the  cistern.     The  tank   holds    212    gallons  (963 
litres),  and  can  be  drawn  up  24  times  an  hour  from  a  depth  of 

FIG.  499. 


2  METRES 


190  yards;   it  is  therefore  capable  of  raising  5000  gallons  (227 
cubic  metres)  in  that  time. 

The  arrangement  just  described  was  employed  by  Mr.  Galloway 
when  sinking,  but  it  is  equally  available  as  a  permanent  method 


440 


ORE  AND  STONE-MINING. 


FIG.  500. 


of  drainage  when  the  quantity  of  water  is  not  considerable. 
The  water  is  allowed  to  accumulate  in  a  sump  at  the  bottom 
of  the  shaft  during  the  day-time,  for  instance,  and  at  night,  when 
no  mineral  is  being  wound,  the  ordinary  cage  is  taken  off  and 

the  water-barrel  substituted  for  it. 
The  water-barrel  is  also  useful  as  an 
auxiliary,  when  the  ordinary  pumping 
machinery  of  a  mine  is  unable  to  cope 
with  some  unusual  influx  of  water,  or 
has  to  be  stopped  for  repairs.  It  is 
not  necessary  to  adopt  the  construction 
shown  in  the  figure,  though  that  is  a 
particularly  advantageous  one.  The 
vessel  for  receiving  the  water  and 
bringing  it  up  is  sometimes  made  like 
a  large  mine  waggon ;  it  is  drawn  up 
in  the  cage,  like  a  "  tub "  of  mineral, 
and  is  discharged  at  some  point  in 
close  proximity  to  the  pit-top.  At  the 
Yan  mine  a  tub  of  this  kind  holds 
about  220  gallons  (i  cubic  metre).  As 
a  makeshift,  an  ordinary  mine- skip 
may  be  turned  into  a  water-barrel  by 
fixing  a  wooden  box  inside  it  with  a 
valve  in  the  bottom. 

Automatic  emptying  and  filling  is 
also  obtainable  where  the  mine  is 
worked  by  inclines  or  "slopes,"  and 
the  arrangement  used  by  Mr.  Bowden* 
(Figs.  501  to  503)  has  the  merit  of 
allowing  several  tanks  to  be  used  in 
the  place  of  a  single  large  one,  which 
might  be  too  unwieldy  for  the  mine. 
Each  tank  has  an  iron  door  at  the  rear 
end  opening  inwards,  and  a  wooden 
door  at  the  front  end  opening  out- 
wards. The  front  door  is  attached 
to  the  back  door  by  an  iron  rod,  so 
that  it  is  held  down  as  long  as  the  back 

door  is  shut ;  however,  the  back  door  can  open  independently  of 
the  front  door,  because  the  rod  has  a  sliding  link  at  the  rear  end. 
The  tipping  or  dumping  is  effected  by  the  small  wheels  above  the 
rear  axles.  They  have  a  wider  gauge  than  the  regular  wheels, 
and  as  each  tank  comes  up  to  the  surface,  they  are  taken  by  an 
upper  set  of  rails  and  tilt  up  the  rear  end.  If  the  track  upon 
which  they  travel  has  sufficient  gradient  towards  the  "  slope,"  the 

*  Bowden,  "  Tandem  Tanks  for  Hoisting  Water  from  Flooded  Slopes  " 
Trans.  Amer.  Inst.  M.  E.,  vol.  xx.,  1891,  p.  343. 


DRAINAGE. 


441 


tanks  will  run  down  of  themselves,  after  they  have  emptied  their 
contents  into  the  trough  at  the  top. 

PUMPS. — We  now  come  to  the  main  division  of  the  subject  of 
drainage,  for  the  standard  method  of  extracting  water  from 
underground  workings  is  by  some  form  of  pump. 

The  varieties  of  pumps  used  in  mines  are  numerous.  In  small 
sinkings,  hand-pumps,  either  direct-acting  or  rotary,  may  be 
applied;  steam-jet  pumps,  on  the  principle  of  the  Giffard 
injector,  and  pulsometers  are  also  used,  but  when  we  examine  the 

FIGS.  501,  502. 


FIG.  503. 


permanent    machinery  erected  at   large   mines    of   considerable 
depth,  we  find  that  the  prevailing  types  of  pumps  are  few. 

They  may  be  classified,  according  to  the  situation  of  the  engine 
working  the  pumps,  into : 

I.  Lifting  pumps  and  force  pumps  worked  by  power  transmitted  by 
rods  from  an  engine  at  the  surface  or  in  the  upper  workings. 
II.  Force  pumps  worked  direct  from  an  engine  immediately  attached 
to  them  at  or  near  the  bottom  of  the  workings. 

Class  I.— Engine  at  or  near  the  Surface,  Power  Trans- 
mitted by  Rods. 

We  may  consider  the  subject  under  the  following  four  heads : 

(a)  Motors. 
(6)  Kods. 

(c)  Pumps. 

(d)  Accessory  arrangements  :  counterbalances,  regenerators,  catches. 


442  ORE  AND  STONE-MINING. 

(a)  Motors. — The  engine  may  be  driven  by  wind,  compressed 
air,  water,  electricity,  steam,  or  petroleum,  (i)  Air. — Windmills 
have  the  disadvantage,  which  is  often  fatal,  that  the  power  is  not 
constant ;  the  same  may  be  said  of  water  power  derived  from 
brooks  and  rivers,  which  sometimes  dry  up ;  but  the  two  cases 
are  different.  Streams  dry  up  slowly  and  gradualty,  whilst  air 
currents  spring  up  or  die  away  suddenly.  By  erecting  an 
auxiliary  steam  engine,  which  can  be  set  to  work  if  the  wind 
fails,  the  evil  is  overcome;  and  this  remedy  is  adopted  at  the 
Mona  mines  in  Anglesey,  where  a  windmill  has  been  in  use  for 
many  years  for  working  pumps.  It  raises  water  from  a  depth 
of  80  fathoms  at  the  rate  of  about  90  gallons  a  minute.  As  the 
site  of  the  mine  on  Parys  Mountain  is  breezy,  there  is  wind 
enough  to  work  the  mill  for  about  one-half  of  the  time  pumping 
is  required.  A  very  large  saving  has  thus  been  effected  in  the 
coal  bills. 

(2)  Water. — Water  power  was  for  a  long  period  the  principal 
agent  employed  in  draining  mines,  and  it  is  still  of  the  greatest 
use  in  many  districts,  reservoirs  being  constructed  to  collect  and 
store  the  rainfall.  Some  idea  of  the  scale  upon  which  works  of 
this  kind  are  conducted  will  be  gathered  from  the  following 
figures  relating  to  the  Hartz  mines.*  In  1868  there  were 
"  sixty-seven  reservoirs,  covering  an  area  of  604  acres,  and 
having  a  total  storage  capacity  of  336  millions  of  cubic  feet." 

The  total  length  of  the  various  leats,  races,  and  other  water- 
courses, including  the  six  principal  adits,  is  about  170  statute 
miles.  The  net  power  extracted  is  reckoned  at  1870  horse-power, 
but  less  than  one-fourth  of  this  is  used  for  pumping. 

Water  power  is  applied  to  pumping  machinery  by  water- 
wheels,  turbines,  and  rotary  or  non-rotary  water-pressure  engines. 
Excepting  in  the  case  of  the  latter,  the  rotary  motion  has  to  be 
converted  into  a  reciprocating  motion  by  a  crank ;  and  further- 
more with  turbines,  the  speed  must  be  reduced  very  considerably 
by  intermediate  gearing. 

Overshot  wheels  are  the  commonest  forms  of  prime  movers 
for  working  pumps  by  water-power  ;  they  are  frequently  from 
40  to  50  feet  in  diameter,  and  at  Great  Laxey  Mine,  in  the 
Isle  of  Man,  one  of  the  wheels  is  no  less  than  72  feet  6 
inches  in  diameter,  and  6  feet  in  the  breast.  The  power  is  con- 
veyed from  the  water-wheel  by  a  connecting  rod  to  a  quadrant 
or  "  bob,"  like  a  bell-crank,  placed  above  the  shaft,  and  when, 
owing  to  the  contour  of  the  ground,  the  wheel  has  to  be  erected 
at  a  distance,  it  is  often  connected  to  the  bob  by  the  so-called 
"  flat  rods,"  which  are  beams  of  wood,  bars  of  iron,  or  pieces  of 
wire  rope.  They  are  supported  by  pulleys  or  upright  oscillating 

*  Bauerman,  "  Notes  on  the  New  Deep  Adit  in  the  Upper  Hartz  Mines," 
Rep.  Miners'  Assoc.  Cornwall  and  Devon,  1868,  p.  21. 


DRAINAGE.  443 

beams,  and  travel  backwards  or  forwards  with  the  motion  of  the 
crank. 

Water-pressure  engines  share  with  turbines  the  advantage  of 
being  able  to  utilise  any  amount  of  fall,  and  the  direct-acting 
water-pressure  engine  can  be  applied  immediately  to  the  main 
rod  of  the  pumps. 

(3)  Steam  is,  however,  the  power  used  par  excellence  for  working 
pumping  machinery,  and  the  great  inventions  of  Newcomen  and 
Watt  owed  their  birth  to  the  necessities  of  mines,  which  could  no 
longer  be  drained  by  the  water  power  available  on  the  spot. 

The  principal  type  of  engine  is  that  known  as  the  Cornish 
engine;  it  is  a  single-acting  condensing  beam  engine,  working 
expansively,  having  the  number  of  strokes  regulated  by  an 
arrangement  called  a  cataract.  The  cylinder  of  the  Cornish 
engine  is  sometimes  inverted  and  stands  over  the  shaft,  the  main 
rod  of  the  pumps  being  attached  directly  to  the  piston-rod.  This 
type  of  engine,  known  as  the  Bull  engine  in  Cornwall,  dispenses 
with  the  heavy  beam,  but  it  has  the  great  disadvantage  of 
obstructing  the  mouth  of  the  shaft.  This  objection  is  quite 
enough  to  forbid  its  use  under  ordinary  circumstances.  On  the 
other  hand,  the  mere  reversal  of  the  cylinder  or  cylinders,  while 
retaining  the  beam,  is  often  resorted  to  on  account  of  the 
advantage  it  gives  in  greater  stability  and  diminished  cost  of  the 
engine-house. 

A  disadvantage  of  the  Cornish  engine  is  the  fact  that  when  it 
works  with  a  high  rate  of  expansion,  there  are  great  shocks  and 
jars  to  all  the  parts  of  the  machinery.  The  heavy  mass  of  rods 
and  its  connections  is  started  with  a  jerk,  and  naturally  all  the 
joints  must  suffer. 

The  compound  engine,  invented  by  Woolf  and  tried  many  years 
ago  in  Cornwall,  starts  more  gradually  and  causes  less  strain  upon 
the  pump-rods  and  machinery  generally.  The  cylinders  may  be 
placed  one  above  the  other,  or  side  by  side.  At  Ernst  IV.  shaft, 
Mansfeld,  there  are  three  cylinders  placed  side  by  side  across  the 
line  of  the  beam,  the  high-pressure  cylinder  in  the  middle  between 
the  two  low-pressure  cylinders.  The  three  piston-rods  are  attached 
to  a  crosshead  which  is  connected  to  the  beam.  The  cylinders 
are  inverted. 

Kley,  of  Bonn,  has  constructed  compound  engines  with  steam 
acting  on  both  sides  of  the  pistons.  He  makes  the  excess  of  the 
weight  of  the  rod  over  that  of  the  counterbalances  sufficient 
to  raise  only  half  the  weight  of  the  water  and  to  overcome  the 
friction ;  and  then  in  the  descending  stroke  of  the  rod  the  steam 
again  acts  upon  the  pistons  and  so  makes  up  for  the  insufficiency 
in  weight.  As  the  steam  acts  upon  both  sides  of  the  piston,  the 
same  amount  is  consumed,  it  is  true ;  but  a  smaller  cylinder  will 
do  the  work,  and  the  original  cost  of  the  engine  is  lessened. 

Fly-wheels  have  the  advantage  of  setting  the  pumps  and  main 


444 


ORE  AND  STONE-MINING. 


rod  in  motion  without  the  injurious  jerk  which  is  inseparable 
from  the  Cornish  engine  worked  at  a  high  rate  of  expansion, 
besides  reducing  the  risks  of  damage  if  a  piston-rod  breaks. 

Kley  has  put  up  several  pumping  engines  in  Belgium,  France, 
and  Germany,  of  30  to  560  horse-power,  with  a  fly-wheel  which 
serves  solely  to  regulate  the  stroke  of  the  piston,  so  that  the 
crank  always  stops  before  or  after  the  dead  point  till  the  cataract 
starts  another  stroke.  The  machines  are  double-acting  compound 
beam  engines. 

M.  Guinotte,  the  well-known  Belgian  engineer,  also  adopts  the 
fly-wheel,  and  the  machines  he  has  erected  at  Mariemont  and  else- 
where are  single-acting  rotary  engines  with  one  cylinder.  The 
peculiarity  of  his  fly-wheel  is  that  he  can  weight  it  in  any  way  he 
pleases ;  and  he  so  overcomes  the  difficulty  which  occurs  in  other 
rotary  machines  of  its  being  impossible  to  work  them  below  a  certain 
His  object  is  to  make  the  speed  slow  at  the  beginning  and 


FIG.  504. 


SCALE  HOOO 


end  of  the  stroke,  so  as  to  avoid  the  injurious  shocks  to  the 
valves  and  machinery  generally  from  sudden  starts  and  stoppages. 
The  cylinders  of  a  pumping  engine  may  be  placed  horizontally, 
an  arrangement  which  effects  a  decided  saving  in  the  cost  of 
foundations  and  in  that  of  the  engine-house.  The  engine  lately 
erected  at  the  Otto  IY.  shaft  at  Mansfeld  (Fig.  504)  is  a 
horizontal  double-acting  compound  engine  with  a  fly-wheel, 
working  two  pump-rods  by  means  of  quadrants.  A  is  the  high- 
pressure  cylinder,  B  the  low-pressure  cylinder,  C  the  fly-whtel, 
D  and  E  are  quadrants,  connected  by  F,  which  raise  and  lower  the 
two  rods  G  and  H.  The  cylinder  A  is  5  feet  2^  inches  (1*590 
m.)  in  diameter,  and  B  8  feet  i  J  inches  (2-480  nT.).  The  stroke 
of  the  engine  is  8  feet  8f  inches  (2'66o  m.),  and  the  fly-wheel 
makes  nj  revolutions  per  minute.  When  working  at  this  speed 
it  is  reckoned  that  it  raises  3521  gallons  (16  cubic  metres)  of 
water  per  minute,  a  total  height  of  906  feet  (276-35  m.).  The 
water  is  salt,  and  has  a  specific  gravity  of  1*15.  Each  rod  works 
a  pump  at  the  bottom,  with  a  fixed  hollow  plunger  27!  inches  (705 
mm.)  in  diameter  and  a  moving  "  pole  case,"  which  lifts  the  water  to 
a  height  of  463  feet  (141*1  m.).  Here  the  work  is  taken  up  by  a 


DRAINAGE,  445 

Rittinger  pump  with  plungers  of  27 J  inches  (700  mm.)  and  21 J 
inches  (540  mm.),  and  the  water  is  raised  by  it  to  the  adit  level, 
an  additional  height  of  443  feet  (135*25  m.).  The  stroke  of  the 
rods  is  2  metres.  When  the  full  power  of  the  engine  is  not 
required,  one  rod  can  be  disconnected  and  the  other  is  balanced 
by  an  accumulator. 

At  Diepenlinchen,  near  Stolberg,  an  engine  of  similar  construc- 
tion has  been  put  up  within  the  last  few  years,  the  dimensions  of 
the  two  cylinders  being  almost  the  same  as  those  adopted  at 
Mansfeld.  The  problem  at  Diepenlinchen  is  to  raise  2640  gallons 
(12  cubic  metres)  of  water  per  minute  from  a  depth  of  328  yards 
(300  m.). 

The  compound  engine,  with  its  two  cylinders  placed  tandem 
fashion  horizontally,  is  largely  used  by  Davey,  whose  principal  im- 
provement consists  in  his  patent  differential  valve  gear,  which 
combines  the  action  of  a  cataract  with  that  of  a  slide  valve. 

(4)  Petroleum. — Where  coal  is  very  expensive  owing  to  the  cost 
of  carriage,  a  petroleum  engine  may  be  a  convenient  source  of 
power  for  pumping  on  a  small  scale. 

(b)  Hods. — Having  discussed    the  principal  forms  of  engines 
used  for  pumping  at  mines,  it  now  remains  to  consider 
how  their  power  is  applied  to  the  pumps  themselves.          FIG.  505. 

The  usual  mode  of  transmission  is  by  rods  made 
of  wood,  wrought  iron,  or  steel. 

Wooden  rods  are  commonly  constructed  in  this 
country  of  pitch-pine  beams  of  square  section,  united  by 
plates  of  iron  or  mild  steel  (strapping  plates,  a,  b,  c, 
Fig.  505),  which  are  held  together  by  bolts,  the  butt  end 
of  one  beam  being  brought  against  the  butt  end  of  the 
next.  Other  forms  of  joints,  such  as  the  scarf  joint, 
are  met  with. 

The  iron  and  steel  rods  are  either  solid  bars  of  round 
iron  or  steel,  or  beams  built  up  from  angle-iron  or 
angle-steel,  so  as  to  obtain  the  desired  stiffness  without 
undue  weight.  It  is  proposed  to  use  Mannesmann 
seamless  steel  tubes,  which  can  be  rolled  in  lengths  of 
70  feet,  as  rods  for  pumps. 

The  long  beam,  made  up  of  a  succession  of  pieces, 
constitutes  what  is  called  the  main  rod  or  spear-rod. 
It  hangs  down  the  shaft,  either  from  the  end  of  the 
beam  of  the  engine,  or  from  a  quadrant  such  as  is 
shown  in  Fig.  504,  when  the  cylinder  of  the  pumping  engine 
is  horizontal.  In  order  to  prevent  it  from  vibrating  sideways, 
it  has  to  be  guided;  wooden  rods  are  guided  by  cross  bars  of 
timber  placed  in  the  shaft,  and  they  are  protected  from  wear  by 
pieces  of  plank  (lining  boards),  which  are  renewed  from  time  to 
time.  The  round  iron  or  steel  rods  are  kept  in  position  by 
suitable  collars  fixed  upon  timber  or  metal  supports. 


446 


ORE  AND  STONE-MINING. 


If  the  shaft  is  inclined,  as  so  often  happens  in  vein-mining,  the 
main  rod  has  to  be  supported  at  suitable  intervals  by  cylinders  of 
cast  iron  or  steel,  known  as  "  shaft  rolls."  The  roller  turns  upon 
a  spindle  as  the  main  rod  moves  up  and  down  (Fig.  539). 

The  bane  of  some  mining  districts,  such  as  Cornwall,  is  the 
varying  inclination  of  many  of  the  pumping  shafts,  which  have 

been  sunk  along  the  dip  of 

FIG.  506.  the  veins.     In  cases  of  this- 

kind  it  is  necessary  to  make 
bends  in  the  main  rod  cor- 
responding to  the  crooked- 
ness of  the  shaft.  Four 
methods  of  making  an 
angle  in  the  rod  are :  (i) 
the  V-bob;*  (2)  the  fend- 
off  bob ;  (3)  the  running- 
loop  ;  (4)  hydraulic  pistons. 
The  V-bob,  as  its  name 
implies  (Figs.  506  and  507),, 
^  is  a  V -like  frame,  some- 

**-&  &  thing  like  a  bell-crank,  in- 

terposed between  the  ends 

of  the  two  rods.  The  two  arms  of  the  V  are  made  of  strong 
beams  of  timber  strengthened  by  iron  plates  b  and  c,  and  con- 
nected by  two  straps  a,  which  prevent  their  being  pulled  apart. 
The  arms  are  arranged  so  that  each  is  at  right  angles  to  the 

FIG.  508. 


adjacent  end  of  the  rod  at  half  stroke.  At  the  point  of  the  V 
there  is  a  strong  pin  d  lying  in  brasses,  about  which  the  bob 
moves  as  a  centre.  It  is  usual  to  make  the  arms  at  least  20 

*  This  figure  and  several  of  the  others  relating  to  pumps  are  copied,  by 
rmission,  from  a  paper  on  "  Cornish  Mine  Drainage,"  by  Mitchell  and 


pei 
Letcher. 


forty-third  Ann.  Rep.  It.  Cornwall  Pol.  Soc.,  Falmouth,  1875. 


DRAINAGE. 


447 


inches  long  for  each  foot  of  the  stroke.  Therefore  for  a  stroke 
of  9  feet,  the  length  of  each  arm  would  be  9  x  i|,  or  15  feet. 

A  fend-off  beam  will  be  understood  from  Fig.  508,  which 
is  an  example  taken  from  Crenver  and  Abraham  Mine  in 
Cornwall.  It  is  a  long  beam,  strengthened  by  tie-rods,  moving 
about  a  strong  pin  working  in  a  block.  The  Cornish  rule  is  to 
make  the  beam  2\  times  as  long  as  the  stroke. 

The  running  loop  (Figs.  509  and  510)  is  sometimes  used  to 
save  the  expense  of  cutting  out  the  large  recess  (plat)  which  is 
required  in  the  case  of  a  V-bob  or  a  fend-off  beam.  The  two  parts 
of  the  main  rod,  c  and  d,  are  connected  by  two  loops  of  wrought 


FIG.  509. 


FIG.  510. 


FIG.  511. 


Side  View. 


Front  View. 


iron,  e,  of  which  one  only  can  be  shown  in  the  side  elevation. 
Each  loop  passes  round  the  two  pins,  which  are  the  axles  of 
the  two  wheels.  The  wheels  run  upon  flat  bars  of  wrought-iron, 
/,  laid  upon  the  sleepers,  b,  which  are  supported  by  the  strong 
cross-bearers,  a  a. 

West  and  Darlington  effect  the  change  of  direction  in  the  rods 
by  two  rams  or  plungers,  working  in  cylinders  connected  at  the 
bottom  (Fig.  511).  The  plunger  a  in  going  down  raises  the 
plunger  b,  to  which  the  main  rod  of  the  pumps  is  attached  by  a 
crosshead  and  two  side  straps.  There  is  a  valve  at  c,  through 
which  the  plunger  can  draw  in  a  little  water  to  make  up  for  any 
loss  through  the  stuffing  boxes. 

(c)  Pumps. — The  main  rod,  which  has  just  been  described,  is 
used  for  transmitting  the  motion  of  the  engine  to  a  pump  or 
several  pumps  in  the  shaft.  These  pumps  are  of  two  descrip- 


448  ORE  AND  STONE-MINING. 

tions :  (i)  lifting  pumps;  (2)  force-pumps.  The  lifting  pump, 
or  drawing  lift  (Fig.  512),  consists  of  the  wind-bore  or  suction 
pipe,  the  clack-piece  or  valve-box,  the  clack-seat  piece,  the  working 
barrel,  the  bucket  with  its  rod  and  the  column. 

The  wind-bore,  or  snore-piece,  as  it  is  sometimes  called,  is  a 
cylinder  of  cast-iron,  terminating  in  an  egg-shaped  or  a  flat  bottom, 
with  a  number  of  holes  through  which  the  water  is  sucked  up 
into  the  pump. 

The  clack-piece  is  a  short  cylinder  of  cast  iron  with  a  flat  side 
door  fastened  on  by  bolts,  the  object  of  which  is  to  enable  the 
valve  to  be  taken  out  and  renewed.  It  receives  the  seat  on  which 
a  clack  or  valve  works. 

The  clack  seat-piece  is  not  always  used ;  but  it  is  often  put 
in  as  a  matter  of  precaution,  in  case  the  regular  valve  should 
accidentally  fail  while  the  pumps  are  under  water.  If  a  mishap 
of  this  kind  occurs,  a  special  clack  can  be  lowered  on  to  the 
clack  seat-piece,  and  the  pump  can  be  worked  with  it  temporarily. 

The  working  barrel  is  a  cast-iron  cylinder,  carefully  bored  so 
that  the  bucket  may  work  in  it  smoothly  and  exactly ;  occasionally 
it  is  bushed  with  brass. 

The  bucket  is  merely  a  moving  valve,  consisting  usually  of  a 
hollow  cylinder  of  cast  iron,  surrounded  by  a  band  of  leather  or 
gutta-percha,  and  attached  to  a  rod  through  which  it  receives  its 
reciprocating  motion.  The  seat,  called  the  "  form,"  may  be  made 
for  a  single  valve  or  a  double  valve.  The  "  form  "  shown  in  Figs. 
513  and  514  is  made  for  one  valve,  and  it  is  held  by  a  stout  rod 
with  two  forks  or  "  prongs."  The  mode  of  attachment  of  the 
prong  a  to  the  form  b,  by  the  so-called  half-moons  c  and  cotters, 
is  evident  from  Figs.  514  and  515.  When  there  are  two  valves 
the  form  is  made  as  shown  by  Fig.  516  or  Fig.  517,  and  the  rod, 
now  called  a  "  sword,"  is  attached  by  a  central  blade  which  passes 
through  a  corresponding  slot  in  the  middle  rib. 

The  valve  itself  is  made  of  a  flat  piece  of  leather  riveted 
between  two  iron  plates  and  fastened  at  one  end  (Fig.  513)  by 
spikes  or  bolts,  or  of  two  similar  semi-circular  pieces  of  leather 
attached  at  the  circumference  (Fig.  516)  or  in  the  middle  of  the 
form  (Fig.  517).  In  either  case  there  is  a  band  of  leather  or 
gutta-percha  round  the  form  which  makes  the  bucket  fit  exactly 
in  the  working  barrel.  This  band  is  cut  out  in  the  shape  of  a  seg- 
ment, such  as  is  shown  in  Fig.  518,  and  is  then  bent  round  the 
form  and  kept  in  its  place  by  an  iron  hoop  or  ring.  Leather 
is  usually  employed,  and  is  sometimes  made  from  buffalo  hide,  in 
order  to  obtain  great  durability ;  with  gutta-percha  there  is  the 
advantage  of  being  able  to  utilise  a  worn-out  band  in  making 
a  new  one.  After  it  has  been  softened  in  hot  water  and  well 
kneaded  up  with  a  little  fresh  gutta-percha,  to  supply  the  waste, 
it  can  be  rolled  out  in  a  proper  mould  into  a  band  of  the 
•desired  shape.  Richardson's  composition  consists  largely  of 


DRAINAGE. 


449 


gutta-percha,  and  makes  a  durable  and  economical  pump-bucket. 
The  bucket  is  attached  to  the  rod  by  a  square  sliding  clasp  and  a 
cotter.  The  bucket-prong,  or  sword,  has  a  little  projecting  ridge 
(Fig.  514)  which  fits  into  a  corresponding  recess  in  the  end  of  the 
rod ;  when  the  clasp  has  been  drawn  over  and  the  key  inserted, 
the  joint  is  complete.  The  actual  rod  itself  may  be  of  wood  or 


FIG.  512. 


FIG.  513.   FIG.  514. 


FIG.  08. 


iron,  and  it  may  either  work  inside  the  column  or  outside. 
Fig.  512  shows  the  commoner  method  in  this  country,  but  both  here 
and  on  the  other  side  of  the  Atlantic  the  second  plan  is  employed. 
Fig.  519  represents  a  lifting  pump  used  in  mines  on  the  Corn- 
stock  lode.*  S  is  the  windbore  or  suction  pipe;  Y  the  fixed 
clack  or  valve ;  P  the  bucket,  with  its  valve  v,  moving  in  the 
working  barrel.  The  rod  to  which  it  is  fixed  passes  through  the 

*  Hague,  "  Mining  Industry,"  United  States  Geological  Exploration  of  the 
Fortieth  Parallel,  Washington,  1870,  p.  124. 

2  F 


450  ORE  AND  STONE-MINING. 

stuffing-box  gr,  and  is  connected  to  the  wooden  rod  R.  The 
column  of  pipes,  made  of  riveted  sheet  iron,  through  which  the 
water  is  lifted,  is  shown  by  C.  Three  sheet-iron  cylinders 
riveted  together  form  one  section.  Each  section  is  pro- 
vided at  both  ends  with  a  cast-iron  flange,  and  two 
adjacent  sections  are  fastened  together  by  bolts.  The  cast-iron 
pieces  H  carry  the  stuffing-box  and  join  the  column  to  the 
working  barrel.  Figs.  520  and  521  represent  the  mode  of  attach- 
ment of  two  sections,  and  also  the  manner  in  which  the  column  is 
held  in  the  shaft.  Lap-welded  sheet-iron  pipes  may  take  the 
place  of  the  riveted  pipes  of  the  figure. 

The  columns  of  pumps  in  this  country  are  generally  made  of 
cast-iron  pipes  with  flanges  ;  the  standard  length  is  9  feet.  The 
joint  is  made  by  inserting  a  ring  of  sheet  iron,  which  has  been 
wound  round  with  coarse  flannel  soaked  in  tar,  and  tightening 
the  bolts.  A  more  perfect  and  durable  connection  is  obtained  if 
the  flanges  are  properly  faced  and  provided  with  a  recess  for  an  india- 
rubber  or  a  gutta-percha  washer.  Pipes  of  sheet  iron  and  steel  have 
the  advantage  of  lightness,  an  important  matter  when  transport 
is  expensive,  and  it  may  be  hoped  that  pipes  of  rolled  steel 
made  by  the  Mannesmann  process  will  be  available  for  the 
rising  mains  of  mine-pumps ;  fewer  joints  will  be  required,  and 
the  column  will  be  lighter  and  less  troublesome  in  every  way. 

Wooden  pumps  have  not  disappeared  in  countries  where 
timber  is  abundant  and  metal  expensive ;  the  rising  mains  are 
formed  of  trees  bored  along  the  centre.  Wood  is  also  used  in 
certain  cases  when  the  mine  water  is  corrosive  ;  thus  at  the  Parys 
mine,  Anglesey,  where  the  water  is  highly  cupriferous,  pumps  of 
this  kind  have  to  be  employed.  The  wooden  pipes  made  by 
Wyckoff  &  Son,  of  Elmira,  N.Y.,  are  bored  white  pine  logs  turned 
outside,  strengthened  by  a  band  of  hoop-iron  wound  around  spir- 
ally, and  coated  with  asphalt.  Pipes  of  this  description  are  made 
with  bores  up  to  1 6  inches  in  diameter,  and  are  capable  of  resisting  a 
pressure  of  160  Ibs.  per  square  inch,  or  a  head  of  water  of  370  feet. 

The  disadvantage  of  the  arrangement  shown  in  Fig.  519  is 
that  if  a  bucket  fails,  whilst  the  stuffing-box  happens  to  be  sub- 
merged, the  "  lift  is  lost,"  in  other  words  the  pump  is  utterly 
useless;  whilst  with  the  ordinary  system  (Fig.  512),  the  bucket 
can  be  drawn  out  and  "  geared "  once  more.  To  remedy  this 
defect,  a  working  barrel  and  a  clack-piece  may  be  inserted  in 
the  column  ;  a  new  rod  and  bucket  can  then  be  lowered  into  it, 
and  made  to  work  until  the  water  is  sufficiently  mastered  for 
the  old  bucket  to  be  changed. 

On  the  other  hand,  the  stuffing-box  arrangement  can  claim 
the  advantage  of  making  the  buckets  last  longer.  No  doubt  the 
reason  of  this  is  that  the  stuffing-box  acts  as  a  guide  to  the  rod, 
and  prevents  irregular  friction  of  the  bucket  against  the  sides  of 
the  working  barrel. 


DRAINAGE. 


451 


The  force-pump  used  in  mines,  known  as  the 
plunger  pump  (Fig.  522),  consists  of  a  solid  piston 
(plunger),  working  through  a  stuffing-box  in  a 
long  cylinder  standing  upon  a  special  casting 
known  as  the  H-piece.  This  is  so  called  because 
it  is  made  up  of  two  parallel  cylinders,  like  the 

FIG.  522. 


FIG.  520. 


FIG.  519. 


FIG.  521. 


s 

DDD 
ODD 
ODD 

con 

ODD 
ODD 


two  upright  limbs  of  the  tetter  H,  which  are 
connected  by  a  horizontal  pipe,  like  the  cross-bar. 
The  H-piece  is  often  faulty  from  presenting  a 
path  with  very  sudden  turns ;  all  angles  should 
be  rounded  off,  so  as  to  make  the  passage  of  the 
water  as  easy  as  possible.  The  H-piece  has  a 
valve  immediately  above  the  wind-bore  or  suction- 
pipe.  In  the  figure  the  wind-bore  is  flat-ended 
because  it  is  resting  in  a  cistern.  Above  the 


452  ORE  AND  STONE-MINING. 

H-piece  comes  the  door-piece  with  another  valve,  and  then  a 
series  of  pipes,  the  "  column,"  generally  of  cast  iron,  but  some- 
times, as  already  stated,  of  wrought  iron. 

The  action  is  easily  understood.  When  the  plunger  is  moved 
upwards,  water  is  drawn  in  by  the  wind-bore,  and  when  the 
plunger  descends,  the  bottom  clack  closes,  the  top  clack  opens, 
and  the  water  is  forced  up  into  the  column.  The  plunger  is 
a  hollow  cylinder  of  cast  iron,  accurately  turned  outside.  Usually 
one  end  of  a  wooden  rod  is  passed  through  it  and  wedged  tightly 
at  the  bottom,  and  the  other  end  is  attached  to  the  main  rod  by 
staples  and  glands,  being  kept  at  a  proper  distance  from  it  by  a 
piece  of  timber. 

The  plunger  pump  can  claim  superiority  over  the  lifting  pump 
for  several  reasons  :  it  is  less  likely  to  get  out  of  order,  and,  if  it 
does  begin  to  fail,  its  shortcomings  are  more  quickly  perceived  and 
more  easily  remedied.  The  first  advantage  is  almost  self-evident ; 
one  need  only  picture  the  leathern  rim  of  the  bucket  rubbing 
against  the  sides  of  the  working  barrel,  and  the  solid  plunger 
sliding  up  and  down  through  the  stuffing  box,  to  feel  convinced 
that  it  is  more  difficult  to  keep  the  former  tight  than  the  latter. 
Practical  experience  confirms  this  a  priori  reasoning.  "When  the 
water  contains  sand  in  suspension,  the  bucket  wears  out  rapidly 
and  has  to  be  changed  at  frequent  intervals;  consequently  it 
must  be  performing  much  of  its  work  in  an  inefficient  manner. 
Incipient  faults  of  the  bucket  causing  but  a  slight  diminution  in 
the  quantity  of  water  raised  are  likely  to  pass  unnoticed,  whereas 
a  leaky  stuffing-box  is  at  once  detected.  This  latter  defect  can  be 
speedily  cured  by  the  man  in  charge  of  the  pumps  (pitman),  who 
has  simply  to  take  a  spanner  and  tighten  up  a  few  nuts,  whilst 
changing  a  bucket  of  an  ordinary  lifting  pump  involves  the  with- 
drawal of  the  whole  length  of  rods  to  which  it  is  attached,  an 
operation  causing  some  trouble  and  requiring  time.  Lastly,  the 
efficient  manner  in  which  the  plunger  does  its  work  renders  it 
suitable  for  higher  lifts  than  the  bucket. 

In  the  majority  of  cases  a  drawing  lift  is  fixed  at  the  bottom, 
because  it  can  be  lengthened  as  the  shaft  is  deepened,  a  process 
going  on  continually  in  vein-mining,  and  further  because  it  can 
be  worked  with  less  f  ear  of  a  complete  break-down  than  a  plunger, 
if  the  water  rises  in  the  mine  and  submerges  the  working 
parts.  This  bottom  pump  lifts  the  water  into  a  cistern  in  which 
stands  the  wind-bore  of  the  plunger  pump  (Fig.  522),  and  the 
remainder  of  the  pumping  is  done  in  stages.  The  first  plunger 
forces  the  water  up  a  column  into  another  cistern,  some  60  or 
more  yards  higher,  where  a  second  plunger  continues  the  work 
and  raises  the  water  into  a  third  cistern,  and  so  on  until  it 
reaches  the  surface  or  the  adit. 

Pumping  is  usually  done  in  stages  because  it  is  not  always 
easy  to  keep  the  joints  tight  when  the  pressure  of  the  water  i& 


DRAINAGE. 


453 


very  great.  The  difficulty  is  nowadays  far  less  than  it  was  for- 
merly, and  columns  are  made  even  as  much  as  600  metres  (656 
yards)  in  height  vertically. 

The  subject  of  pumps  would  not  be  complete  without  a  few 
words  upon  valves.  The  common  leather  clacks  used  in  some 
buckets  have  already  been  briefly  mentioned.  The  valves  of 
pumps  may  be  divided  into  two  classes — viz.,  clacks  and  metal 
valves. 

Figs.  523  and  524  represent  a  simple  valve  called  the  Hake's 
mouth  valve.  It  consists  of  the  seat,  slightly  conical  below  so  as 
to  fit  into  the  proper  recess  in  a  casting,  such  as  the  H  -piece  or 
clack-piece,  and  the  moving  flap  made  of  a  piece  of  strong  leather 
between  two  plates  of  iron,  held  flrmly  together  by  copper  rivets. 
The  flap  is  attached  to  the  "  tail "  of  the  seat  by  bolts,  and  the 
pliable  leather  not  only  makes  the  hinge,  but  ensures  a  water-tight 
contact. 


FIG.  523. 


FIG.  525. 


FIG.  527. 


FIG.  524. 


FIG.  526. 


FIG.  528 


In  the  butterfly  valve  (Figs.  525  and  526)  there  are  two  semi- 
circular lids  or  flaps.  In  a  clack  known  as  "  Jan  Ham's  clack," 
the  two  lids  are  hinged  on  the  outside  and  look  towards  each  other 
instead  of  from  one  another. 

A  valve  which  has  given  great  satisfaction  in  Cornwall  is 
known  as  Trelease's  valve  (Figs. 5  2  7  and  528).  Its  peculiarity  is  the 
great  freedom  of  motion  given  to  it  by  its  hinge.  The  seat  has 
two  upright  "  risers  "  with  slots  in  which  the  pin  of  the  clack  can 
move  up  and  down.  The  valve  is  of  metal  with  a  sheet  of  leather 
I  riveted  on  for  making  it  water-tight.  It  will  be  readily  under- 
stood that,  as  the  leather  is  not  playing  the  part  of  a  hinge,  a 
valve  of  this  description  will  last  longer  than  those  described 
previously  ;  it  can  also  be  used  with  a  bucket. 

If  the  water  is  corrosive,  as  too  frequently  happens  in  mines, 
the  seat  and  the  valve  are  made  of  brass,  gun-metal,  or  bronze, 
and  a  recess  is  made  in  the  circumference  of  the  seat  for  the 
insertion  of  wood,  which  will  last  longer  for  the  "  beat "  than 
metal. 

Teague's  noiseless  valve  (Figs.  529  to  531)  is  made  by  inserting 


454 


ORE  AND  STONE-MINING. 


FIG.  529. 


FIG.  530. 


a  small  valve  into  the  flap  of  a  Hake's  mouth  valve.     It  is  said  to 
remove  entirely  the  concussion  met  with  in  large  pumps. 

Among  the  metallic  valves  the  most  important  is  the  double- 
beat  valve,  the  object  of  which  is  to  afford  as 
great  a  waterway  as  possible  with  a  small  rise 
of  the  valve.  A  double- beat  valve  may  be  briefly 
described  as  a  bell  with  a  large  hole  at  the  top, 
and  surfaces  of  contact  at  top  and  bottom  ;  when 
the  bell  is  raised  by  the  pressure  underneath, 
there  are  two  passages  by  which  the  water  can 
escape,  one  sideways,  all  round  the  bottom,  and 
one  upwards,  through  the  top.  It  was  invented 
originally  for  steam  engines,  and  long  after- 
wards was  applied  to  pumps.  The  valve 
shown  in  Figs.  532  to  534  consists  of  a  shell  a, 
connected  to  a  ring  i  by  radial  arms  c.  The 
letters  b  indicate  strengthening  ribs  on  the  out- 
side of  the  shell;  they  are  inclined  a  little  so 
that  the  stream  of  water  passing  through  the 
valve  may  cause  it  to  turn  slightly  each  time  it 
is  opened,  and  beat  in  a  different  position.  This 
ensures  even  wear  and  keeps  the  valve  water-tight. 
The  two  "  beats,"  that  is  to  say  the  two  surfaces  of  contact,  marked 
n  and  m,  are  rings  of  white  metal,  gutta-percha,  or  india-rubber  fitted 
in  grooves  in  the  two  seats  q  and  I;  r  is  a  guide  for  the  central 
ring  i  which  is  bushed  with  brass,  indicated  by  the  black  line ; 
o  and  p  are  radial  arms  on  which  slides  the  brass  bushing  of  the 
lower  ring  of  the  shell,  and  they  are  stayed  by  the  cylindrical  piece 


FIG.  531. 


FIG.  532. 


533- 


FIG.  534. 


s  and  the  ring  I.  The  rise  of  the  valve  is  limited  by^,  which  is  kept 
in  its  place  by  the  screw  e,  held  by  a  nut  in  the  cross-bar  d  ;  h  h 
is  the  chamber  in  which  the  valve  works.  Eig.  533  shows  the  valve 
open,  and  Eig.  534  is  an  elevation  of  the  valve  and  lower  seat, 
which  will  greatly  assist  in  making  its  mode  of  action  plain. 

The  number  of  beats  is  sometimes  increased  to  three  or  four. 

Bittinger  Pump. — The  Rittinger  pump  is  an  important 
variety  which  has  been  introduced  on  the  Continent,  for  reme- 
dying one  of  the  defects  of  the  ordinary  pumping  plant — viz., 


DRAINAGE.  455 

its  intermittent  action.  The  Cornish  engine  makes  a  sudden 
start,  the  "outdoor"  end  of  the  beam  goes  up,  and  with  it 
the  main  rod  and  the  plungers  ;  then  comes  a  pause,  and  all 
this  time  no  useful  work  of  raising  water  is  being  done.  Lastly, 
the  beam  and  the  main  rod  slowly  descend  and  the  plungers 
force  up  water.  The  actual  work  of  pumping  proper  is  accom- 
plished in  a  short  part  of  the  time  occupied  by  a  double  stroke. 
It  is  evident  that  a  smaller  engine  doing  work  continuously 
would  be  just  as  effective  as  the  large  one  acting  at  intervals. 

The  Rittinger  pump  (Figs.  535  and  536)  may  be  described  briefly 
as  a  differential  pump,  with  two  hollow  plungers,  one  fixed  and 
the  other  moving.  A  B  is  the  moving  part  of  the  pump,  consisting 
of  the  air-chamber  and  plunger  case  A,  the  hollow  plunger  B, 
and  the  quadruple-beat  valve  C.  It  is  drawn  up  and  down  by  the 
side  rods  D  D.  E  is  the  top  of  a  lower  section  of  the  rising 
main,  and  F  a  large  pipe  constituting  a  cistern.  G  is  a  valve 
at  the  bottom  of  the  plunger  case  H.  At  the  top  there  is  the 
second  hollow  plunger  I,  which  is  fixed,  working  through  a 
stuffing-box  in  A,  and  K  is  the  rising  main;  L  is  the  space 
for  air. 

When  the  moving  part  A  B  ascends  C  closes,  and  water  is  drawn 
up  into  I  and  K  ;  at  the  same  time  G  opens,  and  water  makes  its 
way  through  it  into  H.  When  A  B  descends  the  space  above  G  is 
diminished,  C  rises,  and  water  flows  into  A.  The  descent  of  A  B 
increases  the  space  above  the  valve  C,  but  as  the  plunger  B  is 
larger  than  the  plunger  I,  more  water  flows  into  A  than  it  can 
accommodate ;  consequently  some  of  it  must  ascend  through  K. 
The  amount  so  passing  will  depend  upon  the  relative  diameters 
of  the  two  plungers.  In  considering  the  quantity  pumped  during 
each  stroke,  it  must  be  observed  that  the  two  hollow  plungers 
displace  just  as  much  as  if  they  were  solid,  because  they  are 
always  filled  with  water ;  therefore  the  effective  area  of  each  is : 

/outside  diameter\2  ( 

Let  P  and  p  represent  these  areas  of  the  large  and  the  small 
plunger  respectively  and  L  the  length  of  the  stroke.  When  A  B 
makes  its  up-stroke,  a  quantity  of  water  equal  to  L  p  is  drawn  up 
into  K ;  during  the  down-stroke  the  amount  rising  into  K  is  equal 
to  the  difference  of  the  volumes  displaced  by  the  two  plungers — • 
viz.,  L  P-Lj9  or  L  (P-p).  If  it  is  desired  that  the  delivery 
shall  be  the  same  at  each  stroke,  whether  up  or  down,  we  must 
make 

Lp  =  L(P-.p). 
From  this  we  get, 

=  LP. 

=• 


456  ORE  AND  STONE-MINING. 

In  other  words,  the  area  of  the  section  of  the  small  plunger  must  be 
FIG.  535.  FIG.  536. 


OD 


one-half  that  of  the  large  one.    This  is  carried  out  in  practice  ;  in 
one  of  the  large  pumps  at  Mansfeld  the  diameter  of  the  large 


DRAINAGE.  457 

plunger  is  0*90  m.  (2ft.  njin.),  and  that  of  the  small  one 
0*64  m.  (2ft.  i in.).  The  areas  are  therefore  0^63  sq.  m.  and 
0*32  sq.  m. 

It  is  possible  to  dispense  with  the  main,  rod  altogether  by 
interposing  the  rising  main,  between  the  two  plungers,  one  being 
placed  at  the  bottom  of  the  shaft  and  the  other  at  the  top ;  but 
this  plan  does  not  meet  with  general  approval,  because,  although 
it  saves  the  cost  of  a  main  rod,  it  subjects  a  long  column  of  pipes 
alternately  to  tension  and  compression,  with  the  result  of  trouble 
from  leakages. 

(d)  Accessory  Arrangements :  Counterbalances,  Catches, 
&c. 

Counterbalances. — The  weight  of  the  main  rod,  with  its 
strapping  plates  or  other  connections,  is  generally  greater  than  is 
required  for  the  purpose  of  forcing  up  the  column  of  water  in 
the  pumps,  and  overcoming  the  friction  of  the  various  parts  of  the 

FIG.  537- 


machinery.  It  becomes  necessary,  therefore,  both  in  order  to 
avoid  useless  waste  of  power  in  lifting  the  main  rod,  and  to  prevent 
its  descending  with  too  great  a  speed,  to  counterbalance  so  much  of 
the  weight  as  is  not  actually  employed  in  doing  useful  work.  The 
commonest  form  of  counterbalance  is  a  "  bob"  such  as  shown  in 
Fig.  537.  It  is  a  beam  d  d  working  upon  pivots  (gudgeons)  k,  which 
lie  in  brasses ;  the  end  e,  called  the  nose  of  the  bob,  is  attached  to 
the  main  rod  by  a  long  connecting  rod,  whilst  g  is  a  box  which 
is  filled,  or  partly  filled,  with  old  iron  or  stones.  The  beam  is 
stiffened  by  the  upright  "  king  post "  a,  and  the  straps  b  c ;  ffjf 
are  staples  and  glands  fastening  the  casting  m  to  the  beam,  and  i 
is  the  "  bishop's  head  "  at  the  top  of  the  "  king  post."  Cast-iron 
beams,  precisely  like  the  beams  of  an  engine,  fulfil  the  same  office 
at  some  mines,  and  the  counterbalance  is  a  huge  piece  of  cast-iron 
(Fig.  544).  There  is  usually  a  "  balance  bob  "  at  the  surface,  and 
others  are  fixed  at  intervals  in  large  recesses  (bob-plats)  cut  out 
in  the  side  of  the  shaft. 

West  and  Darlington  have  introduced  the  counterbalance  shown 


458 


ORE  AND  STONE-MINING. 


in  Eig.  538 ;  a  is  a  plunger  attached  to  the  main  rod  of  the  pump 
by  a  set-off,  b  is  a  horizontal  pipe  connecting  the  two  plunger-cases, 
e  is  the  second  plunger  carrying  the  box  ft  which  is  weighted  as 
required  ;  g  g  are  its  guides.  The  slight  losses  of  water  are  made 
up  from  the  pipe  h,  which  communicates  with  a  cistern,  or,  when 
this  method  cannot  be  used,  a  little  plunger  j  will  draw  up  and 
force  in  the  necessary  supply.  Eig.  539  represents  the  same  kind 
of  counterpoise  applied  to  an  inclined  shaft. 


FIG.  538. 


FIG.  539. 


Hydraulic  counterpoises  have  been  found  to  be  the  most 
advantageous  with  the  huge  pumping  engines  of  1000  horse-power 
at  Mansfeld.  Probably  at  no  mines  in  the  world  has  the  question 
of  pumping  on  a  large  scale  been  more  carefully  studied  than  in 
that  district,*  and  the  engineers  have  come  to  the  conclusion  that 
it  is  advisable  to  make  their  wrought-iron  rods  act  invariably  by 
tension  and  never  by  compression.  They  therefore  have  a  weight 
at  the  end  of  the  rod,  and  the  rod  +  the  weight  must  be  so 
balanced  that  the  machine  has  no  work  but  that  of  raising  the 
water  and  overcoming  the  friction. 

*  Hammer,  "Die  neueren  Wasserbaltungen  beim  Mansfelder  Kupfer- 
schieferbergbau,"  Der  iv.  allgemeine  Deutsche  Bergmannstay,  in  Halle,  tiaale, 
1889.  Festbtricht  und  Verhandlungen,  p.  39. 


DRAINAGE. 


459 


FIG.  540. 


The  special  counterpoise  known  as  the  Bochkoltz  regenerator 
(Fig.  540  *)  is  added  to  some  pumps  for  the  purpose  of  aiding  the 
main  rod  on  beginning  its  downward  course,  when  it  has  not  only 
to  overcome  the  weight  of  the  water  in  the  column,  but  also  to 
open  the  clacks.  The  regenerator  has  been  applied  on  the 
assumption  that  at  this  moment  there  is  an  excess  of  work,  because 
the  pressure  of  the  water  on  the  under  side  of  the  valve  is  acting 
upon  a  smaller  area  than  the  water  on  the  upper  side,  the 
difference  being  the  area  of  the  beat.  Bochkoltz  attaches  a  very 
heavy  weight  to  the  counterpoise  at  the  surface,  at  right  angles 
to  the  beam.  If  the  balance  beam  in  Fig.  537  is  reversed,  so 
that  the  king-post  hangs  down- 
wards, and  if  a  weight  is  fixed  to 
the  bishop's  head,  you  have  a 
Bochkoltz  regenerator.  In  Fig.  540 
A  is  the  cylinder  of  a  Bull  engine ; 
B,  the  piston-rod ;  0,  the  main 
rod  of  the  pumps ;  D,  the  beam ; 
E,  a  weighted  box ;  F,  a  weighted 
box. 

Suppose  that  the  plunger  has 
finished  its  up-stroke.  The  Boch- 
koltz weight  now  hangs  like  a  pen- 
dulum about  to  begin  an  oscillation, 
and  in  descending  under  the  action 
of  gravity  it  assists  the  main  rod 
in  its  work  ;  as  it  approaches  a 
vertical  position  its  influence  is 
lessened,  and  finally  it  creates  a 
resistance  when  it  has  to  be  raised 
again.  It  does  good  at  the  begin- 
ning of  the  stroke  by  helping  the 
weight  of  the  rods,  and  it  does  good 
at  the  end  of  the  stroke  by  dimin- 
ishing the  velocity  gradually,  and  by 
bringing  the  pumping  machinery  to  a  standstill  without  a  shock. 
The  idea  that  there  is  an  excess  of  pressure  upon  the  clacks  at 
first  is  not  borne  out  by  experiments,  but  the  regenerator  has 
the  advantage  of  enabling  the  engine  to  be  started  at  a  higher 
speed  than  would  be  safe  without  it ;  the  mean  speed  is  thus 
increased,  and  the  engine  is  able  to  make  a  larger  number  of 
strokes  safely  per  minute. 

The  same  effect  as  that  of  the  Bochkoltz  regenerator  is 
obtained  in  a  very  simple  manner  by  M.  Rossigneux,f  who  gives 
the  beam  a  curved  bearing  surface  which  rolls  upon  a  plane 

*  Gallon,  Lectures  on  Mining,  Atlas,  vol.  ii.,  plate  Ixxxii. 
f  Exposition    Universelle   de    1889.      Notice  sur  la  KociiU  Anonyme  des 
Houilleres  de  Montr ambert  et  de  la  Utraudiere,  Saint-Etienne,  1889,  p.  52. 


460 


ORE  AND  STONE-MINING. 


(Figs.  541  and  542).  By  this  device  the  ratio  of  the  lengths  of  the 
two  arms  of  the  beams  is  always  varying  :  at  the  commencement 
of  the  down-stroke,  the  weight  of  the  main  rod  is  acting  with  a 
long  leverage  compared  with  that  of  the  counterpoise,  at  the  end 
of  the  stroke  the  conditions  are  reversed.  The  excess  of  pressure 
due  to  the  length  of  leverage  accelerates  the  motion  at  first,  and 
then,  as  this  leverage  diminishes,  the  weight  of  the  counterpoise 
becomes  more  and  more  felt  and  the  rod  is  stopped  gradually. 
The  same  effects  occur  during  the  up-stroke  of  the  main  rod. 
The  counterpoise  begins  by  accelerating  the  motion,  then  its 

FIG.  541. 


I    O  5  IO  15  2O  25  3O  FEET 


influence  is  less  and  less  felt  until  the  rod  stops.  Hossigneux's 
system  can  be  applied  to  any  existing  beam  with  comparatively  little 
expense ;  indeed  it  was  first  adopted  in  the  case  of  a  Cornish 
pumping  engine,  which  was  becoming  incapable  of  coping  with  an 
additional  influx  of  water,  owing  to  the  deepening  of  the  shaft. 
The  variable  counterpoise  rendered  it  possible  to  increase  the 
number  of  strokes  per  minute  with  safety,  and  so  enabled  the 
engine  to  do  more  work. 

Catches. — Provision  must  be  made  for  a  possible  breakage  of 
the  main  rod,  which  might  have  very  disastrous  results  for  the 
mine.  If  such  an  accident  happened  without  any  of  the  ordinary 
safeguards,  the  beam  would  come  down  with  great  force  and 
play  havoc  in  the  engine-house,  whilst  the  main  rod  dropping  in 
the  shaft  would  be  sure  to  do  damage  to  the  pumps. 


DRAINAGE. 


461 


FIG.  543. 


The  indoor  end  of  the  engine-beam  is  therefore  fitted  with  two 
projecting  arms  of  iron,  which  come  down  so  as  almost  to  touch 
two  strong  beams  at  every  stroke ;  if  a  breakage  happens,  they 
arrest  the  motion  of  the  engine-beam  before  it  has  had  time  to  do 
any  harm. 

Catches  are  also  fixed  in  the  shaft ;  they  are  strong  beams  of 
timber  c  c  (Fig.  543,  and  S,  Figs.  546  to  550), 
stretching  across  the  shaft  and  resting  in  good 
"  hitches,"  with  the  main  rod  a  working  between 
them.  The  wings  b  b  are  attached  to  the  main  rod 
by  straps  with  bolts  ("  staples  and  glands  "),  and  are 
so  adjusted  that  the  end  of  the  wing  almost  touches 
the  catch  at  the  end  of  each  down-stroke  of  the  rod. 
A  catch  of  this  kind  limits  the  possible  fall  of  the 
main  rod  to  the  length  of  the  stroke.  Catches 
placed  in  the  reverse  direction  are  also  useful  in 
supplementing  the  action  of  those  placed  upon  the 
beam  in  the  engine-house. 

Lastly,  it  must  be  recollected  that  large  pumping 
machinery  requires  tackle  capable  of  dealing  with 
the  heavy  weights  which  have  to  be  moved.  High 
shears  erected  at  the  top  of  the  pit  enable  pieces 
of  main  rod,  often  60  feet  in  length,  or  heavy 
H -pieces,  to  be  raised  and  lowered  by  means  of  a 
strong  hempen  or  steel  rope  worked  by  a  capstan 
moved  by  men,  or  better  by  a  drum  driven  by  a 
special  steam  engine. 

Hammer,  of  Mansfeld,  strongly  recommends  that  every  large 
pumping  engine  should  have  its  hydraulic  press  for  lifting  the 
beam,  when  changing  the  brasses  or  making  repairs,  the  slight 
extra  cost  being  amply  repaid  by  the  convenience  of  having  such 
an  appliance  always  ready  at  hand  ;  a  similar  press  for  raising  the 
heavy  fly-wheel,  if  used,  is  likewise  desirable. 

Pumping  Plant. — After  these  general  considerations  about 
pumps,  it  will  be  well  to  take  an  example  and  show  how  the  various 
parts  are  combined  in  order  to  carry  on  the  work  of  drainage. 
The  seven  Figures,  544  to  550,  illustrate  the  pumping  plant  at 
Shakemantle  Mine  in  the  Forest  of  Dean,  erected  by  Mr.  Thomas 
Smith,  the  manager,  to  whom  I  am  indebted  for  drawings,  and 
for  verbal  explanations  on  the  spot. 

The  shaft  is  oval,  22  feet  6  inches  by  n  feet  6  inches;  it  is 
"  steened  "  or  walled  from  top  to  bottom  with  sandstone,  the  stone 
being  set  in  ordinary  mortar  where  the  ground  is  dry,  and  in 
hydraulic  mortar  where  it  is  wet.  The  engine  is  a  low-pressure 
condensing  beam  engine,  with  a  yo-inch  (i'8o  m.)  cylinder  A, 
working,  with  a  i2-feet  (3*65  m.)  stroke,  the  heavy  fly-wheel  B, 
which  can  be  driven  at  as  slow  a  speed  as  three  revolutions  a 
minute.  The  main  rod  C  is  made  of  round  wrought  iron, 


462 


ORE  AND  STONE-MINING. 


FIG.  544. 


DRAINAGE. 


463 


8  inches  in  diameter  at  the  top, 
diminished  gradually  to  6  inches 
at  the  bottom.  D  is  a  beam  or 
"bob"  for  counterbalancing  so 
much  of  their  weight  as  is  not 
required  for  raising  the  water 
and  overcoming  friction.  There 
are  three  plungers,  each  27 
inches  (o'686  m.)  in  diameter, 
arranged  in  a  straight  line  with 
the  main  rod;  this  is  managed  by 
attaching  the  rod  to  a  cross-head 
E  (Fig.  547)  above  each  plunger, 
and  bringing  down  two  rods  F  F, 
one  on  each  side  of  the  H  -piece 
G,  to  a  lower  crosshead  E' — from 
which  the  main  rod  is  continued 
in  the  same  line  as  before.  The 
other  parts  are  as  follows:  H, 
plunger;  I,  cast-iron  supporting 
girder,  resting  upon  cast-iron 
shoes  built  into  the  sides  of  the 
shaft ;  J,  cistern  made  of  cast- 
iron  plates  bolted  together,  with 
the  joints  lined  with  cement,  and 
screwed  down  to  the  top  of  the 
column  K;  L  (Fig.  546),  spring 
to  steady  the  cistern ;  M,  hang- 
ing rods  which  have  the  same 
object ;  N,  windbore  in  the  cis- 
tern ;  O,  windbore  at  the  bottom 
of  the  shaft;  P,  the  door  for 
changing  the  bottom  valve  ;  Q, 
door  for  changing  the  top  valve ; 
R,  door  to  a  butterfly  valve, 
which  keeps  up  the  water  in  the 
column  while  the  valve  at  Q  is 
being  changed ;  S,  beams  across 
the  shaft  to  catch  the  rod  by  the 
cross-plates  T  in  case  of  a  break- 
age ;  TJ,  air-chamber. 

The  general  substitution  of 
iron  for  timber  effects  a  great 
economy  of  space  in  the  shaft ; 
the  fly-wheel,  which  prevents  any 
jerk  at  the  beginning  of  a  stroke, 
the  air-chambers,  and  the  ar- 
rangement of  the  plungers  in  the 


FIG.  543. 


464 


ORE  AND  STONE-MINING. 


FIG.  546. 


FIG.  547. 


U 


DRAINAGE. 


FIG.  548. 


FIG.  550. 


465 


FIG.  549. 


2  G 


466  ORE  AND  STONE-MINING. 

same  straight  line  as  the  rods,  all  aid  in  securing  a  freedom  from 
vibration  and  a  smoothness  of  motion  which  are  highly  conducive 
to  good  working.  The  result  is  that  the  dry  ness  of  the  shaft  and 
the  absence  of  noise  are  remarkable,  considering  the  large  quantity 
of  water  lifted — viz.,  nearly  1000  gallons  (4^  cubic  metres)  of 
water  per  minute  when  the  engine  is  going  at  the  speed  of  only  4 
strokes.  Some  idea  will  be  gained  of  the  massiveness  of  the  pit- 
work  by  mentioning  that  the  H -piece  alone  weighs  i6J  tons. 

Class  II. — Force  Pumps  worked  by  an  Engine  at  or 
near  the  bottom  of  the  Workings. — The  advantage  of  being 
able  to  dispense  with  the  ponderous  main  rod,  its  counterpoises, 
catches  and  succession  of  plungers,  is  only  too  obvious,  to  say 
nothing  of  economy  in  first  cost  and  more  speedy  erection ;  and 
this  second  class  of  pumping  machinery  is  being  more  and  more 
largely  used  where  circumstances  admit  of  its  adoption.  The 
objection  to  the  system  is  the  danger  of  the  machinery  being 
"drowned,"  and  so  rendered  useless,  by  any  unusual  influx  of 
water,  because  a  mishap  of  this  kind  would  involve  the  erection  of 
new  pumping  plant  for  draining  the  mine.  Where  the  engine  is 
at  the  surface,  such  a  contingency  as  the  drowning  or  partial 
drowning  of  the  workings  is  not  irremediable.  It  was  this  con- 
sideration which  led  the  authorities  at  Mansfeld  to  have  some  of 
their  engines  above  ground ;  for  in  that  district  huge  cavities  full 
of  water  (Schlotten)  may  be  encountered  unexpectedly  at  any 
moment  and  for  a  time  overpower  all  the  available  pumping  plant. 
On  the  other  hand,  at  Mechernich,  under  different  conditions,  the 
Cornish  engines  at  the  surface  have  been  given  up  and  replaced 
with  great  advantage  by  underground  machines. 

Underground  pumping  engines  are  divided,  according  to  the 
source  of  power,  into  those  worked  by  steam,  water,  compressed 
air,  electricity  or  by  petroleum  engines. 

Steam. — At  the  present  day  we  have  to  deal  mainly  with 
steam  engines  when  speaking  of  pumping  on  a  large  scale.  The 
steam  may  be  generated  above  or  below  ground;  if  the  boilers  are 
placed  above  ground,  great  care  has  to  be  taken  in  jacketing  the 
steam  pipe  which  comes  down  the  shaft,  in  order  to  prevent  loss 
of  heat  by  radiation  and  the  consequent  unprofitable  expenditure 
of  fuel. 

It  is  necessary  to  mention  two  types  of  engines  which  are  most 
commonly  met  with  :  (i)  horizontal  engines  without  fly-wheel ;  (2) 
horizontal  engines  with  fly-wheel.  The  engine  may  be  simple  or 
compound,  but  the  latter  class  is  naturally  more  in  repute. 

(i)  In  this  first  class  comes  the  differential  engine  of  Davey, 
which  has  been  already  described  in  speaking  of  engines  used  at 
the  surface.  Instead  of  working  the  pump  by  the  intermediary 
of  the  bob  and  the  main  rod,  the  plunger  is  attached  in  a  line 
with  the  piston-rod,  and  forces  the  water  up  the  column.  The 
height  to  which  such  a  column  can  be  taken  is  governed  by  the 


DRAINAGE.  467 

•strength  of  the  pipes,  and  the  difficulties  of  making  joints 
sufficiently  tight  to  resist  pressures  measured  by  hundreds  of 
pounds  to  the  square  inch.  At  La  Louviere  Mine  in  Belgium 
the  column  is  630  yards  (576  m.)  high,  and  probably  there  are 
few  much  higher  than  this  at  the  present  day ;  such  a  column 
means  a  pressure  at  the  bottom  of  55*6  atmospheres,  or  817  pounds 
to  the  square  inch. 

Davey  provides  for  the  possible  drowning  of  the  lower  part  of  a 
mine,  through  an  inrush  or  unusual  influx  of  water,  by  placing 
his  main  engine  at  a  sufficient  height  above  the  bottom  to  render 
it  practically  safe  from  flooding ;  he  lifts  the  water  to  it  from 
the  bottom  by  means  of  an  auxiliary  pump.  This  latter  pump  is 
worked  by  hydraulic  power  transmitted"  by  pipes,  and  it  will 
perform  its  work  efficiently  even  if  it  is  drowned. 

There  are  many  of  these  direct-acting  pumps  without  fly-wheels 
in  the  market,  such  as  those  of  Knowles,  Tangye  and  Worthing  - 
ton,  but  want  of  space  prevents  my  describing  them. 

(2)  Fly-wheels  are  added  in  order  to  secure  that  smooth  and 
xegular  action  which  is  so  conducive  to  the  efficiency  of  machinery. 
Figs.  551  and  552  give  a  general  idea  of  one  of  the  under- 
ground pumping  engines  at  Mansfeld.  It  is  a  horizontal  com- 
pound engine  working  four  plungers  or  rams.  A  is  the  high- 
pressure  cylinder,  2  feet  n^-  inches  (900  mm.)  in  diameter,  B  the 
low-pressure  cylinder,  3  feet  9^  inches  (1*150  m.)  in  diameter,  C 
is  the  fly-wheel,  D  and  E  are  crossheads  connected  by  the  rods  F 
and  G,  and  similarly  H  and  I  are  crossheads  connected  by  the 
rods  J  and  K;  L  M  N  O  are  the  four  rams,  each  9!  inches  (0*25  m.) 
in  diameter,  having  the  same  stroke  as  the  pistons  of  the  en- 
gine, 4  feet  ij  inches  (1*250  m.).  P  P'  and  Q  Q'  are  delivery 
pipes  leading  to  a  main  delivery  pipe  R,  which  goes  to  the  rising 
main  in  the  shaft.  When  the  engine  is  working  at  the  rate  of 
30  revolutions  per  minute,  it  is  calculated  that  it  raises  1540 
gallons  (7  cubic  metres)  of  water  per  minute  to  a  total  height  of 
•612  feet  (i86'5  m.).  The  specific  gravity  of  the  water  is  1*2. 

This  type  of  pumping  engine  is  likewise  found  satisfactory  on 
all  points  at  Mechernich.  When  a  Cornish  engine  was  employed 
the  consumption  of  coal  was  4  kil.  per  effective  horse-power, 
measured  in  water  actually  raised,  now  it  is  only  2  'i  kil.  A  strong 
door  is  erected  outside  the  pump-room,  which  can  be  closed  so  as 
to  shut  it  off  for  some  time  even  when  the  water  rises  considerably. 

Riedler  bases  his  system  of  constructing  pumps  upon  some  of 
the  same  considerations  as  those  which  guided  Burckhardt  and 
Weiss  in  improving  air-compressors;  he  works  his  valves  by 
gearing,  and  so  secures  the  advantage  of  driving  his  pumps  at  very 
much  higher  speeds  than  are  possible  with  valves  which  open  and 
<jlose  of  themselves.  As  in  the  case  of  the  air-compressor,  this 
rapidity  of  stroke  enables  a  smaller  machine  to  be  employed  for 
•doing  a  given  amount  of  work. 


468 


ORE  AND  STONE-MINING, 


Pulsometer. — The  pulsometer  (Fig.  553)  is  a  form  of  pump 
used  at  mines  for  heights  not  exceeding  70  or  80  feet,  and  usually 
only  for  temporary  purposes.  The  steam  arriving  by  the  pipe  e 
presses  directly  upon  the  surface  of  the  water  in  a  chamber  a. 


t/) 


and  drives  it  through  an  opening  d  and  a  valve  into  the  rising 
main.  When  the  discharge  is  all  but  complete,  the  steam 
passing  with  the  water  through  d  creates  a  disturbance  and  in 
consequence  is  condensed ;  this  causes  a  ball-valve  /  at  the 
top  of  the  adjoining  chamber  to  pass  over  and  shut  off 
the  entry  of  the  steam.  The  steam  now  enters  the  adjoining 


DRAINAGE. 


469 


chamber,  and,  acting  as  before,  forces  its  contents  up  the 
rising  main.  In  the  meantime  the  steam  in  the  first 
chamber  is  being  condensed,  and  its  place  is  taken  by  water 
drawn  up  the  suction  pipe 
c;  b  is  an  air-chamber, 
g  g  are  the  suction-valves, 
and  h  h  stops  which  arrest 
them.  The  action  is  re- 
peated first  in  one  chamber 
and  then  in  the  other,  so 
that  a  continuous  stream 
of  water  is  forced  up. 

The  pulsometer  will 
pump  muddy  or'  gritty 
water,  it  occupies  little 
space,  is  very  portable,  and 
is  easily  fixed;  in  fact,  it 
may  be  even  hung  in  a 
.shaft  from  a  chain ;  it  dis- 
poses of  its  own  exhaust 
.steam,  it  requires  no  special 
attendant,  and  so  long  as  it 
is  supplied  with  steam  it 
will  go  on  working.  Under 
these  circumstances  it  is 
evident  that  the  pulso- 
meter is  capable  of  ren- 
dering very  useful  services 
to  the  miner. 

Water. — Some  success- 
ful applications  of  the 
method  of  working  pumps  underground  by  hydraulic  power 
transmitted  from  the  surface  have  been  carried  out  at  mines  in 
Scotland  and  on  the  Comstock  lode  in  Nevada.*  A  horizontal 
•engine  erected  at  the  surface  (Fig.  554)  works  two  rams  d  d',  and 
these  force  water  down  the  two  pipes  E  E'  to  the  underground 
rams  D  D  D'  D' ;  g  g  are  valves  through  which  water  is  supplied 
to  the  pressure-pipes  from  cisterns.  The  plungers  of  D  I)  and 
D'  D'  are  attached  to  a  cross-head  C  which  carries  the  two  pump- 
ing plungers  A  and  B.  The  ram  d  forces  water  into  the  two 
power  rams  D,  and  the  ram  d'  into  the  two  opposite  rams  D'. 
If  water  is  being  driven  down  by  d,  the  cross-head  C  will  be 
moved  towards  B ;  the  mine-water  will  be  forced  up  by  its 

*  Joseph  Moore,  u  On  Hydraulic  Machinery  for  Deep  Mining,"  Trans. 
Inst.  Eng.  and  Shipbuilders  in  Scotland,  vol.  xxv.,  1882,  p.  177.  E.  T. 
Moore,  "On  an  Improved  Arrangement  for  Working  Underground  Pumps 
by  Means  of  Hydraulic  Pressure,"  Trans.  Hin.  Inst.  Scotland,  vol.  v.,  1884, 
p.  290.  "Moore's  Hydraulic  Pump,"  Engineering,  vol.  xli.,  1886,  p.- 126. 


470 


ORE  AND  STONE-MINING. 


plunger,  and  sucked  up  by  A.  At  the  same  time  the  power 
water  in  D'  D'  will  be  driven  back  a  little  way,  ready  to  move 
in  the  opposite  direction  as  soon  as  d'  makes  its  stroke.  The 
underground  pump  thus  follows  precisely  the  movement  of  the 
engine  at  the  surface ;  the  pressure  in  the  transmitting  pipes  is 
not  less  than  1000  Ibs.  per  square  inch,  and  this  enables  small 
pipes  to  be  employed.  The  pumps  may  be  placed  as  desired,  and 
the  system  has  been  used  not  only  for  permanent  work,  but  alsa 
in  the  case  of  sinking  a  shaft. 

Compressed  Air  and  Electricity. — Pumps  driven  by  com- 
pressed air  or  electricity  are  very  convenient  in  situations  where 
steam  power  is  forbidden  by  the  conditions  of  the  workings, 
such  as  were  set  forth  at  length  in  a  previous  chapter.  The 

FIG.  554. 


/%ffi^////ff%/^ 


pumps  worked  by  electricity  mostly  take  the  form  of  three- 
rams,  driven  from  a  common  crank  shaft,  fixed  upon  the  same 
bed-plate  as  the  motor.  The  high  speed  of  the  motor  is  reduced 
by  gearing,  so  as  to  give  the  crank  shaft  a  number  of  revolu- 
tions per  minute  suitable  for  pumping.  The  choice  between 
compressed  air  or  electricity  will  depend  in  many  cases  upon 
what  plant  is  in  use  at  the  mine  for  other  purposes.  If  com- 
pressed air  is  being  generated  for  boring  machines  or  haulage, 
it  is  only  natural  to  make  use  of  it  instead  of  putting  up  a 
special  engine  to  drive  a  dynamo. 

Where  compressed  air  is  laid  on  in  a  mine,  it  is  easy  to  employ  it 
for  working  a  Knowles,  Cameron,  Tangye,  or  other  direct-acting 
pump ;  but  water  may  be  raised  in  a  still  simpler  fashion  by  the 
Pohle  pump,  which  is  giving  satisfaction  at  mines  in  Colorado,* 
and  in  supplying  factories  near  New  York.  It  is  merely  a  pipe 

*  E.  Le  Neve  Foster,  M.S.  Notes,  and  Browne  and  Behr,  "  Dr.  Pohle's- 
Air-lift  Pump,"  Trans.  Technical  Soc.  Pac.  Coast,  vol.  vii.,  Feb.  1890. 


DRAINAGE. 


FIG.  555. 


full  of  water  with  a  jet  of  air  at  the  bottom.  A  B  (Fig.  555)  is  the 
so-called  well,  a  piece  of  ordinary  wrought-iron  pipe  3  inches  in 
diameter ;  it  is  connected  by  a  bend  to  the  T-piece  C,  through  the 
bottom  of  which  passes  a  piece  of  J-inch  pipe,  bringing  in  air  at 
a  pressure  varying  from  30  to  70  Ibs.  per  square  inch.  The 
water-column  proper  is  made  of 
2 -inch  pipe,  D  E  F,  which  turns 
over  at  the  top  and  discharges 
into  another  well  G.  The  height 
from  the  bottom  of  C  to  the  top 
of  the  water  in  G  is  100  feet, 
but  as  the  level  of  the  top  of  the 
water  in  the  well  A  B  is  50  feet 
above  C,  the  actual  lift  effected 
by  the  air  is  only  50  feet.  By  a 
succession  of  such  lifts  the  water 
can  be  raised  to  any  desired 
height.  This  pump  commends 
itself  by  its  simplicity,  by  the 
ease  and  cheapness  with  which 
it  can  be  constructed,  and  by  the 
absence  of  any  expense  for  keep- 
ing it  in  order. 

For  some  time  past  Messrs. 
Evans  and  Veitch  have  been 
raising  water  at  Cae  Coch  Mine, 
in  Carnarvonshire,  by  the  direct 
action  of  compressed  air.  Their 
latest  pump  (Figs.  556  and  557) 
consists  of  two  forcing  chambers 
A  and  A7  submerged  in  water, 
each  provided  with  an  inlet  valve, 
B  and  B',  and  a  discharge  valve, 
C  and  C',  which  lead  into  a  com- 
mon rising  main  D.  Compressed 
air,  brought  into  the  two  cham- 
bers alternately  by  the  pipes  E 
and  E',  presses  upon  the  surface 
of  the  water  and  forces  it  up 
the  pipe  F  or  F  into  D.  The 

compressed  air  is  turned  alternately  into  E  or  E'  by  the  action 
of  a  valve  worked  by  the  independent  cylinder  G,  placed  in  any 
convenient  situation.  H  (Fig.  557)  is  a  pipe  bringing  air  from 
the  compressor  to  the  valve-chest  I,  with  its  piston  valve  J.  In 
the  position  shown,  E'  is  receiving  air  by  the  port  e',  whilst  E 
communicates  with  atmosphere  through  e.  The  valve  J  is  moved 
by  the  tappets  K  K3,  which  are  struck  by  the  crosshead  L, 
attached  to  the  rod  which  is  common  to  the  two  pistons  M  and  N. 


472 


ORE  AND  STONE-MINING. 


O  is  the  piston-valve  admitting  compressed  air  into  the  cylinder 
G  from  the  pipe  P ;  it  is  worked  by  the  tappets  K1  K2.  The 
cylinder  Q  is  full  of  oil,  which  can  be  drawn  from  one  side  to  the 

other  by  the   piston 

FIG.  556.  N  if  the  cock  R  is 

open.  The  travel  of 
the  piston  in  N  can 
be  regulated  by  the 
cock ;  the  more  nearly 
it  is  closed  the  slower 
will  the  piston  move. 
In  order  to  make 
sure  that  the  valve  0 
shall  not  stick  partly 
open,  two  sets  of 
holes,  sl  s2  s3  s*,  are 
provided,  and  when 
the  piston  passes,  for 
instance,  between  sl 
and  s2,  the  oil  can 
make  its  way  round 
without  going 
through  the  cock ; 
the  decrease  in  the 
resistance  quickens 
the  stroke  and  makes 
it  sharp  and  decisive 
at  the  end. 

With  the  object  of 
economising  the  com- 
pressed air,  the  in- 
ventors propose  in 
some  cases  to  take 
the  exhaust  from  the 
pipes  E  and  E'  direct 
to  the  compressing 
cylinder,  allow  it  to 
expand  behind  the 
piston  and  so  return 
a  little  of  the  power 
expended  in  compres- 
sing it.  The  two 
chambers  A  A'  may 
very  well  be  joined  together  in  one  casting,  as  they  are  in  the 
pulsometer,  and  they  may  of  course  be  far  more  deeply  submerged 
than  is  shown  in  the  figure. 

Duty. — In  accounts  of  pumping  engines  the  student  will  often 
meet  with  the  expression  "  duty."     This  term  means  the  number 


FIG.  557- 


DRAINAGE.  473 

of  pounds  of  water  raised  i  foot  high  by  the  consumption  of  1 1 2 
pounds  of  coal ;  as  used  by  Watt  the  quantity  of  coal  was  i 
bushel,  reckoned  at  94  pounds.  In  the  early  part  of  this  century 
much  interest  was  evinced  in  Cornwall  with  reference  to  the 
work  done  by  the  various  pumping  engines  of  the  county,  and 
there  was  great  rivalry  among  the  engineers,  who  vied  with  each 
other  in  getting  the  highest  duty  from  the  engines  and  the 
machinery  under  their  charge.  The  consequence  of  various  im- 
provements in  engines  and  boilers  resulted  in  reaching  duties 
which  approached  and  even  for  short  periods  exceeded  100  millions. 

The  performance  of  each  engine  was  ascertained  by  attaching 
a  counter  to  the  beam,  which  registered  the  number  of  its 
oscillations;  the  counter  was  kept  under  lock  and  key  and 
examined  monthly  by  an  independent  observer.  The  number  of 
strokes  made  by  the  engine  was  thus  known.  The  work  done 
in  pumping  was  calculated  from  the  number  and  depth  of  the 
various  lifts,  the  size  of  the  plungers  and  the  stroke  of  the 
engine,  and  a  record  was  kept  of  the  amount  of  coal  consumed. 
With  these  data  the  duty  could  be  determined,  and  the  figures 
were  published  every  month.  Nowadays  this  spirit  of  emulation 
among  Cornish  agents  seems  to  have  disappeared,  few  engines 
are  "  reported,"  and  the  duties  recorded  do  not  as  a  rule  exceed 
50,  60,  or  70  millions. 

Though  the  knowledge  of  the  duty  is  valuable  in  indicating  the 
general  efficiency  of  the  pumping  plant,  the  mere  determination 
of  this  figure  does  not  give  all  the  information  that  ought  to  be 
in  the  hands  of  the  mining  engineer,  for  it  does  not  tell  him 
where  he  can  and  should  make  improvements.  When  he  finds  a 
difference  in  the  respective  "  duties  "  of  two  pumping  engines  at  his 
mine,  there  is  nothing  to  tell  him  whether  the  fault  of  the  less  effec- 
tive plant  lies  in  the  coal,  the  engine,  the  boilers,  the  transmitting 
arrangements,  or  the  pumps  themselves.  It  is  important,  there- 
fore, that  the  engines  should  be  indicated,  and  that  the  indicated 
horse-power  of  the  engine  should  be  compared  with  the  actual 
useful  effect  in  water  raised.  Hammer  *  has  found  that  the  power 
consumed  in  some  cases  by  the  mere  friction  of  the  guides  in  the 
shaft  is  as  much  as  24  to  30  per  cent,  of  the  total  power  given  out 
by  the  engine.  Too  much  importance  cannot,  therefore,  be  paid 
to  the  accurate  fixing  of  the  main  rod  and  its  guides. 

Slip. — In  calculating  the  delivery  of  a  plunger  it  is  usual  to 
make  an  allowance  for  the  running  back  of  some  of  the  water 
through  the  valve,  from  its  not  closing  completely  when  the 
down-stroke  commences.  This  is  what  is  known  as  "slip,  "and 
it  is  sometimes  estimated  at  20  per  cent,  of  the  actual  delivery, 
though  in  reality  scarcely  appreciable  in  the  best  pumps,  f 

Co-operative  Pumping. — Owing  to  the  subdivision  of  pro- 

*   Op.  cit.,  p.  45. 

t  Kankine,  A  Manual  of  Civil  Engineering,  London,  1883,  p.  735. 


474  ORE  AND  STONE-MINING. 

perty  in  this  country  and  want  of  appreciation  of  the  importance 
of  the  subject,  too  little  attention  has  been  paid  to  what  may  be 
called  co-operative  drainage.  One  successful  application  of  the 
principle,  the  Halkyn  Tunnel,  has  been  mentioned,  and  another 
instance  deserves  to  be  noticed,  though  in  this  case  the  mineral  is 
coal.  The  South  Staffordshire  Mines  Drainage  Commission  is  a 
corporate  body  constituted  under  several  Acts  of  Parliament,* 
passed  during  the  last  twenty  years,  for  the  purpose  of 
facilitating  the  drainage  of  mines  in  parts  of  South  Staffordshire 
and  East  Worcestershire.  The  Commissioners  have  power  under 
their  Acts  to  levy  a  rate  of  yd.  for  every  ton  of  coal,  slack  and 
ironstone  raised  within  a  certain  district,  and  yl.  for  every  ton  of 
fireclay  and  limestone.  In  order  to  have  some  check  upon  the 
statements  of  output  made  by  the  mine-owners,  the  Commissioners 
have  by  their  last  Act  obtained  the  right  of  placing  inspectors 
to  report  upon  the  quantities  of  minerals  raised. 

It  is  not  merely  by  erecting  pumping  engines  of  the  most 
approved  and  economical  types  at  suitable  centres  that  the 
Commissioners  have  done  good  work;  but  the  results  of  their 
labours  in  preventing  surface  water  from  finding  its  way  down 
are  well  worth  recording.  To  use  their  own  words,  "  By  carrying 
out  surface  drainage  works,  such  as  rendering  water-tight  the 
canals  and  streams  throughout  the  district,  draining  large  ponds 
of  accumulated  water  on  the  surface,  diverting  or  enlarging  such 
watercourses  as  caused  overflows  in  seasons  of  great  rainfalls,  and 
such  other  works  as  were  necessary  to  reduce  the  volume  of 
water  flowing  into  the  mines  by  percolation  to  a  minimum 
amount,"  they  reduced  "the  average  quantity  of  water  which  has 
to  be  pumped  in  the  Tipton  district  every  24  hours  from 
22,705,000  gallons  in  1875  to  11,643,000  in  1882,  a. decrease  of 
nearly  50  per  cent."  When  considering  this  remarkable  and 
very  satisfactory  result,  the  special  circumstances  of  the  district 
must  not  be  left  out  of  sight.  In  no  mining  district  in  this 
country  are  the  effects  of  subsidence  more  apparent  than  they 
are  in  places  where  the  thick  coal  of  South  Staffordshire  has  been 
worked  underneath,  and  therefore  the  cracked  and  fissured 
overlying  strata  were  ready  to  exaggerate  the  evils  of  percolation ; 
but  at  the  same  time  this  very  fact  rendered  the  application  of  a 
remedy  all  the  more  difficult. 

According  to  the  Annual  Report  published  in  i892,t  27^- 
tons  of  water  were  raised  for  every  ton  of  mineral  extracted  from 
the  mines,  and  at  a  cost,  so  far  as  the  Commissioners'  engines  were 
concerned,  of  o'i8  of  a  penny,  or  less  than  one  farthing,  per  ton 
of  water  raised. 

*  36  &  37  Viet.,  c.  150;  41  &42  Viet.,  c.  81  ;  45  &  46  Viet.,  c.  131  ;  54  & 
55  Viet.,  c.  135. 
t  Colliery  Guardian,  vol.  Ixiv.,  1892,  p.  648. 


(     475     ) 


CHAPTER  X. 
VENTILATION. 

Atmosphere  of  mines — Causes  of  pollution  of  the  air  in  mines — Natural 
ventilation — Artificial  ventilation  by  furnaces  and  by  machines — Fans 
— Testing  for  fire-damp — Determination  of  carbonic  acid  and  oxygen 
— Anemometers — Water-gauge — Efficiency  of  fans — Friction. 

ATMOSPHERE  OF  MINES. — The  composition  of  the  air 
of  the  atmosphere  is  about  one-fifth  by  volume  of  oxygen  and 
four-fifths  of  nitrogen,  with  a  little  carbonic  acid  gas ;  more 
exactly,  the  standard  amount  of  oxygen  may  be  taken  at  20-9  per 
cent.,  and  that  of  the  carbonic  acid  gas  at  0*03  to  0*04  per 
cent. 

The  atmosphere  of  mines  is  subject  to  various  influences  which 
are  constantly  rendering  it  less  fit  for  supporting  life  ;  not  only 
do  noxious  gases  escape  from  the  rocks  into  the  underground 
excavations,  but  the  very  agents  themselves  employed  in  the 
execution  of  the  work  pollute  the  air  considerably. 

Gases  sometimes  given  off  in  mines  are :  carbonic  acid,  marsh 
gas,  nitrogen,  sulphuretted  hydrogen,  and  the  vapours  of  mercury 
and  volatile  hydro-carbons.  . 

Carbonic  Acid  is  known  to  exude  from  coal,  and  is  also  met 
with  in  beds  and  veins  of  other  minerals.  It  is  common,  for 
instance,  in  the  Sicilian  sulphur  mines,*  where  it  is  called  by  the 
miners  rinchiusu. 

At  the  lead  mines  of  Pontgibaud,  in  Central  France,  it  is  so 
abundant  that  special  fans  have  to  be  provided  for  getting  rid  of 
it ;  very  distinct  issues  of  this  gas  may  be  observed  at  the  Foxdale 
lead  mines  in  the  Isle  of  Man.f  Emanations  of  this  gas  from 
"  lochs  "  or  "  vugs  "  have  been  reported  to  me  as  occurring  at 
Great  Laxey  mine,  in  the  Isle  of  Man,  and  at  Pennerly  and 
Roman  Gravel  mines  in  Shropshire;  however,  in  none  of 
these,  as  far  as  I  am  aware,  has  the  issue  been  so  strong  or  so 
lasting  as  at  Foxdale.  In  the  Alston  Moor  district,  according 
to  Mr.  Wallace,  the  quantity  of  carbonic  acid  discharged  both 

*  Baldacci,  Descrizione  geologica  dell  'Isola  di  Sicilia,  Kome,  1886,  p.  362. 
f  C.  Le  Neve  Foster,  "  An  Emanation  of  Carbonic  Acid  at  Foxdale  Mine, 
in  the  Isle  of  Man,"  Trans.  It.  Oeol.  Soc.  Cormvalt,  vol.  x.,  p.  175. 


476  ORE  AND  STONE-MINING. 

by  the  veins  and  the  enclosing  rocks  is  occasionally  very  con- 
siderable.* 

Carbonic  acid  is  thought  by  Blountf  to  exist  sometimes  in 
the  liquid  state  in  minute  pores  or  fissures  of  chalcopyrite,  and 
he  ascribes  the  decrepitation  of  certain  kinds  of  pyrites,  when 
heated,  to  its  presence.  No  doubt  such  pyrites  would  be 
capable  of  giving  off  the  gas  slowly  at  the  ordinary  temperatures 
of  mines. 

The  hot  springs  and  their  accompanying  gases  at  Sulphur 
Bank  minej  in  California  are  very  remarkable.  An  analysis 
of  the  gas  gave  : 

Carbon  dioxide 89-34 

Hydrogen  sulphide        .         .         .         .  0^23 

Marsh-gas      ......  7*94 

Nitrogen 2*49 


1 00 '00 

Some  of  the  emanations  contained  ammonia,  and  the  tempera- 
ture of  the  water  escaping  from  cracks  in  one  of  the  levels  was 
.176°  F.  (80°  C.),  or  more  than  the  highest  temperature  observed 
at  mines  on  the  Comstock  lode. 

Marsh-gas  is  the  main  constituent  of  fire-damp,  which  is  by  no 
means  confined  to  coal  mines,  as  some  might  suppose.  In  this 
country  it  is  found  in  small  quantities  in  the  stratified  ironstone 
of  the  Cleveland  district,  and  also  in  the  Cheshire  salt  mines.  As 
minute  bubbles  of  the  gas  may  be  noticed  in  the  brine  which  is 
pumped  up  from  bore-holes  near  Middlesbrough,  it  is  probable 
that  it  accompanies  rock-salt  in  that  region  also.  Mill  Close 
lead  mine,§  in  Derbyshire,  was  the  scene  of  a  disastrous  explosion 
of  fire-damp,  some  years  ago,  by  which  five  men  were  killed,  and 
in  1884  two  men  were  burnt  by  the  gas  taking  fire  in  a  level  at 
Holway  Consols  Mine,  ||  near  Holywell  in  Flintshire,  where  a  fatal 
accident  had  happened  from  an  explosion  fifteen  years  previously. 

At  the  famous  Van  Mine  ^f  in  Montgomeryshire,  fire-damp  was 
found  at  the  adit,  and  at  nearly  every  level  below,  while  "  tapping  " 
the  lode ;  in  other  words,  while  making  the  first  drivages  in  it 
The  miners  regard  it  as  a  sure  harbinger  of  lead  ore. 

Even  the  tin  mines  of  Cornwall  are  not  entirely  free  from  fire- 
damp. Inflammable  gas  was  given  off  by  the  bed  of  stream-tin 

*  The  Laws  which  Regulate  the  Deposition  of  Lead  Ore  in  Veins,  London, 
1861,  p.  130. 

t  "  Decrepitations  in  Samples  of  so-called  Explosive  Pyrites,"  Jour.  Chem. 
Hoc.,  vol.  xlvii.,  1885,  p.  593  ;  and  Min.  Jour.  vol.  lv.,  1885,  p.  1297. 

%  Becker,  "Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope," 
Mon.  V.  S.  Geol.  Survey,  vol.  xiii.,  Washington,  1888,  p.  258. 

§  Reports  of  H.M.  Inspectors  of  Mines  for  the  Year  1887,  p.  316. 

||  Ibid.,  1884,  p.  204. 

1"  C.  Le  Neve  Foster,  "  Notes  on  the  Van  Mine,"  Trans.  R.  Geol  Soc. 
Cornwall,  vol.  x.,  p.  36. 


VENTILATION.  477 

worked  under  the  mud  of  Restronguet  Creek,*  near  Falmouth,  in 
1873,  and  three  comparatively  slight  explosions  took  place  at  Ding 
Dong  Mine,f  near  Penzance,  about  the  year  1860,  on  re-opening 
a  level  which  had  long  been  under  water ;  but  in  this  case,  as  in 
some  others  which  will  be  mentioned,  the  gas  seems  to  have  been 
formed  by  the  decomposition  of  the  timber  supports  of  the  level. 

Turning  to  the  Continent,  it  is  not  surprising  to  meet  with 
large  quantities  of  inflammable  gas  in  oil-wells  and  in  ozokerite 
mines.  The  work  of  sinking  oil-wells  in  Roumaniaj  is  much 
impeded  by  emanations  of  marsh-gas ;  artificial  ventilation  becomes 
necessary  when  a  depth  of  50  feet  (15  m.)  is  reached,  and  the  first 
thing  the  men  have  to  do  in  the  morning  is  to  work  the  fan  for 
three  hours.  Even  then  the  sinker  cannot  stay  down  more  than 
about  two  hours  at  a  time,  and  when  the  bottom  of  the  shaft  is 
approaching  the  oil-bearing  stratum,  he  cannot  stay  more  than  a 
quarter  of  an  hour.  He  is  always  fastened  to  a  rope,  and  two 
men  at  the  surface  are  constantly  on  the  alert  to  draw  him  up  at 
once,  if  he  makes  the  ]east  sign  by  pulling  it.  The  sinker  is 
sometimes  quite  giddy  when  he  reaches  the  surface. 

The  conditions  at  the  petroleum  wells  of  Burma  are  still  more 
unfavourable.  There  is  so  much  gas  that  breathing  is  difficult, 
and  the  longest  time  a  young  and  strong  man  can  stay  below 
without  becoming  unconscious  is  290  seconds.  Often  a  man  can 
work  only  i  or  2  minutes ;  he  can  be  lowered  to  a  depth  of  200 
feet  in  J  minute  and  raised  in  i  to  ij  minutes;  in  the  upper 
parts  of  a  well,  where  there  is  no  gas  or  only  a  little,  he  can 
remain  below  much  longer.  § 

There  are  probably  few,  if  any,  mines  more  fiery  than  the 
ozokerite  pits  of  Boryslaw.  Explosions  have  often  happened,  and 
the  mines  have  to  be  worked  with  safety  lamps.  However,  it  i& 
likely  that  both  here,  and  in  the  oil  regions,  the  inflammability  of 
the  atmosphere  is  due  not  only  to  marsh-gas,  but  also  to 
the  vapour  of  volatile  hydrocarbons  given  off  by  the  crude 
petroleum,  which  maybe  seen  on  the  floor  of  the  workings.  Mere 
marsh-gas  alone  would  not  account  for  the  spirituous  taste  of 
the  air  and  the  slight  smarting  of  the  eyes  which  are  noticed 
underground.  The  effect  of  the  gases  is  to  produce  all  sorts  of 
hallucinations  and  make  the  men  wander  in  their  talk. 

The  sulphur  rock  of  Sicily  ||  emits  fire-damp  very  frequently, 

*  Taylor,  "  Description  of  the  Tin  Stream  Works  in  Restronguet  Creek, 
near  Truro,"  Proc.  Inst.  Mech.  Eng.,  1873,  p.  159. 

t  Higgs,  "  Notice  of  an  Accumulation  of  Carburetted  Hydrogen,  or 
1  Fire-damp,'  in  the  Ding  Dong  Mine,"  Trans.  R.  GeoL  8oc.  Cornwall,  vol.  ix., 
p.  34. 

J  Exposition  Universelle  de  Paris  en  1889 :  Notice  sur  la  Roumanie,  Paris, 
1889,  p.  60. 

§  Noetling,  "  Oil-field  of  Twingoung  and  Berne,  Burma,"  Bee.  GeoL 
Survey  India,  vol.  xxii.,  1889,  p.  98. 

||  Baldacci,  op.  cit.,  p.  362. 


478  ORE  AND  STONE-MINING. 

and  the  official  list  of  disastrous  explosions  shows  that  it  is  an 
enemy  not  to  be  despised  by  the  miner.  The  gas  fills  cavities 
existing  in  the  bed  of  mineral,  and  also  comes  out  of  the 
bituminous  shale  of  the  partings ;  it  is  called  antimonio  by  the 
men. 

Marsh-gas  accompanies  salt  on  the  Continent,  as  it  does  in 
England ;  a  jet  of  the  gas,  which  has  been  piped  off  from  a  blower 
and  now  serves  for  illuminating  purposes,  may  be  seen  constantly 
burning  in  the  salt  mine  at  Bex  in  Switzerland.  Small  explo- 
sions have  taken  place  in  the  Stassfurt  district. 

Several  men  were  killed  by  an  explosion  of  fire-damp  in  a 
tunnel  in  the  Oxford  Clay,*  which  was  in  course  of  being  driven 
under  the  Col  de  Cabres,  on  the  boundary  of  the  Departments 
Drome  and  Isere  in  France,  during  the  year  1887,  and  the  gas  is 
given  off  in  such  quantities  in  the  clay  pits  at  Klingenberg  on  the 
Main  f  that  safety  lamps  have  to  be  used  by  the  miners. 

Inflammable  gas  is  not  noticed  in  working  the  copper  shale 
itself  at  Mansfeld,  though  the  large  amount  of  bituminous  matter 
which  the  seam  contains  might  make  one  fear  it  would  be  trouble- 
some ;  a  little  has  been  met  with  in  driving  levels  in  some  of  the 
surrounding  rocks  and  especially  in  the  gypsum. 

Large  quantities  have  been  observed  in  Silver  Islet  mine,! 
Lake  Superior,  where  several  explosions  occurred  ;  and  at  Duncan 
mine.§  Port  Arthur,  upon  the  same  lake,  vugs  were  noticed  to 
contain  hydrocarbon  gas  under  great  pressure. 

Becker  records  emissions  of  inflammable  gas  at  several  of  the 
quicksilver  mines  in  California.  [|  Inflammable  gas,  probably 
marsh-gas,  caused  a  disastrous  explosion  at  the  Bell  tunnel  of  the 
New  Idria  Mine,  and  marsh-gas  escapes  at  the  ^ICtna  Mine.  At 
the  Phoenix  Mine  inflammable  gas  issues  from  cracks  in  the  150 
.and  3oo-foot  levels,  the  chief  component  being  marsh-gas,  as 
shown  by  the  following  analysis  : 

Carbonic  anhydride  .  .  .  .  074 

Marsh-gas     .        .  ,  .  .'  .  61^49 

Nitrogen       ,    -.-;  .  .-  ,  .  31 '44 

Oxygen         .        .  .  .  .  .  6-33 

lOO'OO 

Treloar  ^f  gives  an  account  of  an  issue  of  inflammable  gas  at  the 
Morro  Yelhogold  mine  in  Brazil;  it  took  fire  while  the  men  were 
boring  a  hole. 

*   Comptes  JRendus,  Soc.  2nd.  Min.,  August  1887. 

t  Colliery  Guardian,  vol.  Ivi.,  1888,  p.  192. 

£  Macfarlane,  "Silver  Islet,"  Trans.  Amer.  Inst.  M.E.,vol.  viii.,  1880, 
p.  241  ;  Eng.  Min.  Jour.,  vol.  xxxiv.,  1882,  p.  322. 

§   Trans.  Amer.  Inst.  M.E.,  vol.  xv.,  1887,  p.  673. 

||  "  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope,"  Mon.  U.  S. 
Geol.  Survey,  Washington,  1888,  pp.  308  and  373. 

11  Trans.  R>  Geol.  Soc.  Cornwall,  vol.  vii.  p.  345. 


VENTILATION. 


479 


Fire-damp  is  frequently  encountered  in  the  old  workings  of 
alluvial  mines  in  the  goldfields  of  Victoria  ;  *  in  some  instances  it 
is  doubtless  due  to  the  decomposition  of  prop  timber,  as  at  Ding 
Dong,  and  in  others  to  the  gradual  alteration  of  driftwood  or 
organic  matter  in  the  alluvial  beds  themselves.  A  serious  accident, 
caused  by  a  fire-damp  explosion,  is  recorded  as  having  injured  two 
men  at  the  Try-again  Company's  mine,  El  Dorado,  in  the  Beech- 
worth  Mining  district.! 

Nitrogen,  if  given  off  in  small  quantities,  is  likely  to  pass  un- 
noticed by  the  miner ;  but  it  makes  its  presence  felt  occasionally. 
Miners  in  Strinesdale  tunnel,  near  Stockport,  have  been  troubled 
by  the  escape  of  nitrogen  from  fissures  in  the  rock.  It  has  been 
ascertained  by  analysis  that  the  gas  consists  of  92  volumes  of 
nitrogen,  8  volumes  of  oxygen,  and  a  trace  of  carbonic  acid.  It 
came  from  openings  in  the  roof,  sides  and  floor,  and  was  strong 
enough,  in  one  case,  to  put  out  a  candle  18  inches  away  from  the 
fissure.  The  men  became  sick  and  dizzy,  and  their  limbs  were 
semi-paralysed.  On  some  occasions  the  fissures  drew  the  candle- 
flame  in,  instead  of  blowing  gas  out,  suggesting  a  communication 
with  old  workings  in  the  neighbourhood. 

The  highly  poisonous  sulphuretted  hydrogen  is  of  frequent 
occurrence  in  the  Sicilian  sulphur  mines,  where  the  water  is 
often  saturated  with  it.  At  the  3ooo-foot  level  of  the  Corn- 
stock  J  lode,  the  water  is  charged  with  carbonic  acid  and 
sulphuretted  hydrogen,  and  has  a  temperature  of  i7o°F. 
(76*7°  C.).  A  blower  of  the  gas,  met  with  in  a  copper  mine  at 
Ducktown,§  Tennessee,  was  strong  enough  to  drive  the  men  away 
from  their  work  for  a  time.  Two  bad  accidents  took  place  in  sink- 
ing a  shaft  at  Stassf  urt,  through  rock-salt,  from  sudden  irruptions 
of  the  gas :  on  one  occasion  eight  persons,  and  on  the  other  seven 
persons,  were  stifled.  Various  fatalities  are  ascribed  to  sul- 
phuretted hydrogen  at  the  ozokerite  mines  of  Boryslaw,  but  here 
it  is  thought  that  the  gas  was  generated  by  some  process  of  de- 
composition in  old  workings,  which  were  "  holed  into  "  by  the 
miners.  Sulphuretted  hydrogen  produced  in  a  somewhat  similar 
way  is  supposed  to  have  been  the  cause  of  a  death  at  a  mine  on 
the  Gympie  goldfield,  Queensland.)) 

As  a  natural  emanation  in  mines,  sulphurous  acid  is  very 
rare,  but  Becker  has  noticed  a  pungent  gas  near  the  i5o-foot 
level  at  the  Bedington  quicksilver  mine  in  California,  which 
he  considers  must  contain  both  it  and  sulphuretted  hydrogen.^" 

*  Report  o/  the  Chief  Inspector  of  Mines,  Victoria,  for  the  Year  1874,  Mel- 
bourne, 1875,  P-  9- 

t  Reports  of  the  Mining  Registrars  for  the  Quarter  ended  ^oth  September, 
1885,  Melbourne,  p.  15. 

J  Becker,  op.  cit.,  p.  339. 

§  Phillips,  Ore  Deposits,  1884,  London,  p.  574. 

||  Fryar,  Gases  in  Mines,  Brisbane,  1890,  p.  8. 

IT  Op.  cit.,  p.  287. 


.  /-»_  OF 


480  ORE  AND  STONE-MINING. 

Sulphurous  acid  is  generated  in  the  underground  fires  of  sulphur 
mines  in  Sicily,  and  some  will  be  formed  in  other  cases  of  under- 
ground fires,  if  the  rock  contains  iron  pyrites. 

Small  quantities  of  mercurial  vapour  are  stated  to  be  found  in 
quicksilver  mines,  and  to  be  the  reason  of  their  unhealthiness  ;  but 
one  may  also  suggest  that  constant  contact  with  cinnabar,  inhaling 
the  dust  of  the  mineral,  and  allowing  some  to  enter  the  stomach 
from  eating  with  dirty  hands,  may  possibly  account  for  all  the 
symptoms  observed,  without  having  recourse  to  the  theory  that 
the  vapour  is  present  in  the  atmosphere  of  the  mine. 

Artificial  Pollution  of  the  Air  in  Mines. — The  pollution 
of  the  air  is  not  due  solely  to  gases  introduced  naturally  from 
the  surrounding  rocks  ;  various  other  causes  combine  to  render 
the  atmosphere  of  the  mine  unfit  for  life,  and  among  them  may 
be  mentioned  the  following  : 

1 .  Kespiration  of  the  persons  and  animals  in  the  pit  ;  exhalations  from 

their  skin,  and  emanations  from  excrement  left  underground. 

2.  Combustion  of  the  lamps  and  candles  used  for  lighting  the  working 

places. 

3.  Absorption  of  oxygen  by  pyrites  and  other  minerals. 

4.  Putrefaction  of  timber. 

5.  Explosion  of  gunpowder,  dynamite,  &c. 

6.  Stone  dust  from  boring. 

1,2.  Dr.  Angus  Smith*  reckons  that  two  men  working  eight 
hours,  and  using  J-  Ib.  of  candles  and  12  ozs.  of  gunpowder,  produce 
25*392  cubic  feet  of  carbonic  acid  at  70°  F. — viz.,  10*32  by 
breathing,  12*276  by  candles,  and  2*796  by  gunpowder. 

It  is  considered  by  some  medical  authorities  that  the  injurious 
effects  of  breathing  an  atmosphere  polluted  by  the  products 
of  respiration,  are  due  more  to  organic  matter  than  to  the 
small  proportion  of  carbonic  acid  it  contains.  The  quantity 
of  carbonic  acid  serves,  however,  as  an  index  of  the  amount  of 
organic  pollution,  and  when  the  air  of  a  room  is  found  to  contain 
0*06  per  cent,  by  volume  of  the  gas,  the  atmosphere  is  said  to  be 
unhealthy.  Care  should  be  taken  to  prevent  the  men  from 
habitually  using  the  workings  as  latrines,  and  to  apply  suitable 
disinfectants  if  the  rule  has  been  disobeyed. 

3.  Where  the  ventilation  is  sluggish,  the  absorption  of  oxygen 
by  pyrites,  or  by  ferruginous  minerals  passing  to  a  higher  state  of 
oxidation,  is  sometimes  very  marked. 

4.  More  important  is  the  foulness  of  the  underground   atmo- 
sphere produced  by  the  decay  of  the  timber  supports.     The  rapidity 
with   which   timber  rots  underground    in  certain  circumstances 
has  already  been  mentioned ;  the  practice  of  leaving  the  useless 
decaying  timber  to  infect  the  new  pieces  that  are  put  in,  turns  a 

*  Report  of  the  Commissioners  appointed  to  inquire  into  the  Condition  of 
all  Mines  in  Great  Britain  to  which  the  Provisions  of  the  Act  23  &  24  Viet. 
c.  151  do  not  apply,  Appendix  B.,  London,  1864,  p.  224. 


VENTILATION  481 

level  in  some  instances  into  a  hotbed  of  putrescent  matter,  offensive 
to  the  smell,  and  injurious  to  the  health  of  the  men.  Steel 
supports  should  be  welcomed,  if  only  for  ridding  mines  of  one 
source  of  pollution  of  the  atmosphere.  One  of  the  recommenda- 
tions of  the  Ventilation  Board  in  Victoria  is  that  all  the  bark 
should  be  removed  from  the  timber  before  it  is  sent  down  under- 
ground.* 

5.  The  nature  of  the  gases  and  solid  residues  produced  in 
blasting  has  been  already  explained  in  Chapter  IV.,  and  the 
statement  made  by  some  manufacturers  that  their  explosives 
produce  "no  noxious  fumes"  is  evidently  misleading.  In  the 
case  of  gunpowder,  we  have  the  smoke  made  up  of  fine  particles  of 
carbonate  and  sulphide  of  potassium  with  some  sulphur,  whilst 
the  explosive  force  has  been  due  to  the  formation  of  a  number 
of  invisible  gases,  especially  carbonic  acid,  carbonic  oxide  and 
nitrogen,  with  sulphuretted  hydrogen,  marsh-gas  and  hydrogen. 

Nitro-cotton  should  produce  nothing  by  its  explosion  but 
carbonic  acid,  carbonic  oxide,  hydrogen  and  nitrogen ;  and  nitro- 
glycerine only  carbonic  acid,  nitrogen,  and  oxygen.  But  when 
imperfectly  detonated  the  resultant  gases  are  more  noxious  ;  both 
explosives  generate  a  large  proportion  of  nitric  oxide,  and  carbonic 
oxide  is  liberated  in  considerable  quantity.  Dynamite  produces 
the  same  gases  as  nitro-glycerine,  but,  in  addition,  it  sends  into 
the  atmosphere,  in  a  very  finely  divided  state,  the  25  per  cent, 
of  infusorial  earth  which  it  contains.  Tonite,  made  from  gun- 
cotton  and  nitrate  of  barium,  produces  solid  carbonate  of 
barium,  and  the  quantity  is  estimated  to  be  55  per  cent,  of 
its  weight.f 

More  has  been  written  of  late  years  about  the  fumes  of  roburite 
than  about  those  of  any  other  explosive,  and  many  useful  observa- 
tions have  been  made  concerning  it.  After  a  close  examination  and 
an  analysis  of  the  fumes  produced  by  tonite  and  roburite,  Prof. 
Bedson  and  two  medical  menj  have  come  to  the  conclusion  that 
these  two  explosives  are  no  worse  for  the  health  of  the  miner 
than  gunpowder.  With  all  three  explosives  they  found  traces  of 
carbonic  oxide  in  the  air,  and  they  recommend  in  consequence 
that  an  interval  of  five  minutes  be  allowed  to  elapse  before  the 
men  return  to  their  working  places  after  firing.  The  ore-miner, 
in  studying  these  conclusions,  must  not  forget  that  the  recommend- 
ation is  made  in  the  case  of  working-places  which  were  being  swept 
out  by  air-currents  of  noo  to  5000  cubic  feet  per  minute — 
in  other  words,  the  moral  is,  that  if  no  such  currents  exist,  a 
longer  interval  should  be  given.  No  nitrobenzene  was  detected 

*  Report  of  the  Ventilation  of  Mines  Board,  Melbourne,  1888,  p.  x. 

*f  "  An  Investigation  as  to  whether  the  Fumes  produced  from  the  Use  of 
Roburite  and  Tonite  in  Coal  Mines  are  injurious  to  Health,"  Trans,  Fed. 
Inst.  Min.  Eng.,  vol.  ii.,  1891,  p.  380. 

J  Ibidem,  p.  388. 

2  H 


482  ORE  AND  STONE-MINING. 

in.  analysing  the  air  after  firing  roburite,  though  its  odour  was 
noticed  on  some  occasions. 

6.  We  now,  lastly,  come  to  stone  dust,  which  is  certainly  not 
the  least  noxious  of  the  impurities  of  the  atmosphere  breathed 
by  the  miner.  It  is  formed  in  the  process  of  boring  holes  for 
blasting,  by  the  shots  themselves  and  by  the  attrition  of  pieces 
of  rock  tumbling  about  during  the  ordinary  processes  of  mining. 
However,  it  is  probable  that  tbe  first  cause  is  the  one  from  which 
the  miner  is  most  likely  to  suffer  injury  :  when  he  is  boring  a  hole 
downwards  he  puts  in  water,  which  serves  the  double  purpose  of 
facilitating  his  work  and  of  preventing  any  dust  from  being 
formed;  but  when  he  bores  an  "upper"  by  hand,  water  is  not 
used,  and  even  where  machine  drills  are  employed,  it  is  not  always 
that  one  sees  a  jet  of  water  under  pressure  applied  to  the  bore- 
hole. The  result  is  that  the  atmosphere  of  an  "end  "  or  other 
working  place  may  contain  a  quantity  of  fine  particles  of  stone 
in  suspension,  which  are  inhaled  into  the  lungs,  and  irritate 
the  air-passages  ;  very  probably  they  are  the  principal  cause  of 
the  complaint  known  as  "  miner's  asthma "  or  "  miner's  con- 
sumption." 

Having  pointed  out  the  manner  in  which  the  atmosphere  of 
mines  is  constantly  being  deteriorated,  it  is  necessary  to  explain 
how  it  can  be  renewed,  and  so  kept  in  a  fit  state  for  the  workmen 
employed  underground. 

NATURAL  VENTILATION. — Two  systems  of  ventilation 
are  employed  in  mines — natural  and  artificial,  either  separately 
or  .combined.  Under  the  former,  currents  set  up  by  natural 
differences  of  temperature  change  the  air  of  the  workings  ;  under 
the  latter,  artificial  means  are  employed  to  bring  about  the  same 
result. 

The  principle  upon  which  natural  ventilation  depends  is  very 
easily  understood.  The  temperature  of  the  earth  increases  at  the 
rate  of  i°  F.  for  about  every  60  feet  of  depth,  and  this  natural 
heat  is  the  mainspring  in  creating  air-currents.  Suppose  a  very 
simple  case,  two  shafts  AB,  CD  (Fig.  558),  connected  by  a 
horizontal  level  B  D.  The  air  in  the  shafts  and  level,  warmed  by 
its  contact  with  the  sides  of  these  underground  passages,  gradually 
assumes  their  temperature,  which  will  be  usually  higher  or  lower 
than  that  of  the  external  atmosphere ;  the  problem  is  simply 
that  of  two  communicating  vases.  At  the  point  D  we  have  the 
pressure  due  to  the  weight  of  the  column  of  air  CD  +  the  weight 
of  the  atmosphere  at  C.  At  B  the  pressure  is  due  to  the  weight 
of  the  smaller  column  AB  +  the  weight  of  the  atmosphere  at  A. 

Draw  the  horizontal  lines  CF  and  AE  and  prolong  the  line  of 
the  shaft  AB  upwards  by  the  dotted  lines.  The  pressure  of 
the  atmosphere  at  F  and  C  is  the  same,  and  therefore  any 
difference  of  pressure  at  B  and  D  depends  upon  the  relative 
weights  of  the  columns  FB  and  CD  ;  but  AB  is  equal  to  ED,  so 


VENTILATION. 


483 


that  the  real  difference  depends  upon  the  weights  of  the  two  columns 
of  air  FA  outside  the  mine  and  CE  inside  the  mine.  In  this 
country  the  external  atmosphere  in  summer  is  often  hotter  than 
that  of  the  mine ;  therefore  the  column  CE  will  be  heavier  than 
the  column  FA.  The  column  CD  will  overcome  the  resistance 
presented  to  it  by  the  column  AB,  and  create  a  natural  current 
going  in  the  direction  CDBA.  In  winter  the  conditions  are 


FIG.  558. 


FIG.  559. 


reversed.  The  cold  external  column  FA  is  heavier  than  the 
comparatively  warm  internal  column  CE,  and  the  weight  of  the 
entire  column  FB  will  be  greater  than  that  of  the  column  CD. 
The  result  is  that  the  weight  of  the  column  FB  will  cause  motion 
in  the  direction  ABDC. 

A  still  simpler  case  is  one  of  common  occurrence  in  vein  mining 
(Fig.  559).  Let  AB  be  an  adit  driven  into  a  hill-side.  Draw 
CD  horizontal,  and  by  the  dotted  lines  AD  indicate  a  column 
of  air.  The  pressure  of  the  atmosphere  at  C  and  D  is  the  same ; 
the  pressure  at  A  is  that  of  the  column  of  air  AD  +  the  weight 
of  the  atmosphere  above  the  line  CD, 
whereas  at  B  one  has  the  same  constant  FIG.  560. 

weight  above  the  line  DC  together  with  N. 
the  column  CB.  If  AD  is  warmer  than 
BC,  there  will  be  a  greater  pressure  at 
B  than  at  A,  and  the  current  will  move 
in  the  direction  CBA  ;  if  AD  is  colder 
than  BC,  a  condition  of  things  happen- 
ing in  winter,  the  current  moves  in  pre- 
cisely the  opposite  way. 

Another  state  of  things  is  shown  in 
Fig.  560,  in  which  there  are  two  shafts 
of  unequal  depth  connected  by  an  in- 
clined passage  or  drift.  If  AE  is 
drawn  horizontal,  as  before,  at  the  level  of  the  higher  opening  to 
the  mine,  and  CF  parallel  to  it  at  the  level  of  the  lower  opening, 
the  air  in  the  bent  tube,  so  to  say,  CDB,  will  exactly  balance 
that  contained  in  the  vertical  shaft  FB,  and  for  motive  power  we 
have  to  depend  upon  the  difference  in  weight  of  the  two  columns 
AF  and  EC,  a  difference  depending  upon  their  relative  tempera- 


484  ORE  AND  STONE-MINING. 

tures.  Therefore  in  summer  we  get  a  current  travelling  in  the 
direction  ABDC,  whilst  in  winter  it  is  reversed. 

In  any  one  of  these  cases,  the  greater*  the  difference  in  tempera- 
ture, the  greater  will  be  the  velocity  of  the  ventilating  current.  In 
winter  the  ventilation  will  be  more  active  than  in  summer,  because 
there  will  be  more  difference  between  the  outside  and  inside  tem- 
peratures ;  and,  furthermore,  though  there  are  differences  between 
the  day  temperature  and  the  night  temperature,  still  the  tendency 
is  always  to  produce  a  current  in  the  same  direction.  In  summer 
the  nights  may  be  cold  though  the  days  are  hot,  and  therefore 
the  difference  in  temperature  between  the  air  of  the  mine  and 
that  of  the  surface  may  be  acting  in  two  opposite  ways  according 
to  the  period  of  the  day  or  night.  A  shaft  which  is  drawing  up, 
or  is  an  "upcast,"  during  the  heat  of  the  day  may  have  a 
descending  current,  or  be  a  "  downcast,"  in  the  cool  hours  of  the 
night,  and  practically  have  no  current  at  all  while  the  outside  and 
inside  temperatures  are  alike. 

There  is  not  only  this  objection  to  natural  ventilation  that  it 
may  vary  in  direction  during  the  course  of  the  twenty-four  hours, 
but  the  still  greater  objection  that  at  certain  seasons  of  the  year 
it  may  be  nil,  because  there  is  no  difference  in  temperature 
between  the  outside  and  inside  air  to  make  one  column  heavier 
than  the  other. 

The  creation  of  a  natural  air-current  is  not  due  solely  to  the 
difference  of  temperature  caused  by  the  natural  warmth  of  the 
rocks.  The  heat  engendered  by  the  respiration  of  the  men  and 
animals,  by  the  combustion  of  the  candles  or  lamps,  and,  lastly, 
by  the  explosives  is  also  a  factor  in  making  the  air  of  the  mine 
warmer  than  that  of  the  surface  and  so  setting  up  a  current. 
The  character  of  the  sides  of  the  shaft  itself  may  also  play  its  part. 
A  shaft  which  has  water  dropping  down  it,  either  from  natural 
springs  that  find  their  way  in,  or  from  slight  leaks  in  the  pumping 
plant,  will  naturally  become  the  downcast,  if  the  other  orifice  is  dry. 

The  strength  of  the  current  may  be  improved,  or  a  natural 
draught  created  where  none  existed  before,  by  building  a  chimney 
above  one  of  the  shafts,  and  so  producing  artificially  a  difference  of 
level  between  the  two  outlets.  The  direction  of  the  wind  may  also- 
turn  the  scale,  and  it  is  often  found  that  a  mine  is  better  ventilated 
with  some  prevailing  winds  than  with  others.  As  an  illustration 
of  an  effect  of  this  kind,  I  need  only  refer  to  smoky  chimneys, 
commonly  caused  by  the  wind  striking  some  natural  or  artificial 
obstruction,  which  directs  it  downwards  and  makes  it  overcome 
the  upward  draught  of  the  fire.  The  result  is  sometimes  so- 
marked  that  the  householder  can  tell  the  direction  of  the  wind, 
before  looking  out  of  doors,  by  noticing  which  of  his  chimneys 
is  giving  trouble.  With  some  mines  in  which  the  natural  current 
has  less  force  than  that  of  a  chimney,  it  is  not  to  be  wondered 
that  similar  occurrences  take  place. 


VENTILATION.  485 

When  speaking  of  natural  ventilation,  the  property  of  diffusion 
requires  a  word  of  comment.  This  property  is  one  by  which  two 
bodies  of  gas  placed  in  juxtaposition  with  one  another  gradually 
become  mixed,  even  if  the  lighter  occupies  the  higher  position. 
The  process  is  slow  compared  with  the  mixing  that  is  brought 
about  by  convection,  but  still  it  has  some  effect  in  causing  the  dis- 
persion of  noxious  fumes. 

In  the  examples  of  natural  ventilation  just  given,  it  has  been 
assumed  that  the  mine  has  two  orifices ;  but  many  workings,  at 
all  events  at  the  beginning,  have  only  one.  Let  us  take  the  three 
typical  cases  of  a  level,  a  shaft,  and  a  "  rise." 

Let  Fig.   561   represent  a  level  driven  a  short  way  into  the 

FIG.  561. 


side  of  a  hill.  How  is  the  atmosphere  of  the  "  end  "  renewed 
without  artificial  appliances?  On  entering  such  a  level  after 
blasting,  the  explanation  becomes  apparent :  a  current  of  powder 
smoke  is  seen  hugging  the  roof,  whilst  the  lower  half  of  the  level 
is  clear.  If  a  candle  is  set  up  on  the  floor,  its  flame  is  deflected 
inwards  or  towards  the  "  end."  The  heated  gases  from  the  ex- 
plosive, accompanied  by  air  warmed  by  breathing  and  the  combus- 
tion of  the  candles,  rise  as  much  as  they  can,  and  make  their  way 
out  by  the  upper  part  of  the  level,  while  their  place  is  taken  by  cold 
air  from  the  outside.  The  course  of  the  gentle  current  is  shown 
by  the  dotted  lines.  The  same  phenomenon  may  be  observed  in 

FIG.  562. 


a  cross  cut  driven  out  from  a  shaft.  This  explains  the  import- 
ance, or  indeed  the  necessity,  of  keeping  a  level  as  horizontal  as 
possible  if  it  is  being  ventilated  naturally.  Take  an  exaggerated 
case,  in  which  the  men  have  allowed  their  "  end  "  to  rise  consider- 
ably, as  shown  in  Fig.  562,  so  that  the  floor  of  the  working  place 
is  three  feet  above  a  horizontal  line  drawn  through  the  top  of  the 
mouth  of  the  tunnel.  Smoke  and  warm  gases  produced  in  the 
"  end  "  will  rise,  and,  finding  no  means  of  exit,  will  remain  in  the 
highest  part  until  they  cool  down  and  diffusion  has  had  time  to 
play  its  part. 

It  might  seem  at  first  sight  that  a  current  could  not  be  formed 
in  a  shaft  which  does  not  communicate  with  other  workings ;  but 


486 


ORE  AND  STONE-MINING. 


even  when  no  partition  of  any  kind  has  been  put  in,  the  sides 
of  the  pit  kept  cool  by  trickling  water  may  cause  the  air  to  form 
descending  currents,  whilst  in  the  centre  there  is  an  ascending 
current,  as  shown  in  the  diagram  (Fig.  563).  In  an  incline 
(Fig.  564)  the  ascent  of  the  warm  smoke  along  the  dry  roof 
and  the  influx  of  cold  air  along  the  floor  are  sometimes  very 
noticeable. 

When  the  working  place  is  a  "rise,"  it  is  evident  theoretically, 
and  still  plainer  practically,  that  the  warmth  of  the  foul  gases  at 
the  top  tends  to  keep  them  in  that  position,  and  that  the  evil 
must  increase  as  the  place  gets  hotter  (Fig.  565),  The  nature  of 
the  excavation  prevents  things  from  improving,  and  the  necessity 
for  artificial  ventilation  is  nowhere  more  apparent  than  in  a 
working  place  of  this  kind,  especially  if  the  space  is  confined. 
The  common  statement  that  carbonic  acid  collects  in  the  lowest 
part  of  the  workings  is  correct  only  in  cases  where  the  gas  is 


FIG.  563. 


FIG.  564. 


FIG.  565. 


LEVEL 


issuing  forth  from  the  rocks  and  sinks  down  like  water.  "Where 
it  is  produced  by  respiration,  candles,  lamps,  or  explosives,  it  is 
diffused  through  a  warmed  atmosphere,  ascends  with  it  and  does 
not  separate  from  the  other  gases.  The  consequence  is  that  a 
"  rise "  may  be  found  badly  ventilated  although  the  air  in  the 
level  below  is  fresh  and  pure. 

We  will  suppose  that  by  reason  of  the  difference  in  level  of  the 
two  main  orifices  of  the  mine,  a  trunk  ventilating  current  has 
been  established.  The  air  will  then  take  the  easiest  road  from 
one  shaft  to  the  other,  and  will  not  penetrate  into  any  other  parts 
of  the  workings  unless  compelled  to  do  so.  The  turning  of  the 
current  into  any  required  direction  is  effected  by  putting  in 
partitions  and  doors.  In  a  few  cases,  the  partition  serves  to  make 
a  clean  and  sharp  line  of  division  between  two  currents  which 
would  to  a  certain  extent  exist  naturally.  Thus,  we  have  seen 
that  when  the  length  of  a  level  is  not  great,  an  outward  current 
travels  along  its  roof,  and  an  inward  current  along  its  floor  (Fig. 
561) ;  between  the  two  there  is  a  dead  space  more  or  less  interfering 
with  both  currents  by  making  their  boundaries  ill-defined.  If  a 
horizontal  partition  of  planks  (air-sollar)  is  put  in  (Figs.  566  and 


VENTILATION. 


487 


567),  the  two  currents  are  kept  perfectly  distinct,  and  the 
natural  ventilation,  aided  in  this  way,  proceeds  in  a  much  more 
effective  manner;  the  level  can  therefore  be  driven  further 
without  having  recourse  to  machinery  for  creating  an  artificial 
current. 

A  common  problem  is  the  ventilation  of  the  far  end  of  a  drivage, 
AB  (Fig.  568),  provided  with  a  little  shaft,  CD,  which,  in 
winter,  naturally  creates  a  current  proceeding  from  A  to  D, 
and  ascending  at  once  to  C.  The  desired  effect  may  be  attained 
by  putting  in  an  air-sollar  DE,  which  compels  the  air  to  travel 
to  the  far  end  before  it  can  begin  its  ascent ;  another  plan 
consists  in  covering  the  bottom  of  the  shaft  by  a  platform 
(sottar),  and  carrying  a  pipe  from  it  all  the  way  along  the  roof 
of  the  level  to  the  "  end."  This  has,  of  course,  the  same  effect 
as  the  air-sollar,  but,  unless  the  pipe  is  large,  it  does  not  give 


FIG.  566.         FIG.  567. 


FIG.  568. 


so  much  area  for  the  current.  Pipes  have  the  advantage  that 
they  are  very  easily  put  in  and  that  they  can  be  used  again  and 
again.  These  methods  of  conducting  an  air  current  are  so 
self-evident,  that  I  should  not  have  mentioned  them,  were  it 
not  for  the  fact  that  some  mine  agents  appear  to  be  ignorant  of 
these  simple  expedients  for  improving  the  ventilation  of  their 
drivages. 

Where  the  level  is  wide  enough,  the  partition  may  be  placed 
vertically ;  it  is  then  called  a  brattice.  If  required  for  temporary 
purposes  it  may  be  made  of  canvas,  tarred  to  prevent  its  rotting 
(brattice  cloth).  More  lasting  and  effective  partitions  are  con- 
structed of  plank  or  of  brick. 

Any  close  vertical  partition  in  a  shaft  dividing  it  into  two 
separate  compartments  invariably  improves  matters,  when  the 
ventilation  of  a  sinking  is  becoming  sluggish ;  some  trifling  differ- 
ence in  the  condition  of  the  two  compartments  decides  which  is  to 
be  the  upcast  and  which  the  downcast.  Where  it  is  not  con- 
venient to  put  in  a  partition,  a  separate  air  compartment  may 
be  formed  by  fixing  a  large  pipe  against  one  side  of  the  shaft 
and  taking  it  up  30  or  40  feet  above  the  level  of  the  ground 


488 


ORE  AND  STONE-MINING. 


(Fig.  569);  in  this  manner  two  columns  of  unequal  height  are 
produced  with  the  desired  effect. 

If  a  rise  is  being  put  up,  or  if  stoping  is  being  carried  on 
without  any  winze,  there  is  no  difficulty  in  diverting  a  natural 
current  existing  in  the  level  below  and  making  it  serve  the  work- 
ing place.  All  that  is  required  is  to  block  the  passage  of  the 
current  along  the  level,  and  so  force  it  to  take  the  only  road  that 
lies  open  to  it.  In  Fig.  570,  AB  is  a  level,  and  C  the  top  of  a  rise, 
which  has  an  open  compartment  at  each  end ;  one  is  fitted  with 
ladders,  and  the  other  serves  as  a  shoot,  down  which  ore  or 
rubbish  can  be  thrown  into  the  level  below.  They  are  separated  by 
the  thick  partition  of  rubbish  piled  upon  a  platform  in  the  roof  of 
the  level  and  confined  by  timber  at  both  ends.  By  putting  a 


FIG.  569. 


FIG.  570. 


-? 


partition  in  the  level,  the  air  is  made  to  pass  up  one  end  of  the  rise, 
sweep  out  the  foul  air  produced  by  the  men,  candles  and  explosives 
at  C,  and  then  descend  into  the  level  once  more.  The  partition 
may  be  a  wooden  door  closing  tightly  against  its  frame,  or  a 
piece  of  brattice  cloth  hung  from  the  roof,  which  is  readily 
lifted  when  a  tram  waggon  has  to  pass  underneath.  In  the  case 
of  stopes  the  mode  of  procedure  is  identical,  but  the  air  current 
has  not  to  make  such  sharp  turns. 

The  case  represented  in  Fig.  568  is  that  of  workings  at  one  level. 
In  vein  mining  the  ore  is  generally  being  excavated,  or  at  all 
events  preliminary  drivages  are  being  made,  at  more  than  one 
horizon.  In  Fig.  571  two  shafts  have  been  sunk,  and  two 
drivages  have  been  made,  one  below  the  other.  It  is  easy  to 
understand  that  at  an  earlier  stage  of  the  working,  before  the 
shafts  had  been  sunk  to  E  and  F,  and  the  level  EF  driven, 


VENTILATION. 


489 


B      C 


a   current   was  set   up   from   A   to   C   via   B   and   D,  or  from 

C  to  A,  according  to  the  season  of  the  year ;  but  when  the  level 

EF  has  been  driven,  what  is  to  bring  the  current  down  to  E,  for 

instance,  when  it  has  the  shorter  and  easier  road  direct  from  B  to 

D  ?    It  often  happens 

that    special    condi-  FIG.  571. 

tions   in   the    shafts 

themselves,  to  which 

allusion   has  already 

been  made,  would  in 

any     case     cause     a 

movement  in  the  air 

from  B  to  E,  F  and 

D,    even  if  the   two 

columns  of  different 

height  did  not  exist 

above  them,   and  in 

that   case    some    air 

would   find   its   way 

down  to  E  and  F;    but   by   putting  a  door   at  G,    somewhere 

between  B  and  D,  the  main  current  can  be  forced  to  proceed  by 

the   longer   road  and  ventilate   the  lower  workings.      If    air  is 

required  for  men  working   in   the   level  BD,   the   partition,  or 

door  G,  is  not  made  close ;  then  part  of  the  main  current  takes 

the  shorter  road  from  B  to  D,  and  part  the  longer  road  from 

B  to  E,  F  and  D. 

Owing  to  the  number  of  shafts  which  are  usually  sunk  in 
working  veins,  and  differences  in  the  level  of  their  mouths,  natural 
currents  are  set  up  to  a  much  greater  extent  than  is  the  case  in 

working  beds,  where   a 

FIG.  572.  couple   of  pits  situated 

close  to  one  another  and 
at  the  same  level  have  to 
serve  as  the  sole  inlet 
and  outlet  orifices.  For 
this  reason  natural  ven- 
tilation is  often  found 
to  provide  a  fairly  suffi- 
cient supply  of  air  along 
the  main  course  of  the 
current,  and  the  miner 
has  merely  to  provide  for  the  ventilation  of  workings  in  the  form 
of  a  cul-de-sac,  such  as  ends,  rises,  and  winzes,  which  are  at  a 
distance  from  this  current. 

A  common  method  of  procedure  is  to  sink  winzes  at  frequent 
intervals  ;  if  AB  and  CD  (Fig.  572)  represent  two  levels,  10  to  15 
fathoms  apart,  which  are  being  driven  from  A  to  B  and  C  to  D 
respectively,  we  will  suppose  that  a  ventilating  current  exists  as 


J21 


490  ORE  AND  STONE-MINING. 

shown  by  the  arrows.  B  and  D  are  blind  alleys,  so  to  say,  but 
so  long  as  their  ends  B  and  D  are  not  far  from  the  main  draught, 
they  may  be  sufficiently  ventilated  by  convection  currents,  set 
up  in  the  manner  explained  in  Fig.  561.  Soon,  however,  this 
mode  of  supplying  air  becomes  inadequate,  and  the  miner  estab- 
lishes another  communication  between  the  two  levels  by  a  fresh 
winze  or  rise  JK;  the  current  is  made  to  take  the  road  shown 
by  the  dotted  arrow,  if  a  stopping  of  some  kind  is  put  into  the 
winze  FE.  The  name  "  winze,"  sometimes  written  "  winds," 
suggests  that  the  original  purpose  of  the  intermediate  shaft  was  to 
furnish  air.  In  some  mines  winzes  are  sunk  at  fairly  regular 
intervals  of  30  fathoms ;  of  course,  in  selecting  a  place  for  a 
winze,  preference  is  given  to  ore-bearing  parts  of  the  vein,  because 
the  cost  of  sinking  will  then  be  partly  or  wholly  repaid  by  the 
mineral  excavated.  Even  when  the  indications  at  the  top  may  not 
warrant  the  assumption  that  ore  is  present  in  paying  quantities, 
the  winze  serves  to  prove  the  ground  and  sometimes  to  reveal 
unsuspected  sources  of  profit.  Winzes  may  be  said,  then,  to  have 
five  useful  purposes  :  ventilation,  exploration,  starting-points  for 
stoping,  shoots  for  ore  or  rubbish,  ladder-roads  for  the  miners. 

I  have  thought  it  advisable  to  devote  more  space  to  natural 
ventilation  than  the  coal-miner  would  think  it  deserves,  because 
it  is  the  method  by  which  the  trunk  ventilation  of  most  vein- 
mines  is  carried  on  at  the  present  day,  and  has  been  carried  on 
for  centuries.  Nevertheless,  I  am  fully  alive  to  its  two  weak 
points — viz.,  want  of  constancy  and  want  of  strength.  The  miner- 
is  therefore  often  driven  to  seek  artificial  aid  in  order  to  make 
up  for  these  defects. 

ARTIFICIAL  VENTILATION.— Artificial  ventilation  is 
produced  either  by  (I.)  furnaces,  or  (II.)  machines. 

I.  FURNACE  VENTILATION. — By  employing  a  furnace, 
the  miner  can  effect  an  artificial  difference  of  temperature  between 
two  columns  of  air  in  the  mine,  and  so  produce  a  current  similar 
to  the  natural  draughts  just  described. 

In  small  undertakings  a  fire  lit  at  or  near  the  bottom  of  the 
upcast  shaft,  or  contained  in  an  iron  vessel  suspended  in  the  pit, 
suffices  to  create  a  current,  when  the  natural  ventilation  is  no 
longer  adequate,  owing  to  the  state  of  the  external  atmosphere. 
From  small  beginnings  of  this  kind  has  developed  the  large 
underground  furnace,  which  is,  however,  in  the  vast  majority  of 
cases,  confined  to  the  domain  of  the  coal-miner,  and  even  there  is 
being  gradually  replaced  by  fans.  My  description  may,  therefore, 
be  extremely  brief.  The  ventilating  furnace  (Figs.  573,  574, 
575)  *  is  a  huge  fireplace  at  or  near  the  bottom  of  the  upcast  shaft, 
over  which  is  led  either  all  the  air  of  the  mine,  or  a  part  of  it. 
The  air  heated  in  this  way  is  rendered  specifically  lighter,  and  the 

*  Callon,  Lectures  on  Mining,  vol.  ii.,  plate  Ixxxvi. 


VENTILATION. 


491 


weight  of  the  column  of  cold  air  in  the  downcast  shaft  overcomes 
that  of  the  air  in  the  upcast  and  causes  it  to  ascend.  It  is  pre- 
cisely the  same  action  as  that  which  takes  place  with  the  usual 
domestic  fireplace  in  this  country,  the  chimney  playing  the  same 
part  as  the  upcast  shaft.  Cold  air  is  drawn  in  from  crevices 
around  the  doors  and  windows,  is  heated  by  the  fire,  and  ascends 
the  chimney. 

If  the  air  of  the  workings  is  charged  with  a  dangerous  proportion 
of  inflammable  gas,  it  is  led  into  the  upcast  shaft  by  a  special 
drift — the  dumb  drift — at  u  point  where  there  is  no  danger  of  its 

FIG.  573- 


FIG.  574. 


taking  fire.  In  this  case  the  air  in  the  shaft  becomes  warmed  in 
its  upward  passage,  not  only  from  mixing  with  the  current  coming 
from  the  furnace,  but  also  by  absorbing  caloric  from  the  heated 
sides  of  the  pit. 

II.  MECHANICAL    VENTILATION.— The   methods   of 
mechanical  ventilation  may  be  classified  as  follows  : 

(1)  Water  blast. 

(2)  Steam  jet. 

{(i)  Reciprocating, 
fa.  Acting  by  displacement, 
(ii)  Rotary.  \ 

[6.       „        ,,  centrifugal  force. 

(i)  The  ordinary  water  blast  is  a  very  simple  appliance  :  it  is 
the  well-known  tromp,  used  in  some  countries  for  blowing  smiths' 


492  ORE  AND  STONE-MINING. 

forges.  A  stream  of  water  falls  down  a  pipe,  entangling  air 
drawn  in  by  lateral  holes,  and  drops  into  a  box  or  barrel  with  two 
orifices ;  these  are  so  arranged  that  the  air  shall  escape  by  one, 
under  a  slight  pressure,  and  the  water  from  the  other.  The  current 
of  air  is  carried  by  square  pipes  made  of  boards,  or,  better,  by 
cylindrical  pipes  made  of  sheet  zinc,  to  the  place  where  ventilation 
is  required. 

The  fall  of  water  is  also  applied  by  Williams's  water-jet 
apparatus  (Fig.  576).  The  water  brought  down  in  a  pipe 

from  a   reservoir,   or  from   the 

FIG.  576.  rising  main   of   the  column  of 

pumps,  issues  in  the  form  of  a 
jet  from  a  nozzle,  and,  driving 
out  the  air  in  front  of  it,  draws 
in  air  behind.  The  water  is  let 
off  by  a  box  with  a  discharge 
designed,  like  that  of  the  tromp, 
to  give  a  little  pressure,  whilst 

the  air-current  proceeds  through  a  series  of  pipes  to  the  "  end  " 
or  other  working-place.  The  water-blast  has  the  merit  of  supply- 
ing a  stream  of  cool  moist  air  which  is  very  acceptable  where 
the  working-place  is  dry  and  dusty.  By  reversing  the  apparatus 
the  current  may  be  made  to  flow  in  the  opposite  direction,  and 
the  "  end "  is  then  ventilated  by  having  its  foul  air  drawn  out 
and  replaced  by  an  inward  draught  along  the  level,  instead  of 
being  supplied  directly  with  fresh  air  from  the  outside  or  from 
the  main  ventilating  current. 

(2)  A  steam  jet  may  be  applied,  like  a  jet  of  water,  to  create 
an  exhaust  and  to  draw  out  the  foul  air.     For  instance,  we  will 
suppose  that  during  the  sinking  of  a  shaft  the  air-pipe  in  Fig.  569 
fails  to  act  in  an  adequate  manner,   owing  to  a  change  in  the 
atmospheric  conditions.     The  agent  desires  to  remedy  this  state 
of  affairs  by  some  cheap  and  temporary  expedient.     If  he  brings 
a   pipe   from  the  boiler  of  the  winding  engine  to  the  upright 
ventilating  pipe,  and  provides  it  with  a  nozzle  pointing  upwards, 
he    can   speedily    and    at    small    expense    produce    an   upward 
current  by  turning  on  steam.     The  steam  jet  drives  air  in  front 
of  it  up  the  pipe,  and  at  the  same  time  warms  it  slightly.     The 
exhausting  effect  produced  in  this  way  at  the  bottom  of  the  pipe 
is  sufficient,  in  small  sinkings,  to  draw  out  all  the  foul  air. 

A  draught  may  be  produced  in  an  upcast  shaft  by  a  ring  at 
the  bottom,  from  which  issue  a  number  of  jets  of  steam.  Such  a 
mode  of  ventilation  may  be  useful  in  cases  of  emergency. 

(3)  Air  Pumps. — Mechanical  ventilation  on  a  large  scale  is 
always  effected  by  some  kind  of  air  pump,  and  generally  by  one 
which  has  a  rotary  action. 

(i)  Among  the  pumps  which  have  a  reciprocating  action,  the 
ordinary  air  compressor  must  be  named  first,  as  its  utility 


VENTILATION.  493 

as  a  ventilating  agent  is  great.  The  air  escaping  from  boring 
or  other  machines  renders  good  service  in  driving  out  foul 
gases  generated  in  the  workings,  and  there  is  the  advantage  that, 
after  blasting,  a  powerful  stream  of  air  can  be  turned  on  for  a 
short  time  so  as  to  sweep  out  the  noxious  fumes  completely. 
Even  where  the  ground  is  soft  and  no  machine  drill  required,  it 
is  easy  to  bring  in  air  from  the  main  by  a  line  of  smaller  pipes, 
and  turn  on  a  fresh  current  when  needed.  In  one  sense  it  is 
very  uneconomical  to  bring  air  to  a  pressure  of  60  or  yolbs. 
to  the  square  inch  for  ventilating  purposes  only;  but  where 
compressing  machinery  is  always  at  hand  for  working  underground 
engines,  it  is  better  to  be  a  little  wasteful  of  a  cheap  power 
at  the  surface  than  to  go  to  the  greater  expense  of  having  a  boy 
or  a  man  to  work  a  fan. 

In  a  long  level  driven  by  boring  machinery,  with  its  "  end  " 
far  removed  from  the  main  ventilating  current,  the  smoke 
produced  by  blasting,  though  driven  away  from  the  actual 
working  face,  still  hangs  about  for  a  time,  and  pollutes  the 
atmosphere  which  the  miner  has  to  breathe  in  going  backwards 
and  forwards.  In  such  cases  it  is  best  to  draw  away  the  foul 
gases  as  soon  as  they  have  been  produced,  and  prevent  their 
mixing  with  the  air  of  the  level.  With  compressed  air  at 
his  command,  the  miner  can 

easily    work    an    aspirator    of  FIG.  577. 

some  kind,  such  as  Korting's, 
or  the  somewhat  similar  con- 
trivance of  Mr.  Teague  (Fig. 
577).  The  ordinary  air-main 
for  bringing  in  the  compressed 

air   working    the    boring    mn-  _-_; 

chinery  is  shown  at  the  bottom 

of  the  level,  with  the  piece  of  flexible  hose  at  the  end.  The 
boring  machine  has  been  removed  and  the  air  shut  off  from  the 
hose;  by  turning  another  cock,  it  passes  up  the  upright  piece 
of  pipe  and  rushes  out  of  the  nozzle  in  a  direction  opposed 
to  that  of  the  drivage.  This  has  a  powerful  exhausting  effect,, 
and  the  "  end  "  can  be  cleared  of  smoke  in  a  few  minutes. 

The  Hartz  blower  (duck  machine,  Cornwall)  (Figs.  578  and  579) 
is  an  air  pump  of  simple  construction  which  can  be  made  up  by 
any  mine  carpenter.  It  consists  of  two  round  or  rectangular 
boxes,  one  fitting  inside  the  other,  and  moved  up  and  down  by 
being  connected  to  the  main  rod  of  the  pumps ;  the  upper  box 
has  a  valve  at  the  top,  and  the  lower  box  is  provided  with  a  pipe 
also  having  its  valve.  The  lower  box  is  partly  filled  with  water 
so  as  to  make  an  airtight  connection.  With  the  valves  arranged 
as  shown  in  Fig.  579,  the  machine  will  act  as  an  exhausting 
pump  and  draw  out  the  foul  air ;  if  the  play  of  the  valves  is 
reversed  it  acts  as  a  blower. 


494 


ORE  AND  STONE-MINING. 


Struve's  ventilator  is  a  gigantic  double-acting  machine  of  this 
class,  so  constructed  that  it  draws  air  from  the  mine  during  the 
down  stroke  as  well  as  during  the  up  stroke. 

(ii)  a.  Among  the  rotary  air  pumps  acting  by  displacement  may 
be  mentioned  Boots's  ventilator,  of  which  various  sizes  are  made, 
suitable  to  the  requirements  of  the  whole  of  a  large  mine  or 
merely  to  those  of  a  single  "  end." 

This  air  machine  (Fig.  580)  consists  essentially  of  two  similar 
pistons  upon  parallel  shafts,  revolving  in  a  casing,  but  without 
actually  touching  each  other  or  the  casing.  The  clearance  in  a 
large  ventilator  is  under  \  inch.  The  pistons  are  of  such  a  shape 


FIG.  578.      FIG.  579. 


FIG.  580. 


that  a  definite  volume  of  air  is  drawn  in  or  forced  out  by  each 
half-revolution.  As  the  pistons  are  always  kept  in  position  by 
gearing,  there  is  no  fear  of  one  coming  in  contact  with  the 
other. 

(ii)  b.  Centrifugal  Ventilators  or  Fans. — This  class  includes 
all  the  most  important  ventilators  in  use  at  the  present  day. 
They  are  characterised  by  the  fact  that  the  current  is  produced 
by  blades  or  vanes  fixed  to  a  shaft,  revolving  at  a  high  speed. 
The  air  lying  between  them  is  whirled  round  and  flies  off  tangen- 
tially  at  the  tips,  like  a  stone  from  a  sling.  The  space  occupied  by 
this  air  is  at  once  filled  by  supplies  coming  in  at  the  centre,  and 
the  process  goes  on  continuously.  The  centrifugal  ventilators  or 
fans  are  generally  used  as  exhausters — that  is  to  say,  they  are 
arranged  so  as  to  suck  air  out  of  the  mine,  instead  of  forcing  it  in. 
They  can  claim  the  merit  of  great  simplicity,  and  of  being  capable 
of  withdrawing  very  large  volumes  of  air. 


VENTILATION. 


495 


Four  types  of  fans  very  largely  used  in  this  country  at  the  present 
day  are  the  following :  Oapell,  Guibal,  Schiele  and  Waddle. 

The  Capell  fan  (Figs.  581  and  582)  consists  of  two  concentric 
cylindrical  chambers,  each  provided  with  six  curved  vanes  or 
blades,  the  convex  sides  of  which  are  turned  in  the  direction  of 
the  rotation.  The  cylindrical  shell  or  drum,  6,  between  the  two 
sets  of  vanes  contains  openings,  or  portholes,  d  d,  allowing  the  air 
to  pass  from  the  inner  to  the  outer  chambers.  There  is  one 
such  opening  between  every  two  vanes.  The  air  contained 
between  any  two  of  the  inner  vanes,  c,  is  thrown  out  by  centri- 
fugal force  when  the  fan  revolves,  and  passes  at  a  high  velocity 
into  the  corresponding  outer  chamber.  Here  it  is  supposed  to 
strike  against  the  concave  vane,  and  give  back  to  it  the  greater 
part  of  the  impulse  received  from  the  inner  chamber.  The 
object  of  the  inventor  of  this  and  of  other  fans  is  to  discharge 


FIG.  581. 


FIG.  582. 


the  air  with  the  least  possible  velocity,  for  velocity  imparted  to  the 
outgoing  air  means  work  done  to  no  purpose,  or,  in  other  words,  a 
diminution  of  the  useful  effect  of  the  power  employed  in  driving. 
The  advantage  claimed  for  the  fan  is  that  it  succeeds  in  effect- 
ing this  object  even  when  driven  at  a  high  speed,  and  that, 
therefore,  it  can  do  a  large  amount  of  work  in  spite  of  its  com- 
paratively small  diameter.  The  smallness  of  the  fan  of  course 
reduces  its  first  cost.  It  is  not  only  capable  of  withdrawing  large 
quantities  of  air,  but  also  of  effecting  a  considerable  diminution 
of  pressure. 

The  fan  may  be  made  with  an  inlet  on  one  side  only  or  with  an 
inlet  on  both  sides.  It  runs  in  a  spiral  casing,  not  fitting  closely, 
which  gradually  gives  a  larger  and  larger  outlet  for  the  air  and 
then  finally  discharges  it  into  an  expanding  chimney.  Figs.  581  and 
582  show  a  double  inlet  fan,  a  being  the  close  vertical  diaphragm 
separating  it  into  two  parts.  A  special  passage  (fan  drift)  brings 
the  air  from  the  upcast  shaft  to  the  ventilator,  which  is  set  in 
motion  by  a  belt  driven  by  the  fly-wheel  of  a  pair  of  horizontal 
•engines. 

These  fans  are  made  of  diameters  varying  from  8  to  15  feet; 


496 


ORE  AND  STONE-MINING. 


the  width  of  the  small  ones  is  7  feet,  that  of  the  largest  1 1 J  feet ; 
they  are  driven  at  speeds  varying  from  180  revolutions  per 
minute  in  the  case  of  the  largest  fans,  to  300  in  the  case  of  the 
smallest.  Under  these  conditions  the  smallest  fan  is  said  to  be 
capable  of  passing  a  volume  of  100,000  cubic  feet  of  air  per 
minute,  with  a  diminution  of  pressure  (water-gauge)  of  2\  inches, 
whilst  the  large  fan  moves  the  enormous  quantity  of  300,000  cubic 
feet  per  minute.  The  power  required  is  estimated  at  60  I.H.P.  in 
one  case  and  180  in  the  other. 

The  Guibal  fan,  brought  to  us  from  Belgium  (Fig.  583),  has 
deservedly  been  a  favourite  for  many  years.  It  is  a  fan  with  eight 

or    ten    straight 

FIG.  583.  blades,    which    are 

not  set  radially.  An 
important  peculia- 
rity, introduced  by 
Guibal  and  since 
copied  by  others,  is 
the  expanding  stack 
or  chimney,  which 
gradually  lessens 
the  velocity  of  the 
air  as  it  travels 
towards  the  point 
of  discharge  into 
the  outer  atmo- 
sphere, and  the  slid- 
ing shutter,  a.  The 
shutter  enables  the 
opening  of  the  fan- 
casing  into  the  ex- 
panding chimney  to 
be  regulated  at  pleasure :  if  this  opening  is  too  big,  eddies  are 
formed  and  air  re-enters  the  fan ;  if,  on  the  other  hand,  the  opening 
is  too  restricted,  an  unnecessary  amount  of  force  is  required  to- 
work  the  fan,  and  the  air  escapes  with  too  great  velocity.  By 
careful  regulation  the  best  possible  effect  is  attained. 

The  regulating  shutter  has  been  greatly  improved  by  Messrs. 
"Walker  Brothers  of  Wigan,  who  make  the  opening  in  the  form  of 
an  inverted  V,  with  the  object  of  producing  a  gradual  instead  of  a 
sudden  change  as  each  blade  passes  into  the  enclosed  part  of 
the  casing.  The  consequence  is  that  the  amount  of  vibration  is. 
greatly  reduced  and  the  fan  rendered  nearly  noiseless.  They 
build  their  fans  entirely  of  iron  or  steel. 

Guibal  fans  are  made  of  diameters  varying  from  20  to  46  feet,. 
and  widths  varying  from  6  to  13  feet.  Fans  30  feet  in  diameter 
are  usually  driven  at  a  speed  of  about  sixty  revolutions  per 
minute,  and  the  large  fans  of  40  to  46  feet  at  fifty  revolutions. 


VENTILATION. 


497 


The  Schiele  fan  is  somewhat  like  the  Guibal.  It  has  the  same 
expanding  chimney,  but  the  blades  are  curved  and  the  casing  is 
not  close  (Fig.  5  84) ;  besides, 

the  width  of  the  blades  is  FIG.  584. 

not  the  same  throughout. 
The  blade  is  widest  in  the 
middle,  and  then  it  de- 
creases both  towards  the 
centre  of  the  fan  and  to- 
wards the  tips.  It  is  a 
small  fan  compared  with 
the  Guibal,  the  diameter 
varying  from  5  to  20  feet, 
width  from  i  to  3  feet. 
The  speed  of  driving  is  500 
revolutions  per  minute  for 

the  smallest  fans  and  no  per  minute  for  the  largest.     The  air 
is  always  taken  in  on  both  sides. 

We  come  lastly  to  the  Waddle  fan,  which  differs  from  those  just 
described  by  running  open — that  is  to  say,  it  is  not  enclosed  in  any 
external  casing  (Fig.  585).  It  is  a  very  flat  hollow  truncated 
cone,  with  the  base  closed  and  a  central  opening  on  the  other 

FIG.  585. 


side.  Originally  the  blades  a  b  were  curved,  as  shown  in  the  figure, 
but  latterly  they  have  been  made  radial ;  c  c  are  some  of  the 
outer  plates.  The  air  passes  in  at  the  centre  and  is  discharged 
at  the  circumference.  These  fans  are  made  with  a  diameter 
of  30  to  45  feet.  A  recent  improvement  is  the  addition  of  a 

2  I 


4g8  ORE  AND  STONE-MINING. 

divergent  outlet — in  other  words,  the  two  rims  projecting  beyond 
the  blades  are  inclined  outwards.  The  velocity  of  the  air  leaving 
the  fan  is  thus  lowered,  and  less  power  is  required  for  driving. 
A  Waddle  fan,  described  by  Mr.  Walton  Brown,*  had  the  following 
dimensions : 

Ft.    in. 

Diameter  to  periphery  of  divergent  outlet  36    4 

,,        of  the  extremities  of  the  blades  35     o 

,,  ,,      inlet  ring  ...  136 

Width  at  outlet i     i£ 

,,       ,,  periphery  of  fan          ...  2     2j 

The  Waddle,  like  the  Guibal,  is  a  slow-running  fan,  which  can 
be  driven  directly  from  the  engine  without  the  aid  of  belts  or 
gearing. 

Professor  Luptonf  has  designed  a  fan,  which  he  calls  the 
Medium  fan,  in  which  he  considers  that  he  has  brought 
together  the  good  points  both  of  the  large  fans,  such  as  th& 
Guibal  and  the  Waddle,  and  of  the  small  fans,  such  as  the 
Schiele  and  the  Capell.  It  is  from  15  to  25  feet  in  diameter. 

TESTING  THE  QUALITY  OF  THE  AIR.— In  a  well- 
regulated  mine  the  manager  should  be  able  to  determine  the 
quality  and  quantity  of  the  air  circulating  in  the  workings,  and 
the  efficiency,  from  a  mechanical  point  of  view,  of  the  machinery 
employed  for  ventilation. 

A  knowledge  of  the  quality  of  the  air  is  necessary  for  two 
reasons  :  it  may  contain  gases  capable  of  causing  accidents  by 
explosion  or  suffocation,  or  it  may  be  polluted  by  gaseous  and 
other  impurities  likely  to  injure  the  health  of  the  men  who  have 
to  breathe  it. 

Fire-damp. — Though  ore  and  stone  miners  are  rarely  exposed 
to  any  danger  from  fire-damp,  exceptional  cases  arise  in'  which  car- 
buretted  hydrogen  is  emitted  naturally  or  formed  artificially  in 
mines,  as  mentioned  in  the  beginning  of  this  chapter.  It  is  therefore- 
essential  that  the  miner  should  have  some  knowledge  of  the 
means  employed  in  testing  for  fire-damp,  even  if  he  is  not  going 
to  manage  a  colliery.  However,  the  subject  must  be  treated 
briefly,  and  the  student  desirous  of  further  information  may 
be  referred  to  treatises  on  coal -mining. 

Indications  of  fire-damp  are  afforded  by  the  singing  noise  made 
by  the  gas  if  it  is  issuing  forth  in  large  quantities  from  moist  coal,, 
by  its  bubbling  up  in  water,  and  by  the  cracking  noise  of  bubbles 
as  they  burst ;  but  its  presence  is  commonly  detected  by  its  effect 
upon  the  flame  of  a  lamp  burning  oil,  benzine,  alcohol,  or  hydrogen. 
The  additional  brilliancy  which  it  imparts  to  a  platinum  wire  made 
incandescent  by  the  passage  of  an  electric  current  may  also  be 
employed  as  a  test,  or  the  diminution  in  the  volume  of  a  measured 

*  "  Waddle  Patent  (1890)  Fan,"  Trans.  Fed.  Inst.  M.  E.,  vol.  ii.,  1890- 
91,  p.  173. 
t  Notes  on  the  Medium  Fan,  Proc.  Fed.  Inst.  M.  E.,  vol.  i.,  1890,  p.  65. 


VENTILATION.  499 

quantity  of  air,  exposed  to  the  action  of  a  red-hot  palladium  or 
platinum  wire,  causing  combustion. 

The  lamp  employed  should  be  a  safety  lamp,  for  fear  that  an 
accidental  ignition  of  the  gas  should  cause  an  explosion.  A  few 
safety  lamps  will  be  described  in  the  next  chapter.  They  are  fed 
with  vegetable  or  mineral  oil,  or  with  a  mixture  of  them.  In  test- 
ing for  "gas,"  the  wick  is  drawn  down  until  the  yellow  flame  almost 
disappears,  and  the  lamp  is  held  in  the  place  where  the  fire-damp 
is  supposed  to  be  present ;  on  account  of  its  specific  lightness 
it  lodges  against  the  roof,  and  it  is  there,  if  anywhere,  that  it 
is  most  likely  to  be  found.  If  fire-damp  is  present  in  sum- 
cient  quantity,  its  combustion  produces  a  pale  blue  "cap"  (halo, 
or  aureola)  around  the  little  flame,  and  the  greater  the  proportion 
of  fire-damp,  the  higher  the  cap.  According  to  Professor 
Galloway  *  2  per  cent,  of  fire-damp  in  the  air  will  give  an  exceed- 
ingly faint  cap  J  inch  high,  whilst  4  per  cent,  gives  a  conical  cap 
J  to  |  inch  high.  If  a  lamp  fed  with  benzine  is  used,  the  phe- 
nomena are  plainer.  The  appearances  of  the  flame  burning 
in  mixtures  of  air  and  marsh-gas  of  different  proportions  are 
well  represented  by  coloured  plates  in  a  report  made  by  Professors 
Kreischer  and  Winkler,f  and  in  the  Proceedings  of  the  Austrian 
Fire-damp  Commission.  {  With  i  per  cent,  of  fire-damp  there 
is  a  faint  aureola,  and  with  2  per  cent,  it  is  plain,  conical  at  the 
top  and  §  inch  (10  mm.)  high  ;  when  the  proportion  is  increased 
to  3  per  cent.,  there  is  a  well-defined  cap  f  inch  (20  mm.)  high. 
By  using  a  dead-black  background,  it  is  claimed  that  Ashworth's 
modified  benzoline  safety -lamp  §  will  give  a  distinct  cap  J  inch  high 
with  J  per  cent,  of  fire-damp. 

The  blue  non-luminous  flame  of  alcohol  enables  still  smaller 
quantities  of  fire-damp  to  be  made  known,  and  the  Pieler  lamp  || 

*  "On  the  Fire-damp  Cap,"  Proc.  South  Wales Inst.  JEng.,  vol.  x.,  1876-7, 
p.  290. 

"  Untersuchungen  itber  Sicherheitslampen,"  Jahrb.  f.   d.    Berg-  und 
Huttenwesen  im  K.  Saclisen,  1884,  p.  54,  and  plates  ii.  to  vi. 

J  Verhandlungen  der  Centralcomit6s  der  osterreichischen  Commission  zun 
Ermittlung  der  zweckmdssigsten  Sicherheitsmaassregeln  gegen  die  Explosion, 
scUagender  Wetter  in  Hergwerken.  3  Heft.  Vienna,  1890,  plates  ii.  and  iii., 
p.  225. 

§  Clowes,  "  On  the  Application  of  the  Hydrogen  Flame  in  an  ordinary 
Safety-lamp  to  the  Detection  and  Measurement  of  Fire-damp,"  Proc. 
Boy.  Soc.,  vol.  Ii.  1892,  p.  90. 

||  Pieler,  Veber  einfache  Methoden  zur  Untersuchung  der  Grubenwetter, 
Aix-la-Chapelle,  1883.  Kreischer  and  Winkler,  op.  cit.,  p.  77.  C.  Le 
Neve  Foster,  "  On  the  Pieler  Lamp  for  indicating  small  quantities  of  Fire- 
damp," Trans.  Geol.  Soc.  Manchester,  vol.  xvii.,  1884,  p.  252.  Broockmann, 
"  Untersuchung  der  durch  Sumpfgas  hervorgebrachten  Erscheinungen 
der  Pieler- Lampe,"  Anlagen  zum  Haupt-Bericlde  der  Preussischen  /Schlag- 
wetter  Commission,  vol.  i.,p.  129,  vol.  iii., p.  167,  and  plates.  Walton  Brown, 
"  The  Pieler  Spirit-lamp  as  a  Fire-damp  Indicator,"  Trans.  N.  E.  Inst. 
M.  E.,  vol.  xxxviii.,  1890,  p.  177  and  plates.  Austrian  Fire-damp  Com- 
mission, op.  cit.,  plate  iv. 


500  ORE  AND  STONE-MINING. 

is  based  upon  this  fact.  It  begins  to  indicate  with  J  per  cent, 
of  fire-damp,  and  even  with  ^  per  cent,  the  cap  or  aureola  is 
2  to  2  J  inches  high,  and  clearly  recognisable ;  with  i  per  cent. 
it  is  nearly  4  inches  high. 

Chesneau  *  obtains  a  plainer  and  more  brilliant  cap  by  adding 
a  little  nitrate  of  copper  and  an  organic  chloride  to  the  alcohol, 
and  Stokes  has  introduced  the  improvement  of  combining  a 
detachable  alcohol-reservoir  with  an  ordinary  safety-lamp,  and 
so  enabling  the  official  to  test  with  the  oil  or  the  spirit  flame  at 
pleasure. 

Mallard  and  Le  Chatelier  pointed  out  the  value  of  the  hydrogen 
flame  as  a  fire-damp  indicator  in  a  report  to  the  French  Fire-damp 
Commission,  and  Pieler  made  use  of  it  for  testing  samples  of  mine 
air  which  were  brought  to  a  laboratory  at  the  surface.  Quite 
recently  Prof.  Clo  west  has  constructed  a  hydrogen  lamp  sufficiently 
portable  for  use  underground  in  the  working  places  themselves. 
The  lamp  is  so  constructed  that  it  will  burn  either  an  illuminat- 
ing oil  or  hydrogen  as  required.  A  little  tube  is  brought  up  through 
the  oil  reservoir,  and,  on  turning  a  cock,  a  jet  of  hydrogen  issues 
forth  close  to  the  ordinary  oil  flame.  It  ignites  at  once,  and 
the  wick  of  the  oil  flame  is  pulled  down  till  it  goes  out ;  the 
non-luminous  hydrogen  flame  now  serves  as  a  delicate  indicator. 
The  oil  flame  is  relighted  from  the  hydrogen  flame  when  the 
testing  is  concluded,  and  the  gas  is  then  turned  off.  The  cap 
with  J  per  cent,  of  fire-damp  is  f  inch  (17  mm.)  high,  and  with 
i  per  cent,  it  is  |  inch  (22  mm.)  high.  The  hydrogen  is  contained 
in  a  small  steel  cylinder  which  can  be  attached  to  the  lamp  in  the 
form  of  a  handle. 

The  combination  of  a  very  delicate  testing  apparatus  with  the 
ordinary  lamp  has  the  advantage  of  enabling  the  official  to  do 
his  work  with  one  lamp  instead  of  two. 

Liveing'sJ  patent  gas  indicator  depends  upon  the  fact  that 
fine  platinum  wire,  made  red-hot  by  the  passage  of  an  electric 
current,  will  glow  with  greater  brilliancy  when  there  is  fire- 
damp present  in  the  atmosphere  than  when  there  is  none. 
This  phenomenon  is  due  to  the  heat  given  off  by  the  com- 
bustion of  the  fire-damp  in  immediate  contact  with  the  wire; 
and  the  greater  the  heat,  the  more  the  wire  will  glow.  The 
increase  in  brilliancy  corresponding  to  a  given  percentage  of  fire- 

*  "  Notes  sur  un  nouvel  indicateur  de  grisou  ;  "  "  Essais  effectues  dans  les 
mines  avec  1'indicateur  de  grisou  de  G.  Chesneau  ;  "  "  Instruction  pour 
1'emploi  de  1'indicateur  de  grisou  de  G.  Chesneau,"  Ann.  des  Mines,  Paris, 
1892  and  1893.  Comptes-rendus  Soc.  Ind.  Min.,  1894,  p.  25. 

t "  On  the  Application  of  the  Hydrogen  Flame  in  an  ordinary  Safety- 
lamp  to  the  Detection  and  Measurement  of  Fire-damp,"  Proc.  Boy.  Soc., 
vol.  li.,  1892,  p.  90. 

£  Liveing,  On  an  Instrument  for  the  Detection  and  Measurement  of  Inflam- 
mable Gas  in  the  Atmosphere  of  Mines.  L.  Clark,  Muirhead  and  Co.,  West- 
minster, London,  1881. 


VENTILATION.  501 

damp   is   measured   by   a  small    photometer,   which   cannot   be 
understood  without  a  figure. 

Shaw's  apparatus  is  based  upon  the  principle  of  determining  the 
limits  of  inflammability  of  gaseous  mixtures,  or,  in  other  words, 
of  ascertaining  the  precise  degree  of  dilation  which  renders  the 
mixture  just  capable  of  being  ignited.  It  consists  of  two  main 
parts,  an  ingenious  mixing  apparatus  and  an  exploding  chamber. 
By  the  aid  of  the  first,  a  mixture  of  pure  air  with  inflammable 
gas,  or  with  mine  air,  can  be  prepared  in  any  desired  proportions, 
and  then  driven  into  a  cylinder,  where  it  meets  with  a  naked  flame, 
If  the  mixture  contains  a  sufficient  proportion  of  inflammable  gas 
to  explode,  a  loose  stopper  is  blown  out  and  strikes  a  bell,  giving 
an  audible  signal.  By  making  a  succession  of  experiments,  the 
exact  volume  of  mine  air  required  to  bring  a  known  mixture  of 
gas  and  air  to  the  ignition  point  can  be  ascertained,  and  from  this 
the  percentage  of  fire-damp  is  determined.  Samples  of  mine  air 
can  thus  be  tested  at  the  surface  with  a  considerable  amount  of 
accuracy  by  any  intelligent  foreman. 

Carbonic  Acid. — Two  evils  are  feared  from  the  presence  of  this 
gas  in  the  atmosphere  of  mines — either  suffocation  when  the  pro- 
portion is  large,  or  injury  to  health  when  the  proportion  is  smaller. 
If  the  gas  is  issuing  from  the  rocks,  it  settles  down  at  the  bottom 
of  the  excavation  in  virtue  of  its  specific  gravity,  and  men  have 
been  asphyxiated  by  descending  into  shafts  or  wells  in  which  the 
gas  had  accumulated  without  their  knowledge.  Where  danger  of 
this  kind  may  be  apprehended — for  instance,  in  mines  known  to 
be  liable  to  emissions  of  carbonic  acid,  or  in  the  case  of  old  work- 
ings that  have  not  been  recently  entered,  the  usual  test  is 
lowering  a  lighted  candle.  If  the  candle  is  found  to  burn 
brightly,  it  is  concluded  that  there  will  be  no  danger  in  making 
the  descent ;  if  it  goes  out,  it  is  evident  that  the  air  is  unfit  to 
support  combustion  and  human  life ;  if  it  burns  dimly,  there  is 
need  for  the  greatest  caution. 

The  ore  and  stone  miner  also  relies  upon  the  candle  for  testing 
the  air  of  his  working  place,  in  cases  where  the  proportion  of 
carbonic  acid  falls  very  far  short  of  that  required  to  produce  suffo- 
cation. He  is  apt  to  consider  that  if  the  candle  burns  freely  when 
held  upright,  and  does  not  go  out  when  moved  quickly  from  side 
to  side,  the  ventilation  must  be  good.  Dr.  Angus  Smith  states  in 
his  report  to  Lord  Kinnaird's  Commission  *  that  this  is  a  fallacy, 
and  he  considers  that  the  candle  test  affords  no  distinct  sign  that 
the  air  is  bad,  until  the  impurities  have  reached  an  amount  beyond 
the  maximum  which  is  consistent  with  good  ventilation.  Thus, 
the  candle  affords  no  indication  of  the  presence  of  J  per  cent,  of 
carbonic  acid  ;  if  the  percentage  is  greater  than  this  he  says  that 
men  should  not  be  allowed  to  work,  and,  to  use  his  own  words, 
"it  follows  therefore  that  the  candle,  as  used,  is  only  valuable 
*  Op.  cit.  Appendix  B,  p.  254. 


502  ORE  AND  STONE-MINING. 

when  the  air  is  so  bad  that  no  one  should  be  allowed  to  remain 
in  it." 

He  is  of  opinion  that  the  carbonic  acid  of  dwelling  rooms 
should  not  be  allowed  to  exceed  0-06  or  o'oy  per  cent.,  and 
agrees  with  Pettenkofer,*  who  lays  down  o'i  per  cent,  of  the  gas 
as  the  beginning  of  decidedly  bad  ventilation.  The  latter  says : 
"  A  series  of  examinations  have  resulted  in  the  conviction  that 
one  volume  of  carbonic  acid  in  1000  volumes  of  room  air  indicates 
the  limits  which  divide  good  from  bad  air.  This  is  now  generally 
adopted  and  practically  proved,  always  provided  that  man  is  the 
only  source  of  carbonic  acid  in  the  space  in  question."  Other  good 
authorities  f  write  to  the  same  effect. 

Such  small  percentages  of  carbonic  acid,  which  are  wholly 
unrecognisable  by  the  candle  test,  can  be  readily  detected  and 
easily  measured  by  methods  which  are  quite  within  the  powers  of 
an  ordinary  mine  agent. 

Angus  Smith 's  Process. — The  first  process  is  one  proposed  by 
Dr.  Angus  Smith  J  in  1864 — viz->  shaking  a  known  quantity  of 
lime-water  with  a  known  volume  of  air,  and  observing  whether 
there  is  sufficient  carbonic  acid  in  the  air  to  neutralise  the  lime. 
The  only  alteration  I  propose  is  the  use  of  phenolphthalein  as  an 
indicator,  instead  of  turmeric  paper  or  rosolic  acid. 

The  necessary  apparatus  consists  simply  of : 

1.  One  8-oz.  bottle  and  cork. 

2.  One  5-oz.  bottle  and  cork. 

3.  One  bottle  of  lime-water  with  excess  of  lime. 

4.  One  pipette  or  measure  holding  \  oz. 

5.  Four  3-oz.  bottles  corked. 

6.  One  £-oz.  bottle  containing  an  alcoholic  solution  of  phenol- 

phthalein. 

7.  One  piece  of  india-rubber  tube,  about  a  foot  long. 

According  to  Dr.  Angus  Smith,  lime-water  is  fairly  constant 
in  strength,  and  sufficiently  so  for  his  process  of  air-testing. 
After  the  bottle  (No.  3)  has  been  well  shaken  up  several  times 
with  the  excess  of  lime,  the  solution  is  allowed  to  stand  till 
it  is  quite  clear.  \  ounce  of  it  is  measured  exactly,  and  poured 
into  the  5 -ounce  bottle,  which  is  then  filled  up  with  distilled  water 
or  boiled  rain-water.  This  gives  a  solution  of  one-tenth  the 
strength  of  the  original  lime-water.  Add  a  drop  or  two  of  the 
solution  of  phenolphthalein,  and  the  lime-water  at  once  assumes 

*  The  Relations  of  the  Air  to  the  Clothes  we  Wear,  the  House  we  Live  in,  and 
the  Soil  we  Dwell  on.  Abridged  and  translated  by  Augustus  Hess.  London, 

1873- 

f  Parkes  and  de  Chaumont,  "  A  Manual  of  Practical  Hygiene,'"  6th 
edition,  London,  1883,  p.  153.  Meymott  Tidy,  "  Handbook  of  Modern 
Chemistry,'1'  London,  1878,  p.  102. 

£  Op.  cit.  Appendix  B,  p.  239.  C.  Le  Neve  Foster,  "  On  One  of  Dr. 
Angus  Smith's  Methods  of  Testing  Air,"  Trans.  Min.  Assoc.  and  Inst. 
Corn.,  vol.  ii.,  part  2,  p.  40. 


VENTILATION.  503 

a  beautiful  pink  colour,  which  remains  so  long  as  there  is  any 
lime  un-neutralised.  This  dilute  lime-water  is  now  of  a 
strength  that  J  ounce  of  it  will  neutralise  the  carbonic  acid  in 
an  8-ounce  bottle,*  if  the  air  in  it  contains  -}  per  cent,  of  this  gas 
by  volume.  This  percentage  has  been  proposed  as  a  standard 
which  should  not  be  exceeded. 

In  order  to  make  a  test,  fill  the  8-ounce  bottle  with  the  air 
of  the  place,  by  sucking  out  its  contents  with  a  piece  of  india- 
rubber  tube,  of  course  taking  special  care  not  to  breathe  into 
it  afterwards ;  then  add  |-  ounce  of  dilute  lime-water,  cork  the 
bottle  and  shake  it.  If  the  pink  colour  disappears,  the  air 
contains  more  than  £  per  cent,  of  carbonic  acid  ;  if  the  colour 
is  not  discharged,  the  air  contains  less  than  that  amount.  If 
the  colour  fades  slowly,  and  does  not  finally  vanish  until  after  a 
great  deal  of  shaking,  it  may  be  assumed  that  the  percentage  of 
carbonic  acid  does  not  greatly  exceed  J,  whereas  if  the  disappear- 
ance is  rapid  after  a  few  shakes,  the  contrary  of  course  is  the  case. 

It  need  hardly  be  said  that  the  accuracy  of  the  process  depends 
upon  the  precision  with  which  the  solution  is  measured,  and  for 
this  purpose  a  pipette,  or  a  burette,  will  do  better  than  a 
graduated  glass  cup.  I  think  it  best  to  carry  each  separate  J- 
ounce  of  lime-water  in  its  own  bottle,  and  it  is  well  to  see  by  actual 
measurements  that  ^  ounce  can  be  poured  from  the  little  bottle, 
for  a  few  drops  always  remain  behind. 

However,  even  if  all  precautions  are  taken,  the  observations 
cannot  pretend  to  vie  with  Dr.  Hesse's  method  (p.  505)  in  accuracy, 
because  changes  of  temperature  and  pressure  alter  the  weight 
of  the  air  contained  in  the  8-ounce  bottle.  Luckily  in  the  case 
of  mines,  the  two  sources  of  error  act  in  opposite  directions, 
and  sometimes  may  neutralise  each  other,  the  tendency  to  expand, 
owing  to  increased  temperature,  being  counteracted  by  a  greater 
barometric  pressure  due  to  the  depth  of  the  mine. 

A  leather  case  containing  an  8-ounce  bottle  and  four  half- 
ounces  of  lime-water,  by  means  of  which  four  tests  can  be  made, 
measures  only  7^  inches  by  3^  inches  by  2§  inches,  and  is  sufficiently 
portable  to  be  easily  carried,  even  when  climbing  up  "rises"  or 
"stopes.". 

Lunge's  Apparatus. — Instead  of  simply  deciding  whether  or  no 
the  carbonic  acid  exceeds  the  proposed  standard  of  0*25  per  cent,  by 
volume,  it  may  be  sometimes  desirable  to  ascertain  the  precise 
amount  of  the  impurity.  This  can  be  done  by  Dr.  Lunge's  t  little 
apparatus  which  I  described  some  years  ago.  I  The  method  was 

*  The  exact  size  should  be  8^5-  oz.,  the  volume  of  air  being  7f  &  oz., 
because  the  lime-water  occupies  ^  oz.  ;  but  an  ordinary  8-oz.  bottle  is 
near  enough  for  the  purpose. 

t  Zur  Fraye  tier  Ventilation,  Zurich,  1877. 

£  C.  Le  Neve  Foster,  "  On  Dr.  Angus  Smith's  Method  of  Testing  the  Air 
of  Mines  and  Dwelling-houses,"  Ann.  Rep.  Hin.  Assoc.  Corn,  and  Devon 
for  1882,  p.  7. 


5°4 


ORE  AND  STONE-MINING. 


originally  suggested  by  Dr.  Angus  Smith,*  and  his  process  consisted 
in  pumping  the  air  of  the  working  place  through  lime-water  until 
a  known  standard  of  milkiness  or  opacity  of  the  solution  was 
attained.  Bad  air  would  cause  the  standard  amount  of  opacity 
with  very  few  strokes  of  the  pump,  whilst  good  air  required  many. 
I  now  find  it  convenient  to  use  lime-water  of  known  strength,  and 
to  go  on  with  the  pumpings  until  the  pink  colour  given  by  phenol - 
phthalein  is  discharged.  This  method  is,  I  consider,  more 
accurate  than  endeavouring  to  reach  the  proposed  standard  of 
milkiness. 

Dr.  Lunge's  apparatus  consists  (Fig.  586)  of  a  No.  i,  or 
i -ounce,  flexible  ball-syringe  A,  connected  by  a  piece  of  india- 
rubber  tube  B,  with  the  bent  glass  tube  D;  at  the  point  C  a 
slit  about  f  inch  long  is  cut  in  the  tube  with  a  very  sharp  knife. 


FIG.  586. 


FIG.  587. 


This  acts  as  a  valve.  The  tube  D  passes  very  little  beyond 
the  cork  of  the  bottle  E,  which  holds  about  two  ounces.  F  is 
a  tube  extending  nearly  to  the  bottom,  connected  by  a  small 
piece  of  india-rubber  pipe  with  the  valve-tube  G,  shown  on 
a  larger  scale  in  Fig.  587.  It  is  simply  a  piece  of  glass  tube,  with 
a  ring  made  of  india-rubber  tube,  supporting  a  glass  valve.  The 
top  part  of  the  valve  is  flat,  not  spherical,  and  it  allows  free' 
passage  of  the  air  when  in  the  position  shown  in  the  figure. 

If  you  squeeze  the  ball  A,  supposing  the  bottle  partly  full  of 
water,  the  valve  in  G  rises  and  prevents  any  escape  of  liquid,  and 
the  air  rushes  out  at  C.  On  allowing  the  ball  A  to  expand  again, 
the  slit  C  closes,  air  enters  through  G,  and  bubbles  up  from  the 
bottom  of  F  into  the  bottle. 

In  order  to  make  the  bottle  as  portable  as  possible,  I  prefer  to 
use  one  piece  of  tube  containing  the  valve  instead  of  having  a- 
separate  valve-tube  as  shown ;  however,  this  is  a  mere  detail  of 
minor  importance. 

*  Op.  cit.,  p.  238. 


VENTILATION.  505 

Half  an  ounce  of  lime-water  or  baryta-water  of  known  strength, 
and  coloured  pink  by  phenolphthalein,  is  put  into  the  bottle ;  the 
ball  is  squeezed  and  allowed  to  expand,  and  a  definite  volume  of 
air  is  drawn  into  the  apparatus.  A  good  shaking  is  given,  and 
continued  long  enough  to  cause  the  absorption  of  all  the  carbonic 
acid  by  the  solution.  This  process  of  squeezing  the  ball  and 
shakiDg  the  bottle  is  repeated  until  the  pink  colour  is  discharged, 
and  knowing  the  strength  of  the  solution  and  the  volume  of  air 
passed  through,  it  is  easy  to  calculate  the  percentage  of  carbonic 
acid  contained  in  the  air. 

Lunge  reckons  that  each  squeeze  of  a  No.  i  ball  causes  the  entry 
of  23  cubic  centimetres  of  air.  The  "  No.  i  "  means  a  one-ounce 
size ;  it  really  contains  about  28  cubic  centimetres,  but  the  whole 
of  this  cannot  be  expelled  by  squeezing.  To  save  the  trouble  of 
making  calculations  each  time,  a  table  should  be  drawn  out  once 
for  all  with  two  columns,  the  first  giving  the  number  of  squeezes, 
and  the  second  the  corresponding  percentages  of  carbonic  acid. 

Further  details  are  given  by  Winkler,*  but  the  form  of  bottle 
shown  by  him,  with  a  long  projecting  valve  tube,  is  not  so  portable 
as  the  one  which  I  use  with  the  valve  contained  in  the  piece  of 
tube  inside  the  bottle.  My  case  is  not  larger  than  a  field-glass, 
and  holds  all  that  is  necessary  for  making  six  determinations 
underground  ;  it  is  most  convenient  to  wear  it  upon  the  belt,  in 
the  same  manner  as  the  "  Tscherpe-Tasche,"  or  pouch  of  the 
Saxon  miner. 

Where  greater  accuracy  is  required,  I  recommend  Hesse's 
apparatus,f  with  which  I  have  made  a  very  large  number  of 
carbonic  acid  determinations  in  the  working  places  of  mines.  The 
leather  case,  which  contains  the  necessary  bottles,  burettes, 
barometer  and  thermometer,  measures  15  inches  by  9^-  by  5. 

Oxygen. — The  unfitness  of  air  for  breathing  is  indicated  not 
only  by  an  excess  of  carbonic  acid,  but  also  by  a  deficiency  of 
oxygen.  When  there  is  both  a  lack  of  oxygen  and  an  undue 
proportion  of  carbonic  acid,  it  is  evident  that  some  process 
of  oxidation  has  been  going  on,  such  as  the  respiration  of  the 
miners,  the  burning  of  candles  or  lamps,  the  slow  combustion  of 
coal  or  pyrites,  or,  lastly,  the  putrefaction  of  timber  or  other 
organic  matter  in  the  mine.  All  four  causes  may  combine  to 
render  the  atmosphere  unhealthy. 

Dr.  Angus  Smith  considers  that  when  the  proportion  of  oxygen 

*  Lehrbuch  der  teckniscken  Gasanalyse,  Freiberg,  1885. 

f  Hesse,  "  Anleitung  zur  Bestimmung  der  Kohlensaure  in  der  Luff, 
nebst  einer  Beschreibung  des  hierzu  nothigen  Apparates."  JEulenbery's 
Vierteljahrsschrift  fur  gericlttliclie  Medicin  und  offentliches  Sanitatswesen , 
Neue  Folge,  vol.  xxxi.,  Berlin,  1879,  p.  357.  Hesse,  " Zur  Bestimmung  der 
Kohlensaure  in  der  Luft,"  Hid.,  vol.  xxxiv.,  I88i,  p.  361.  Winkler, 
Anleitung  zur  chemise/ten  Untersuchung  der  Industrie- Gase,  Freiberg,  1877, 
p.  375.  Winkler,  Lehrbuch  der  technisc/ien  Gasanalyse,  Freiberg,  1885, 
P  67. 


506  ORE  AND  STONE-MINING. 

by  volume  has  been  reduced  below  20*9  per  cent.,  the  atmosphere 
is  impure,  and  when  the  percentage  descends  below  20*6,  he  calls 
it  exceedingly  bad. 

Lindemann's  Apparatus. — For  determining  the  percentage  of 
oxygen  in  the  air  of  mines,  the  simplest  apparatus  is  that  of 
Lindemann,  which  is  figured  and  described  by  Winkler.*  It  is 
based  upon  the  property  possessed  by  moist  phosphorus  of  combining 
with  the  oxygen  of  the  air  at  ordinary  temperatures ;  if  a  large 
surface  of  phosphorus  is  presented  to  the  air,  the  absorption  takes 
place  comparatively  rapidly  at  temperatures  between  60°  and  70°  F. 
(15°  to  20°  C.).  This  apparatus,  and  instruments  of  a  similar 
class  in  which  an  alkaline  solution  of  pyrogallic  acid  is  used 
as  an  absorbent  of  oxygen,  are  better  suited  for  use  in  the 
laboratory  than  for  making  determinations  in  the  mine  itself, 
unless  it  is  desired  to  confine  the  observations  to  one  spot. 
The  box  containing  Lindemann's  apparatus  is  17^  inches  high  by 
i  of  inches  wide,  and  5^  inches  deep,  and  the  weight  when  ready 
for  use  is  8  Ibs.  The  dimensions  and  weight  are  not  prohibitive, 
but  it  would  not  be  safe  to  carry  such  a  box  with  its  glass  vessel 
of  phosphorus  when  climbing  up  stopes  by  a  chain ;  and  there 
are  two  other  important  objections  to  its  use  underground :  (i)  it 
is  difficult  to  manipulate  such  instruments  with  the  dirty  hands 
inevitable  in  mines ;  and  (2)  in  each  working  place  it  would  be 
necessary  to  wait  until  the  whole  of  the  apparatus  had  assumed 
the  temperature  of  the  surrounding  atmosphere,  because  unless 
this  were  done  the  results  would  be  erroneous  from  changes  of 
volume.  However,  it  is  easy  to  bring  up  samples  in  suitable 
glass  bottles,  and  then  submit  them  to  analysis  in  a  laboratory 
above  ground.  The  manipulations  are  not  difficult,  and  any  mine 
agent  capable  of  doing  the  delicate  work  required  for  an.  accurate 
mine  survey  or  the  assay  of  an  ore,  would  find  no  difficulty  in 
making  determinations,  sufficiently  exact  for  his  purpose,  of 
carbonic  acid  and  oxygen  in  underground  air. 

When  the  task  consists  in  determining  the  proportion  of  such 
gases  as  sulphuretted  hydrogen  or  the  quantity  of  organic  matter, 
he  must  call  in  the  services  of  the  chemist. 

MEASURING  THE  QUANTITY  AND  PRESSURE 
OF  THE  AIR. — More  attention  is  paid  by  miners  to  measure- 
ments of  quantity  than  to  determinations  of  quality.  The 
quantity  of  air  passing  through  any  given  passage  can  be  calcu- 
lated by  measuring  its  sectional  area  and  ascertaining  the  speed 
of  the  current.  In  the  old  days  there  were  two  rough  methods 
of  estimating  the  velocity  of  an  air-current:  (i)  by  carrying 
a  candle  in  the  hand  and  regulating  the  pace  so  that  the  flame 
was  not  deflected  either  backwards  or  forwards,  the  rate  of 
walking  was  therefore  precisely  that  of  the  current;  (2)  by 

*  Lehrbuch  der  technischen  Gasanatyse,  Freiberg,  1885,  p.  58. 


VENTILATION.  507 

exploding  a  little  gunpowder  and  observing  how  long  the  smoke 
took  to  travel  along  a  measured  distance  in  a  level.  These 
methods  have  been  abandoned  in  favour  of  speed-measuring 
instruments  known  as  anemometers. 

Anemometers. — Two  kinds  may  be  mentioned  :  fan-plate  type 
and  windmill  type. 

Dickinson's  *  is  one  of  the  former  class  ;  it  consists  of  a  plate 
of  mica,  hung  from  two  fine  bearings,  and  counterpoised  so  that  a 
very  light  breeze  will  deflect  it  from  its  normal  vertical  position. 
The  deflection  is  measured  by  a  quadrant  attached  to  the  frame 
of  the  fan-plate,  and,  instead  of  marking  the  angles,  it  is  usual  to 
show  by  the  graduations  the  velocity  of  the  air  in  feet  per  minute. 
The  instrument  is  graduated  by  actual  experiments  upon  a  test- 
ing machine. 

In  anemometers  of  the  second  type,  the  speed  of  the  air- 
current  is  determined  by  the  number  of  revolutions  of  an 
instrument  provided  with  vanes  like  those  of  a  windmill.  Biram's 
anemometer,  one  very  commonly  used,  has  eight  or  ten  vanes 
made  of  mica  or  vulcanite  or  aluminium,  attached  to  arms  radiating 
from  a  small  central  wheel.  The  instrument  is  held  up  at  arm's 
length  in  the  current,  and  by  the  aid  of  suitable  gearing  and  dials 
and  pointers,  like  those  of  a  gas-meter,  it  registers  either  the 
number  of  its  revolutions,  or  the  rate  in  feet  or  metres  at  which 
the  air  is  travelling,  during  a  short  period  of  time,  measured  by 
a  watch. 

As  a  slow  current  of  air  will  not  make  the  vanes  move  round, 
from  its  being  unable  to  overcome  the  friction  of  the  parts, 
the  makers  usually  supply  a  certificate  with  each  instrument 
showing  what  correction  must  be  made  on  this  account.  The 
correction  is  determined  by  a  testing  machine,  on  which  the 
anemometer  can  be  whirled  round  at  various  rates  of  speed ;  it 
can  then  be  seen  how  far  the  readings  of  the  anemometer  agree 
with  the  known  velocity  at  which  the  whirling  has  been  carried  on. 

Messrs.  Davis  and  Son,  of  Derby,  make  a  self -timing  anemo- 
meter which  dispenses  with  the  use  of  a  watch ;  it  is  held  up  in 
the  current  and  when  the  vanes  are  considered  to  be  revolving  at 
a  constant  speed,  a  catch  is  pressed ;  this  allows  the  vanes  to  act 
on  a  pointer  which  indicates  on  a  dial  the  velocity  in  feet  or  in 
metres  per  second. 

In  making  observations  with  the  anemometer,  it  is  essential 
that  an  airway  of  uniform  section  be  taken ;  levels  which  are 
lined  with  brick  arching  are  well  adapted  for  the  purpose.  If 
the  airway  is  not  regular,  eddies  will  be  set  up  interfering  with 
the  accuracy  of  the  results.  A  further  necessary  precaution  is 
taking  observations  in  various  parts  of  the  area  chosen  for 
the  experiment,  because  the  velocity  is  not  uniform  through- 

*  Dickinson,  "On Measuring  Air  in  Mines,"  Trans.  Manchester  Geol.  Soc., 
vol.  xiv.,  1878,  p.  31. 


ORE  AND  STONE-MINING. 


out  this  area.  The  mean  of  the  readings  gives  the  mean  velocity 
of  the  current.  In  the  instructions  laid  down  by  a  committee 
appointed  by  three  of  the  British  Mining  Institutes,*  the  area  at 
which  the  observations  are  made  has  to  be  divided  up  by  horizontal 
and  vertical  strings  into  sixteen  equal  parts,  and  a  reading  of  the 
anemometer  taken  in  each. 

Water- Gauge. — For  calculating  the  efficiency  of  the  venti- 
lating machinery,  a  mere  knowledge  of  the  volume  of  air  passed 
through  the  workings  does  not  suffice ;  in  addition,  its  pressure 
has  to  be  determined,  or  rather  the  difference  between  its 
pressure  and  that  of  the  external  atmosphere. 

The  instrument  employed  for  this  purpose  is  the  manometer, 
or  water-gauge.  It  is  a  glass  tube  bent  in  the  form  of  a  U,  partly 
filled  with  water;  one  leg  is  in  communication  with  the  outer 
atmosphere  and  the  other  with  that  of  the  mine.  Usually  it  is 
placed  in  the  engine-house  of  the  fan,  and  a  pipe  is  carried 
from  it  into  the  fan  drift.  The  suction  of  the  fan  causes  the 
pressure  of  the  air  in  the  mine  to  be  less  than  that  of  the  external 
atmosphere,  and  the  diminution  of  pressure  is  indicated  by  the 
difference  in  the  heights  of  the  two  columns  of  water  in  the  U-tube, 
The  manner  in  which  a  water-gauge  acts  can 
easily  be  explained  to  students  by  construct- 
ing a  model  from  a  Woulff's  bottle  (Fig.  588), 
or  any  other  bottle  or  jar  which  will  take 
three  pieces  of  glass  tube.  If  the  mouth  is 
applied  to  the  piece  of  india-rubber  tube  A, 
air  can  be  drawn  through  the  bottle  in  the 
direction  indicated  by  the  arrows.  With  a 
certain  degree  of  suction,  the  resistance 
caused  by  the  passage  through  the  tube  B 
becomes  plain,  and  a  strong  air  current  is 
not  produced  until  the  external  pressure  is 
decidedly  greater  than  that  inside  the  bottle, 
which  is  indicated  by  the  rise  of  the  coloured 
water  in  the  gauge  C,  as  shown  in  the  figure. 

In  the  instruments  employed  in  mines,  the  difference  in 
pressure  is  measured  by  a  scale  which  can  be  moved  up  and  down 
by  a  screw,  so  as  to  make  the  zero  correspond  with  the  level  of 
the  water  in  the  free  limb.  It  usually  varies  from  i  to  4 
inches.  In  order  to  prevent  the  water  in  the  gauge  from 
oscillating  rapidly  up  and  down,  which  would  happen  if  the 
current  were  irregular,  the  tube  connecting  the  two  upright 
limbs  is  contracted,  or,  what  comes  to  the  same  thing,  the  gauge  is 

*  Joint  Committee  of  the  North  of  England  Institute  of  Mining  and 
Mechanical  Engineers,  Midland  Institute  of  Mining,  Civil,  and  Mechanical 
Engineers,  and  the  South  Wales  Institute  of  Engineers,  "  On  Mechanical 
Ventilators,  1888,"  "  Observations  to  be  Made,  and  Instructions  to  the 
Engineers."  Trans.  N.  E.  Inst.  H.  M.  Eny.,  vol.  xxxvii.,  1887-8,  p.  190. 


VENTILATION.  509 

made  in  the  form  of  two  chambers  with  a  glass  front  and  a  connect- 
ing aperture,  the  size  of  which  can  be  regulated  by  a  tap.  This 
is  Dickinson's  water-gauge,*  which  is  a  brass  box  6  inches  high, 
4  inches  wide,  and  3  inches  deep,  with  a  partition  in  the  middle, 
making  two  chambers  each  2  inches  by  3  inches.  A  glass  front 
shows  the  two  columns  of  water,  and  a  scale,  graduated  into 
inches  and  tenths,  enables  the  difference  in  their  heights  to  be 
measured. 

Efficiency  of  Ventilating  Appliances. — The  efficiency  of 
a  fan  or  other  ventilator  is  calculated  by  comparing  the  work 
which  it  does  in  drawing  air  through  the  mine,  with  the  work  done 
by  the  steam  in  moving  the  piston  of  the  engine  that  drives  it. 

The  work  done  in  moving  air  is  reckoned  from  the  volume 
displaced  and  the  pressure ;  the  former  is  ascertained  by  the 
anemometer  and  the  latter  by  the  water-gauge.  As  a  cubic  foot 
of  water  weighs  62*425  -pounds,  each  inch  indicated  by  the  water- 
gauge  will  represent  pressure  of  one-twelfth  of  this  amount,  or  5-2 
pounds  per  square  foot.  A  depression  of  the  water-gauge  of  2  inches 
will  mean  2  x  5*2  or  10*4  pounds  pressure  per  square  foot.  In 
common  parlance  the  word  "  depression "  is  understood,  and 
the  miner  speaks  of  a  "  water-gauge "  of  2  inches,  for  instance, 
meaning  thereby  a  depression  of  the  water-gauge. 

The  work  done  is  looked  upon  as  that  of  pushing  a  volume  of 
air  through  a  pipe  under  the  pressure  indicated  by  the  water- 
gauge.  Let  A  represent  the  area  of  the  airway  in  square  feet,  Y 
the  velocity  of  the  air  current  in  feet  per  minute,  as  measured  by 
the  anemometer,  Wthe  water-gauge  in  inches,  5*2  pounds  being 
the  weight  of  a  column  of  water  one  inch  high  with  an  area  of 
i  square  foot,  E  the  useful  effect  of  the  ventilator. 
Then 

E  =  (A  V  W  x  5*2)  foot-pounds  per  minute. 

To  ascertain  the  horse-power  it  is  only  necessary  to  divide  by 
33,000,  and  we  may  state  : 

E  =  AVWx  5-2  H.  p 

33,ooo 

Thus  to  take  an  example  : 

If  the  quantity  of  air  in  circulation,  A  V,  is  100,000  cubic  feet 
per  minute,  the  water-gauge  1*5  inches,  the  useful  effect  of  the 
ventilation  will  be : 

100,000  x  i -5  x  5-2  =       6    H  p 
33,ooo 

The  efficiency  of  the  ventilating  plant  is  the  ratio  of  the  horse- 
power of  the  ventilation  so  calculated  to  the  indicated  horse- 
power of  the  driving  engine. 

*  Dickinson,  op.  cit.,  p.  12. 


510  ORE  AND  STONE-MINING. 

Supposing  that  the  indicated  horse-power  was  found  to  be  45  T 
we  should  have  the  ratio  of  23*63  to  45  as  denoting  the  efficiency. 
In  other  words  : 

Efficiency  =  2-3_J*=  -5251  or  52-51  per  cent, 

45 

Resistance  caused  by  Friction.  —  The  amount  of  power 
required  to  overcome  the  friction  of  the  air  current  in  passing 
through  the  passages  of  the  mine  must  be  studied,  because  it  is 
an  important  factor  in  the  problem  of  ventilation  ;  and  unless  its 
effects  are  appreciated  the  best  method  of  arranging  the  ventila- 
tion will  not  be  understood. 

The  amount  of  friction  depends  upon  five  conditions  : 

1.  The  length  of  the  airway,  which  we  may  call  L. 

2.  The  perimeter  of  the  airway,  P. 

3.  The  sectional  area  of  the  airway,  A. 

4.  The  velocity  of  the  current,  V. 

5.  The  nature  of  the  rubbing  surface,  the  effect  of  which  may  be 

expressed  by  a  co-efficient  C. 

The  friction  is  directly  proportional  to  the  length  of  the  airway 
and  its  perimeter;  in  other  words,  if  there  is  twice  as  much 
rubbing  surface,  there  is  twice  as  much  friction.  It  is  inversely 
proportional  to  the  sectional  area  of  the  airway  —  that  is  to  say,  a 
level  7  feet  high  and  10  feet  wide  will  cause  only  one-half  of  the 
friction  produced  in  a  level  of  the  same  height,  but  5  feet  wide. 
Lastly,  the  friction  increases  as  the  square  of  the  velocity. 
These  relations  may  be  expressed  by  the  general  formula  : 

Eesistance  due  to  friction  =  C  L  F  ^ 


It  is  evident  from  this  formula  that  it  is  desirable  to  shorten 
the  path  of  the  air  as  far  as  possible;  much  is  done  in  this 
direction  nowadays  by  "  splitting"  the  air  current  —  that  is  to  say, 
dividing  it  into  separate  branches  instead  of  causing  the  whole 
of  the  current  of  the  downcast  shaft  to  travel  through  the  entire 
length  of  the  workings, 

With  regard  to  the  second  factor,  the  perimeter,  it  may  be 
well  to  notice  that  a  circular  section  is  the  one  with  which  a  given 
length  of  perimeter  affords  the  largest  area.  Take,  for  instance, 
the  case  just  cited  of  a  rectangular  airway,  7  feet  high  by  5  feet 
wide,  with  a  perimeter  of  24  feet  and  an  area  of  35  square  feet. 
A  circle  having  a  circumference  of  24  feet  would  have  an  area  of 
45  '8  square  feet,  or  30  per  cent,  more  than  the  rectangle. 

Splitting  has  also  the  effect  of  reducing  the  velocity  required 
for  the  passage  of  a  given  quantity  of  air  through  the  mine. 
Suppose  that  90,000  cubic  feet  are  wanted  per  minute  in  order 
to  ventilate  the  mine  ;  if  the  mine  is  divided  into  three  equal 
and  similar  districts  and  each  is  ventilated  separately  by  one- 


VENTILATION.  511 

third  of  the  main  current,  the  velocity  of  the  minor  currents 
need  be  only  one- third  of  what  would  have  been  necessary  if  all 
the  air  had  had  to  travel  by  one  road.  Reducing  the  velocity 
to  one-third  means,  according  to  the  formula,  a  diminution  of  the 
resistance  caused  by  friction  to  one-ninth. 

The  co-efficient,  C,  varies  according  to  the  nature  of  the 
rubbing  surface ;  in  smooth  passages,  such  as  those  of  levels  lined 
by  an  arching  of  brick,  it  will  naturally  be  less  than  in  the 
irregular  airways  along  the  working  face,  or  in  an  airway  with 
frames  of  timber,  forming  a  succession  of  projecting  obstacles  at 
short  intervals. 

FIG.  589. 


0-5 


If  the  resistance  due  to  friction,  or,  in  other  words,  the  pressure 
required  to  overcome  it,  is  measured  in  pounds  per  square  foot, 
then  taking  L  and  P  in  feet,  Y  in  thousands  of  feet  per  minute, 
and  A  in  square  feet,  the  co-efficient  C  varies  from  0*002  to  0*014* 
according  to  the  nature  of  the  airway. 

Mining  engineers  owe  a  debt  of  gratitude  to  M.  Murgue  t  for 
his  graphic  representation  (Fig.  589),  which  illustrates  the  influ- 

*  Elwen,  "  An  Account  of  Experiments  on  the  Resistance  to  Air  Currents 
in  Mines,"  and  Walton  Brown  in  the  discussion.  Trans.  N.  E.  Inst.  M.  E.t 
vol.  xxxviii.,  1888-9,  P-  205-218. 

f  "  Recherches  Experimentales  sur  la  Perte  de  Charges  dans  les  Parcours 
Souterrains,"  Bull.  Soc.  Ind.  Min.,  vol.  vii.,  1893,  p.  5  ;  and  translation  in 
Trans.  Amer.  Inst.  M.  E.t  vol.  xxii.,  1893-1894. 


512  ORE  AND  STONE-MINING. 

ence  of  the  sides  of  an  airway  in  a  most  striking  fashion.  He 
compares  three  kinds  of  airways  :  one  arched,  ABC;  a  second, 
D  E  F  G,  in  bare  rock  ;  and  a  third,  H  I  J  K,  lined  with  timber ; 
and  he  shows  that,  with  the  dimensions  given  in  the  figure,  all 
three  airways  produce  the  same  amount  of  friction,  or  cause  the 
same  loss  of  "  head."  In  other  words,  the  arched  passage  ABC, 
in  spite  of  its  small  dimensions,  offers  no  greater  resistance  to  the 
air  current  than  the  large  timbered  tunnel  H  I  J  K  ;  whilst  you 
may  put  the  brick  lining  ABC  inside  a  level  D  E  F  G  without 
in  any  way  requiring  additional  ventilating  power.  He  concludes 
that  it  is  more  important  to  diminish  the  friction  in  the  air- 
passages  than  to  seek  for  .better  ventilators,  and  that  the  miner 
can  lessen  the  resistance  to  air-currents  not  only  by  increasing 
the  size  of  his  levels,  but  also  by  lining  them  with  brick  or  stone 
in  place  'of  timber,  and  by  keeping  them  as  straight  as  possible. 


CHAPTER  XI. 

LIGHTING. 

Keflected  daylight — Candles,  candle-holders — Lamps  and  lamp  oil — Wells 
light — Magnesium  wire — Safety  lamps  :  Davy,  Clanny,  Mueseler, 
Marsaut,  Hepple white- Gray — Locks:  lead  rivet,  magnetic  bolt, 
Cuvelier's  lock — Coal  gas — Electricity. 

MIXES  are  usually  lighted  by  candles,  torches,  lamps,  gas,  or 
electricity. 

In  a  few  cases  the  miner  does  his  work  without  artificial  light. 
In  sinking  oil-wells  in  Burma,*  the  quantity  of  explosive  gas  is 
so  great  that  no  naked  light  can  be  used,  and  even  if  the  work- 
man had  a  safety  lamp,  he  would  be  unable  to  stay  below  ground 
long  without  being  affected  by  the  noxious  atmosphere.  He 
therefore  carries  no  light  at  all,  and  has  his  eyes  bandaged  up 
before  he  goes  down,  because  otherwise  it  would  take  longer  for 
his  eyes  to  become  accustomed  to  the  semi-darkness  of  the  bottom 
of  the  pit,  than  the  whole  time  he  can  stay  below  ground. 

Reflected  Daylight. — For  sinking  oil-wells  in  Japan  t 
reflected  daylight  is  used.  A  piece  of  yellowish  translucent  oil- 
paper, about  5  feet  by  3  J  feet,  is  suspended  over  the  well  at  an 
angle  of  45°  and  throws  fight  down  the  pit.  The  wells  are  about 
3!  feet  square,  and  are  dug  to  a  depth  of  600  to  900  feet. 

In  driving  the  Bell  tunnel  at  the  New  Idria  quicksilver  mine,J 
in  California,  there  was  a  disastrous  explosion  from  the  igni- 
tion of  some  inflammable  gas,  and  after  this  occurrence  the 
tunnel  was  lighted  by  the  reflection  of  the  sun's  rays.  A  mirror 
was  kept  at  the  mouth  of  the  drift  at  the  proper  angle  to  effect 
this,  and  with  a  straight  tunnel  and  in  a  sunny  country  like 
California  the  device  answered  perfectly. 

Candles. — The  candles  used  by  miners  are  very  frequently 
the  so-called  "  dips  " — that  is  to  say,  they  are  made  by  dipping  a 
wick  into  molten  tallow  and  allowing  it  to  take  up  grease;  the 
process  is  repeated  several  times,  until  the  thickness  of  tallow  is 
sufficient.  The  wick  is  made  of  cotton,  or  of  cotton  and  linen. 

*  Noetling,  liec.  Geol.  Surrey  India,  vol.  xxii.,  1889,  P-  97- 

t  Redwood,  "Petroleum  and  its  Products,"  Jour.  Soc.  Arts,  voL  xxxiv., 

1886,  p.  832. 
J  Becker,  "  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope," 

Mon.  U.S.  Geol  Survey,  vol-  xiii.,  1888,  p.  308. 

2  K 


514  ORE  AND  STONE-MINING. 

At  Snailbeach  Mine,  in  Shropshire,  the  manager  stipulates  that 
the  wick  shall  be  made  of  three  threads  of  cotton  and  three  of 
linen ;  this  is  folded,  and  the  candle  therefore  has  a  wick  of  six 
threads  of  cotton  and  six  of  linen. 

The  size  of  the  candles  is  reckoned  by  the  number  that 
go  to  a  pound,  which  varies  from  20  to  6.  Candles  of  six- 
teen to  the  pound  are  very  commonly  used  by  the  miners,  while 
the  agents,  who  want  an  extra  amount  of  light  for  their  exam- 
inations, find  it  convenient  to  have  "eights"  and  occasionally 
"  sixes."  These  candles  require  snuffing  from  time  to  time, 
though  I  have  seen  snuffless  dips  employed  in  exceptional  cases. 
In  hot  mines  special  dips  are  necessary,  for  those  made  of 
ordinary  tallow  become  soft  and  bend  down. 

As  a  rule  the  British  ore-miner  holds  his  candle  in  a  lump  of 
clay,  which  forms  a  very  convenient  support.  It  has  the  advan- 
tage that  the  candle  can  be  stuck  up  at  any  point  where  it  is  wanted, 
without  a  moment's  delay  in  seeking  for  a  place  to  fix  it ;  it  is  also 
readily  stuck  upon  the  hat  when  the  miner  wants  to  climb  a  ladder 
or  a  chain.  But  the  clay  must  be  soft,  well  kneaded,  and  free  from 
stones  or  lumps ;  from  time  to  time  it  has  to  be  moistened,  and 
care  and  practice  are  required  in  order  to  work  it  down  properly 
as  the  candle  is  consumed. 

In  the  Forest  of  Dean  many  years  ago,  the  candle  was  stuck 
into  a  cleft  stick,  which  was  carried  in  the  mouth.  Nowadays  metal 
candle-holders  are  used  instead,  with  a  point  which  can  be  stuck 
into  the  timber  or  a  crevice  in  the  rock. 

The  tallow  candle  has  the  disadvantage  of  guttering  in  a 
draught  and  of  causing  a  good  deal  of  smoke,  which  is  bad  if  the 
working  place  is  at  all  close.  The  Festiniog  men  guard  their  candles 
against  draughts,  when  walking  to  and  from  their  work,  by  shades 
made  out  of  old  meat-tins  with  a  handle  of  wire.  If  there  is 
much  water  dropping  down  a  shaft  the  miner  can  protect  his. 
candle  by  a  shield  of  tin-plate  nailed  to  a  piece  of  wood. 

Grease  is  bad  for  amalgamation,  and  sperm  candles  are  adopted 
in  some  gold  mines,  as  they  are  less  objectionable  than  those  made 

of  tallow.     Paraffin,  stearine 

FIG.  590.  and  "composite"  candles  may 

be  and  are  used  in  place  of  the 
common  dip;  they  do  not 
stand  a  strong  draught  or 
drops  of  water  so  well  as  the 
latter,  but  they  give  less  smoke 
_  and  do  not  gutter  so  much. 

JJZ§)         Moulded  candles  are  conve- 
niently carried  by  a    holder,. 

such  as  is  seen  in  the  United  States,  made  of  a  small  rod  of  iron 
with  one  end  bent  into  a  handle  and  the  other  pointed  (Fig.  590). 
In  the  middle  there  is  a  cylinder  of  thin  sheet  iron  which  has 


LIGHTING. 


spring  enough  to  clip  the  candle  firmly ;  a  sharp  hook,  sticking 

up  at  right  angles  to  the  horizontal  rod,  enables  the  holder  to  be 

hung  on  to  the  slightest  little  projection,  if  there  is  no  convenient 

crevice  or  piece  of  timber  into  which  its  point  can  be  thrust.    The 

Australian  has  a  somewhat  similar  holder  made  of  wire,  known  as 

the  "  spider."*     The  wire  is  about  one-sixteenth  of  an  inch  thick, 

twisted  as  shown  (Fig.  591); 

the  spiral  portion    holds   the  FIG.  591. 

candle,  and  the  little  hook  will 

hang   on   to   the  face  of  the 

rock. 

A  candle-holder  of  some 
kind  is  more  convenient  to  an 
official  who  has  to  make  notes 
underground,  than  the  usual 
lump  of  clay  ;  with  the  latter 
it  is  difficult  to  keep  the  note- 
book clean. 

Torches. — Torches  are  em- 
ployed in  a  few  exceptional 
instances.  The  foremen  at 
Falun,  in  Sweden,  carry 
torches  consisting  of  bundles 
of  pine  sticks  held  together 

by  an  iron  ring,  and  some  gold  mines  in  Japan  f  were  lighted  a 
few  years  ago  by  torches  made  of  dried  bamboo  twigs ;  fires  of 
pitch- wood  have  been  used  at  night  when  washing  down  gravel 
by  the  hydraulic  process. £  Large  underground  chambers  may  be 
lit  up  for  a  short  time,  in  order  to  examine  the  roof,  by  burning 
a  bundle  of  wood  shavings  soaked  with  naphtha  and  petroleum. 

Lamps. — Lamps  vary  much  in  shape  and  size.  The  Sicilian 
miner  has  a  lamp  of  the  simplest  construction  imaginable ;  it  is  a 
mere  open  cup  of  unglazed  pottery,  about  2  inches  in  diameter 
and  i  inch  deep,  with  a  little  lip  for  holding  a  cotton  wick,  which 
lies  loosely  in  the  olive  oil  used  as  an  illuminant.  It  is  ruder 
than  the  old  Roman  lamps  found  at  Pompeii,  which  somewhat 
resemble  those  still  employed  in  the  Hartz.  The  latter  are 
provided  with  a  hook,  by  which  they  can  be  held  between 
the  thumb  and  forefinger  when  climbing  ladders;  the  hook 
has  a  sharp  point  which  the  miner  can  stick  into  a  timber 
prop  or  a  crevice  in  the  rock  while  at  work.  The  body  of  the 
lamp  is  closed  ;  it  has  a  tube  for  the  cotton  wick  and  a  hole  with 
a  screw-plug  through  which  the  supply  of  oil  can  be  replenished. 

*  Annual  Eeport  of  the  Secretary  for  Mines,  Victoria,  for  the  year  1 888, 
Melbourne,  1889,  p.  36. 

t  Frecheville,  "  The  Mining  and  Treatment  of  Gold  Ores  in  the  North . 
of  Japan,"  Min.  Proc.  Inst.  C.E.,  vol.  Ixxv.,  1883-84,  p.  169. 

J  Bowie,  Hydraulic  Mining  in  California,  New  York,  1885,  p.  246. 


516  ORE  AND  STONE-MINING. 

A  pricker  for  trimming  the  wick  is  attached  by  a  light  chain.  A 
smaller  but  similar  lamp  is  met  with  in  France,  northern  Italy, 
and  parts  of  Spain ;  the  body  is  lenticular,  and  is  suspended  by  a 
long  hook. 

The  foremen  in  the  Hartz  mines  prefer  a  somewhat  similar  lamp 
in  which  they  can  burn  tallow ;  it  is  an  open  tray  with  a  rim 
around  it  and  a  lip  for  the  cotton  wick ;  a  large  lump  of  tallow 
lies  in  the  lamp  at  the  opposite  side  to  the  wick,  and  if  the  agent 
wishes  to  make  a  flare-up,  to  illuminate  a  working  place  more 
thoroughly,  he  need  only  push  a  good  supply  of  tallow  towards  the 
wick  holder,  and  soon  obtains  the  desired  effect. 

In  the  Mansfeld  copper  district  the  miner  has  a  small  tin  lamp 
which  can  be  hung  by  a  wire  loop  to  a  hook  on  the  hat,  if  he  is 
climbing,  or  be  placed  upon  the  ground  in  the  working  place.  It 
has  a  double  case,  the  outer  one  serving  to  catch  any  oil  which 
may  run  over  from  the  spout-like  wick-tube. 

The  Saxon  miner  still  adheres  to  the  "  Blende,"  a  wooden  case 
lined  with  tin-plate  or  brass,  in  which  he  carries  a  small  globular 
oil  lamp.  The  case  is  useful  in  walking  or  climbing  in  very 
draughty  parts  of  the  mine,  and  can  be  hung  from  the  neck  by  a 
leather  strap. 

In  Scotland  and  in  some  parts  of  the  United  States,  a  small  but 
serviceable  tin  lamp, of  the  shape  shown  in  Fig.  592,13  very  common. 
It  can  be  hooked  on  to  the  hat  when  climbing 
FIG.  592.         ladders,  or  on  to  the  rock.    Olive  oil  or  rape  oil  is 
burnt  in  the  lamps  just  described,  and  the  miner 
carries  with  him  a  supply  in  a  little  flask. 

Lamps  have  the  advantage  of  being  cheaper 
and  cleaner  than  tallow  candles,  but  the  latter 
do  not  seem  likely  to  be  displaced  in  English  and 
Welsh  ore  mines,  though  the  Scotch  lead  miner 
prefers  the  former. 

Mineral  oils  are  occasionally  used  instead  of 
vegetable  oils  for  ordinary  miners'  lamps.  At  the  underground 
stone  quarries  near  Bath  the  men  employ  small  lamps  fed  by  ben- 
zoline,  which  is  held  by  a  sponge  in  the  reservoir.  Petroleum 
"Hurricane"  lamps  for  lighting  up  pit-bottoms  and  landings 
(plats)  are  not  uncommon,  and  even  levels  are  lit  up  in  this  way 
by  hanging  a  lamp  at  each  bend  in  the  road.  This  saves  the 
miner  the  trouble  of  carrying  a  lamp,  and  the  light  is  quite 
sufficient  for  the  purpose  of  tramming,  even  if  the  stretches  are 
somewhat  long. 

Flare  lamps,  similar  to  those  used  by  "  Cheap  Jacks,"  which 
generate  gas  from  naphtha,  or  a  mixture  of  naphtha  and 
petroleum,  flowing  into  a  hot  burner,  may  occasionally  be  seen 
in  parts  of  underground  slate  quarries,  where  a  good  deal  of  light 
is  required  for  hooking-on  and  unhooking  waggons. 

Wells  Light. — Among  recent  inventions  for  illuminating,   I 


LIGHTING. 


must  specially  mention  the  Wells  light,  which,  after  being  largely 
used  for  surface  works,  is  now  finding  applications  underground. 
The  Wells  light  is  a  contrivance  for  burning  tar  oils  converted 
into  gas,  when  forced  through  a  heated  burner  by  pressure  pro- 
duced by  a  hand  air-pump. 

Fig.  593  shows  the  principal  parts  of  the  lamp,  A  is  a  closed 
cylinder  made  of  steel  boiler  plate,  B  is  a  pump  worked  by  the 
handle  C,  which  can  be  used 
for  pumping  in  either  air  or 
oil ;  whilst  the  light  is  run- 
ning, the  oil  is  drawn  from  a 
bucket  by  the  piece  of  hose 
D.  E  is  the  oil  which  has 
been  pumped  in,  thereby 
compressing  the  air  above  it 
to  about  20  Ibs.  per  square 
inch.  On  turning  the  tap  G, 
the  oil  is  forced  up  the  pipe 
H  to  the  generating  tubes 
I  I,  which  have  been  pre- 
viously heated  by  lighting 
some  cotton  waste  and  oil  in 
the  tray  K.  The  prelimi- 
nary  heating  may  also  be 
effected  by  burning  a  spray 
of  the  oil,  produced  by  a 
special  starting  appliance 
forming  part  of  the  lamp. 
The  oil  in  its  passage  through 
the  hot  burner  I  is  converted 
into  vapour,  which  issues 
forth  from  the  nozzle  L  and 
produces  a  flame  of  1 2  to  30 
inches  in  length,  with  a  con- 
sumption of  half  a  gallon  to 
J2"  galloris  °f  °il  per  hour, 
giving  a  light  of  500  to  4000 
candles.  O  is  a  plug  con- 
nected to  a  rod  which  serves 

the  double  purpose  of  letting  off  the  air  quickly  at  any  time, 
and  also  of  gauging  the  depth  of  the  oil  in  the  cylinder. 

The  lamp  is  easily  carried  about  from  place  to  place.  The 
smallest  size  and  the  larger  one,  No.  3,  have  both  been  employed 
of  late  in  the  large  chambers  of  the  Festiniog  slate  mines  for 
examining  the  roof  and  sides,  and  also  for  plate-laying.  The 
pressure  of  the  air  in  the  reservoir  is  kept  up  by  a  few  strokes  of 
the  pump  from  time  to  time.  ;  •  : 

The  brilliant  light  emitted  by  burning  magnesium  is  utilised  at 


518  ORE  AND  STONE-MINING. 

Festiniog,  in  addition  to  the  "Wells  light,  for  examining  the 
underground  chambers.  The  agents  of  some  of  the  mines 
carry  a  little  stock  of  magnesium  ribbon  in  their  pocket-books, 
and  set  fire  to  a  piece  if  they  wish  to  throw  a  powerful  light  upon 
any  particular  spot  which  may  require  special  attention.  At 
two  of  the  mines  the  metal  is  burnt  in  a  special  lamp.  It 
consists  of  a  coil  of  magnesium  ribbon  about  J  inch  wide  wound 
upon  a  reel,  which  is  fed  by  clock-work,  so  that  it  issues 
from  a  tube  at  the  focus  of  a  silvered  mirror  about  8  inches  in 
diameter.  The  lamp  is  held  by  a  convenient  handle,  and  the  light 
can  be  directed  on  to  any  given  point  without  dazzling  the  eyes. 
The  ribbon  is  consumed  at  the  rate  of  about  i  o  inches  per  minute ; 
the  lamp  can  be  started  and  stopped  by  touching  a  catch  which 
controls  the  clock-work,  and  there  are  means  of  altering  the  speed 
at  which  the  ribbon  is  fed  forwards. 

Safety  Lamps. — The  subject  of  safety  lamps — that  is  to  say, 
lamps  which  can  be  used  in  an  atmosphere  containing  a  certain 
amount  of  inflammable  gas  without  fear  of  causing  an  explosion 
— may  seem  out  of  place  to  some  who  suppose  that  their 
use  is  confined  to  coal  pits :  but  when  we  recollect  that  fire- 
damp has  been  met  with  in  mines  worked  for  diamonds,  gold, 
iron,  lead,  quicksilver,  salt,  silver,  sulphur,  and  tin,  and 
further  that  a  lead  mine  in  this  country  is  lighted  entirely 
with  such  lamps,  and  that  they  are  indispensable  in  the 
case  of  ozokerite,  it  is  evident  that  miners  generally  should 
have  some  knowledge  of  the  principles  upon  which  they  are 
constructed,  and  the  manner  in  which  they  are  used.  However, 
in  the  mines  with  which  we  are  dealing,  safety  lamps  are  the 
exception,  and,  therefore,  the  subject  can  be  dealt  with  in  a 
summary  manner. 

The  construction  of  the  safety  lamp  is  based  upon  the  fact 
that  gauze  of  a  certain  mesh,  made  with  wire  of  a  certain  gauge, 
is  capable  of  cooling  burning  gases  to  a  point  below  that  at 
which  combustion  will  take  place — in  other  words,  it  will  pre- 
vent the  passage  of  flame.  Therefore,  when  a  lamp  enclosed  in  a 
suitable  cylinder  of  this  gauze  is  placed  in  an  atmosphere  con- 
taining fire-damp,  the  inflammable  gas  inside  the  envelope  will 
burn  without  igniting  that  which  is  outside. 

I  will  now  describe  briefly  the  lamps  most  commonly  in  use  in 
mines  containing  inflammable  gas ;  they  are  named  after  their 
inventors,  viz.,  the  Davy,  Clanny,  Mueseler,  Marsaut,  and  Hepple- 
white-Gray  lamps. 

The  ordinary  Davy  lamp  (Fig.  594)*  consists  of  a  brass  oil 
vessel  b,  on  to  which  is  screwed  a  cylinder  of  wire  gauze  a, 
about  i^  inches  in  diameter  and  4^  to  5^  inches  high.  The 

*  The  materials  used  in  constructing  the  lamps  are  indicated  thus  : 


J3rvtss  W  Thtn  STicctMetctl/ 


LIGHTING. 


FIG.  595. 


cylinder  is  further  closed  at  the  top  by  a  cap  of  wire  gauze  e, 

which  overlaps  the  main  gauze  for  a  distance  of  i   inch  to  ij 

inches.     In  the  centre  of  the  oil-vessel  is  a  round  tube  containing 

a  cotton  wick,  which  can  be  trimmed  from  the  outside  by  a  piece 

of  wire  f  passing  up  through  the  bottom.     The  gauze  used  has 

28  holes  or  meshes  per  linear  inch,  or,  in  other  words,  784  per 

square    inch.     The  wire  varies  slightly  in  size;   some  which    I 

very   carefully   measured   was    "016   inch  in  diameter,  and  was 

probably    intended    for    No.    27    S.W.G.      A  maker  of  repute 

informs  me  that  he  usually 

employs  No.    30   of  the  old 

B.W.G.     Speaking   roughly, 

the  holes  are  -^  incn  (k  mm-) 

square.  Three  rods  c, attached 

oelow  to   a  ring  screwed  on 

to  the  oil-vessel  and  above  to 

n  plate,  protect  the  gauze  to 

a  certain  extent.     The  lamp 

is  carried  by  a  strong  wire 

ring    fastened    to    the     top 

plate  d.     Rape,  colza,  or  seal 

oil,  alone  or  with  the  addition 

of  petroleum,  are  used  as  il- 

luminants. 

The  Davy  lamp  has  several 
grave  defects :  in  the  first 
place  it  gives  very  little  light ; 
and  secondly,  as  pointed  out 
by  the  Royal  Commission  on 
Accidents  in  Mines,*  it  will 
fire  an  explosive  mixture  if 
the  velocity  of  the  current  exceeds  6  feet  a  second.  According  to 
the  photometric  tests  made  for  the  Royal  Commission  by  Professor 
Clifton,t  the  light  of  the  Davy  lamp  varied  1'rom  7  to  22  percent, 
of  that  of  a  standard  candle  ;  these  were  laboratory  experiments, 
in  which  the  light  was  not  further  diminished  by  the  accumula- 
tion of  dirt,  grease,  soot,  and  coal  dust  upon  the  gauze,  as  may 
often  happen  underground,  and  nothing  is  said  about  the  absence 
of  illumination  immediately  above  the  lamp. 

With  the  powerful  ventilating  currents  in  use  nowadays,  the 
second  defect  is  a  very  real  one  ;  it  is  sometimes  overcome  by  placing 
the  Davy  lamp  in  a  cylindrical  tin  case  with  a  glass  window. 

It  was  very  natural  to  attempt  to  remedy  the  first  defect  of 
the  Davy  lamp  by  using  glass  instead  of  gauze,  for  the  lower  part 
of  the  enclosing  cylinder. 

In  the  Clanny  lamp  (Fig.  595),  constructed  upon  this  principle, 

*  Preliminary  Report,  1881,  p.  xiii. 

t  Final  Report,  1886,  Appendix  xxiv.,  p.  87. 


52° 


OKE  AND  STONE-MINING. 


FIG.  596. 


the  air  which  feeds  the  flame  comes  in  through  the  gauze  just  above 
the  glass  a,  descends  along  its  inner  face  and  goes  to  the  wick ; 
the  products  of  combustion  then  pass  up  the  centre.  Nothing 
separates  the  descending  current  of  air  from  the  ascending  current, 
and  consequently  the  oil,  from  want  of  a  direct  supply  of  fresh 
air,  does  not  always  burn  so  brightly  as  it  does  in  a  lamp  fed 
from  under  the  gauze ;  but  the  light  is  far  better  than  that  of 
a  Davy  lamp.  The  letter  b  represents  one  of  the  metal  rods  for 
protecting  the  glass.  Professor  Clifton's  experiments  usually 
gave  26  to  50  per  cent,  of  the  light  of  a  standard  candle,  or,  on 
an  average,  more  than  twice  as  much  light  as  the  Davy.  In  a 
current  having  a  velocity  of  more  than  6  feet  a  second  it  behaves 
like  the  Davy,  and  ignites  an  explosive  mixture. 

Mueseler's  lamp  (Fig.  596)  may  be  conveniently  described  as  a 
Clanny  lamp,  with  a  chimney  a  fixed  above  the  flame,  and  attached 
at  the  level  of  the  top  of  the  glass  to  a  dia- 
phragm or  horizontal  partition  of  wire  gauze 
6.  The  path  taken  by  the  air  is  shown  by 
the  arrows.  The  fact  of  the  inward  current  of 
fresh  air  being  kept  separate  from  the  outward 
current  of  foul  air  assists  the  illuminating 
power  of  the  lamp.  The  wick  is  sometimes 
flat. 

The  Mueseler  lamp,  which  is  the  only  one 
allowed  in  fiery  pits  in  Belgium,  is  a  favour- 
ite in  many  countries,  and  leaving  aside  its 
use  in  collieries,  I  may  mention  that  it  is  the 
only  lamp  employed  at  the  very  dangerous 
ozokerite  mines  of  Boryslaw  and  at  the  Mill 
Close  lead  mine  in  Derbyshire.  It  has  the 
merit  of  going  out  in  an  explosive  atmosphere, 
and  of  so  removing  a  cause  of  danger.  The 
lamp  is  extinguished  because  the  chimney  is 
unable  to  carry  off  the  products  of  combustion 
quickly  enough;  they  spread  out  under  the 
bottom  edge  of  the  chimney,  and  pollute  the 
fresh  current  to  such  an  extent  that  it  becomes  incapable  of 
supporting  the  combustion  of  the  oil. 

The  lamp  will  not  stand  being  jerked  or  inclined,  for  any- 
thing which  will  turn  the  currents  out  of  their  proper  course 
causes  the  bottom  part  of  the  gauze  to  be  filled  with  the  products 
of  combustion  and  puts  the  flame  out.  It  is  evident  that  when 
the  lamp  is  held  in  an  inclined  position,  all  the  foul  gas  will  not 
go  up  the  chimney,  and  that  some  will  become  mixed  with  the 
inward  current;  a  jerk  downwards  checks  the  supply  of  air 
passing  in  through  the  gauze,  and  again  the  lamp  is  extinguished. 
On  the  other  hand,  it  resists  a  horizontal  current  better  than 
the  two  lamps  mentioned  previously.  If  the  lamp  is  struck 


LIGHTING. 


521 


obliquely  by  the  current  an  explosion  may  sometimes  take  place 
inside  it. 

Before  concluding  this  very  short  account  of  the  Mueseler 
lamp,  it  is  important  to  point  out  that  a  mere  diaphragm  with  a 
chimney  does  not  necessarily  constitute  a  lamp  of  the  original 
Belgian  pattern.  The  dimensions  of  the  parts  are  carefully 
prescribed  by  law  in  Belgium,  for  it  has  been  found  that  a 
slight  departure  from  them  may  affect  the  properties  of  the  lamp 
very  materially. 

A  lamp  which  has  come  largely  into  use  of  late  years,  and 
especially  in  this  country  after  the  favourable  report  of  our  Hoyal 
Commission,  is  that  of  M.  Marsaut,  of  Besseges.  to  whom  miners 


FIG.  597. 


FIG.  598. 


are  indebted  for  many  useful  investigations  (Fig.  597).  It  is  of  the 
Clanny  type — that  is  to  say,  it  has  a  glass  cylinder  with  the  air 
entering  above  it,  and  no  chimney ;  but  it  has  the  extra  safety 
afforded  by  a  second  or  even  a  third  gauze,  and  a  bonnet  or  shield 
of  sheet  iron.  These  additions  enable  it  to  resist  currents  of  2000 
feet  per  minute ;  other  advantages  are  an  illuminating  power  of 
about  two-thirds  of  a  standard  candle,  simplicity  and  strength,  for 
the  gauze  is  protected  by  the  shield  from  accidental  blows  of  the 
pick  or  other  sources  of  injury.  The  outer  shield  adds  somewhat 
to  the  weight  of  the  lamp,  but  the  slight  diminution  of  portability 
is  amply  repaid  by  the  increased  security  which  it  affords. 

The  Hepplewhite-Gray  lamp,  with  some  modifications  intro- 
duced by  Ashworth  (Fig.  598),  is  of  a  totally  different  type;  the 
wick  is  fed  with  air  coming  in  below  the  glass,  through  a  ring 


522  ORE  AND  STONE-MINING. 

of  wire  gauze  cZ,  on  the  inside  of  an  annular  chamber.  When 
testing  for  "  gas,"  the  openings  at  the  bottom  of  three  brass 
tubes,  through  which  the  air  passes  into  the  annular  chamber,  are 
closed,  and  the  lamp  draws  its  supply  of  air  from  the  top  of  tubes. 
The  path  taken  by  the  air  is  shown  by  the  arrows ;  b  b  are  the 
holes  by  which  the  products  of  combustion  escape.  The  glass 
is  no  longer  cylindrical,  but  is  made  in  the  form  of  a  truncated 
cone,  with  the  object  of  illuminating  the  roof ;  the  smallness  of 
the  top  of  the  shield  a  conduces  to  the  same  desirable  object.  If 
the  inside  of  the  glass  is  blackened  at  the  back,  the  efficiency 
for  testing  is  decidedly  increased,  as  images  of  the  flame,  such  as 
are  reflected  from  both  sides  of  the  ordinary  glass,  no  longer 
trouble  the  observer.  This  lamp  has  the  further  advantage 
for  testing  that  it  takes  in  its  supply  of  air  from  the  top,  and 
will  therefore  test  a  layer  of  air  close  to  the  roof  which  could 
not  be  examined  by  an  ordinary  lamp,  except  by  tilting  it  so  much 
that  there  would  be  danger  of  its  going  out. 

Locks. — In  order  to  prevent  careless  and  imprudent  men  from 
risking  their  lives  and  those  of  their  comrades  by  opening  their 
lamps,  it  is  necessary  to  lock  them  securely  before  they  are  taken 
into  the  workings.  Various  devices  have  been  proposed  and 
adopted. 

A  little  bolt  screwed  in  by  a  key  like  a  large  watch-key,  through 
the  ring  holding  the  glass  or  the  gauze,  was  thought  at  first  to 
offer  sufficient  guarantee  of  security  ;  but  it  was  soon  found  that 
ingenious  miners  could  pick  a  lock  of  this  kind  without  difficulty, 
and  other  plans  had  to  be  devised  to  baffle  their  skill.  The  most 
common  systems  employed  are  the  lead  rivet,  the  magnetic  bolt, 
and  the  C livelier  fastening. 

The  lead  rivet  is  placed  through  two  holes,  one  in  the  brass  ring 
holding  the  glass  and  the  other  in  the  oil-vessel  j  it  is  then  firmly 
squeezed  with  a  pair  of  nippers,  and  thus  impressed  with  a  mark, 
which  can  be  changed  from  day  to  day  if  necessary.  When  this 
has  been  done,  the  lamp  cannot  be  opened  without  cutting  the 
rivet,  which  would  at  once  be  noticed  when  the  miner  handed  it 
in  at  the  end  of  the  shift.  The  lamp-man  easily  cuts  the 
rivet  before  proceeding  to  clean  the  lamp;  the  pieces  of  lead 
are  collected,  melted  up  again,  and  once  more  cast  into  rivets.  The 
cost  of  this  very  effective  method  of  locking  is  but  slight. 

Several  inventors  have  resorted  to  magnetism  in  order  to 
obtain  an  unpickable  form  of  lock,  and  Wolf's  fastening  is  one 
of  this  description.  It  consists  of  a  bolt  held  in  its  place  by  a 
spring,  which  can  only  be  drawn  back  when  the  lamp  is  placed 
against  a  very  powerful  magnet.  This  form  of  lock  is  largely 
used. 

Cuvelier's  ingenious  fastening,  \vhich  gives  great  satisfaction  at 
some  French  collieries,  may  be  described  as  a  vertical  bolt  which 
keeps  the  lamp  locked  until  it  is  set  free  by  hydraulic  pressure. 


LIGHTING. 


523 


FIG.  599. 


The  two  ends  of  a  piece  of  metal  tube,  bent  into  the  form  of  a 
circle,  come  close  together  under  the  bolt,  whilst  on  the  opposite 
side  there  is  a  projecting  tube  with  a  very  small  hole.  If  hydraulic 
pressure  is  exerted  on  the  inside  of  the  tube  by  means  of  an 
accumulator  acting  through  the  little  hole,  the  two  arms  tend  to 
straighten  out,  and  the  ends  move  a  little  away  from  one  another  ; 
in  so  doing  they  allow  the  bolt  to  fall  from  its  own  weight  and  the 
pressure  of  a  spiral  spring.  The  operation  of  opening  is  very 
quickly  performed,  and  the  hole  in  the  projecting  tube  is  so  small 
— only  i  to  i  of  a  millimetre  in  diameter — that  the  quantity  of 
water  used  is  insignificant.  The  hole  is  on  the  under  side  of  the 
tube  and  has  not  been  found  to  become  choked  up  by  dirt,  as 
might  have  been  expected. 

Gas. — Gas  is  employed  for  lighting  pit-bottoms,  hanging-on 
places,  or  sidings,  where  there  is  a  large  amount  of  traffic. 

Electric  Light. — Up  to  the  present  time,  owing  to  its  want  of 
portability,  the  electric  light  has  not  displaced  candles  and  ordinary 
lamps  in  the  work  of  "getting"  minerals,  save 
in  a  few  special  cases.  It  is  true  that  various 
small  portable  incandescent  lamps  have  been  in- 
vented and  tried,  but  until  lately  they  have  failed 
to  satisfy  all  the  conditions  which  are  necessary 
for  commercial  success. 

More  promising  than  its  predecessors  is  the 
Sussmann  lamp,  which  is  now  coming  into  the 
market.  A  (Fig.  599)  is  a  steel  case  enclosing  a 
dry  storage  battery ;  B  is  an  outer  protecting  cylin- 
der of  glass,  held  between  four  upright  rods,  C ; 
1)  is  the  vacuum  bulb  with  the  filament  which 
becomes  incandescent  ;  E  and  F  are  conical 
whitened  reflectors  destined  to  make  the  best 
possible  use  of  the  light.  The  back  half  of  the 
glass  cylinder  is  whitened  for  a  similar  reason. 

The  lamp  is  2f  inches  square  at  the  base  and 
8  inches  high  ;  it  weighs  3  Ibs.  10  oz.  (1*64  kil.). 
One  pattern  is  said  to  give  a  light  of  one  candle- 
power  for  fourteen  or  fifteen  hours,  and  another 
three  candle-power  for  nine  and  a  half  hours. 
The  advantage  of  this  lamp  over  those  previously 
brought  forward  is  the  absence  of  any  liquid.  The  interior  of 
the  battery  is  solid,  and  consequently  the  lamp  can  be  held  or 
laid  in  any  position.  The  company  owning  the  patents  is  ready 
to  make  contracts  with  mine-owners  to  supply  lamps,  charge 
them  daily,  and  keep  them  in  repair  for  4cZ.  per  lamp  per  week, 
or  about  what  oil  alone  is  costing  at  the  present  time. 

As  regards  its  safety,  it  is  stated,  as  the  result  of  numerous 
experiments,  that  the  smallness  of  the  filament  prevents  any 
chance  of  its  igniting  explosive  mixtures,  in  the  event  of  both  the 


524  ORE  AND  STONE-MINING. 

outer  cylinder  and  the  bulb  being  broken.  Like  all  other  electric 
lamps,  it  has  the  defect  of  affording  no  indication  of  fire-damp  or 
carbonic  acid. 

Where  a  fixed  light  can  be  used — in  other  words,  where  the 
nature  of  the  excavation  to  be  lighted  is  not  rapidly  changing — 
the  electric  light  is  rendering  incalculable  services.  Thus,  in 
sinking  shafts,  a  few  incandescent  lamps  hung  from  an  electric 
cable  enable  the  miner  to  do  his  work  under  unaccustomed  con- 
ditions of  brilliancy.  He  not  only  gets  better  illlumination,  but 
he  is  relieved  from  all  trouble  about  candles  or  lamps,  and  can  set 
about  his  work  as  a  navvy  would  at  the  surface.  This  means  a 
saving  of  time  which  is  often  well  worth  paying  for.  While 
blasting  is  going  on,  the  lamps  are  drawn  up  out  of  the  way  of 
stones  which  might  be  hurled  up  and  break  the  glasses. 

Fixed  glow  lamps  form  a  convenient  and  desirable  means  of 
lighting  up  pit-bottoms,  on-setting  places,  levels  and  sidings  where 
the  trafiic  is  large,  and  ladder-ways  and  man-engines  which  are 
much  frequented. 

When  the  area  to  be  illuminated  is  large,  an  arc-lamp  may  be 
employed  with  advantage.  Among  the  first  successful  applications 
of  electric  lighting  to  underground  excavations  may  be  mentioned 
that  of  M.  Blavier  at  the  Angers  slate  quarries.*  In  the  year 
1879  he  fixed  two  Serrin  lamps  in  one  of  the  large  underground 
chambers  with  an  area  of  2400  square  yards,  and  he  found  that 
they  gave  light  enough  for  all  the  men  at  work.  The  total  cost, 
reckoning  everything — viz.,  coal,  carbons,  repairs,  labour,  deprecia- 
tion of  plant,  and  interest  on  capital — was  50  francs  a  day;  the 
gas  formerly  in  use  cost  54  francs  a  day  and  gave  much  less  light. 
The  large  chambers  in  the  salt-mine  of  Maros-Ujvar  in  Hungary  t 
have  been  lighted  up  by  electricity  since  1880.  The  cost  is  some- 
what greater  than  that  of  the  tallow,  oil,  or  petroleum  formerly 
in  use  ;  but,  per  contra,  the  illumination  is  better,  the  men  can  do 
more  work  and  are  more  easily  supervised,  whilst  the  air  of  the 
mine  is  not  deteriorated  by  the  products  of  combustion  of  the 
lamps.  Slanic  salt-mine  in  Roumania  has  been  lit  with  the 
electric  light  in  a  similar  manner  since  1883. 

In  a  previous  chapter  I  described  the  working  of  the  thick  bed 
of  lead-bearing  sandstone  at  Mechernich  by  large  underground 
chambers,  which  eventually  are  allowed  to  collapse.  Of  late  years 
arc  lights  have  been  largely  used  for  illumination,  although  the 
number  of  men  in  one  chamber  is  never  more  than  six  and  often 
not  more  than  two.  The  great  advantage  derived  from  the  use 
of  the  powerful  light  has  been  the  possibility  of  removing  with 
safety  thousands  of  tons  of  ore,  which  otherwise  would  have  been 
left  undergound  for  fear  of  accidents  in  taking  it  down. 

*  Blavier,  "  L'Eclairage  electrique  aux  Ardoisieres  d'Angers,"  Annales 
des  Mines,  ser.  7,  vol.  xvii.,  1880,  p.  5. 

t  Oest.  Zeitschr.  B.  u.  H.  W.,  1882,  p.  296. 


LIGHTING.  525 

It  is  proposed  to  use  arc  lights  with  reflectors,  similar  to  the 
naval  search  lights,  for  examining  the  roofs  and  sides  of  the  large 
underground  chambers  in  the  Welsh  slate  mines. 

Arc  lights  stand  in  good  stead  when  work  has  to  be  done  at 
night  above  ground.  Thus,  at  Rio  Tinto,  the  great  open-cast 
is  lit  up  by  two  arc  lights,  one  at  each  end  of  the  major  axis  of 
the  elliptical  pit.  In  the  same  way  two  arc  lights  of  2000  candle 
power  are  used  for  night-work  in  washing  down  auriferous  gravel 
at  the  works  of  the  Osceola  Company  in  Nevada.*  As  the  use  of 
electricity  spreads  for  the  purpose  of  transmitting  power,  we  may 
naturally  expect  further  development  of  the  lighting  of  parts  of 
mines  from  the  same  source. 

*  Eny.  Min.  Jour.,  vol.  li.,  1891,  p.  630. 


(     5*6     ) 


CHAPTER   XII. 

DESCENT  AND  ASCENT. 

Steps  and  slides — Ladders — Bucket  or  cage — Man-engine,  single  and 

double. 

AT  first  sight  this  subject  might  seem  scarcely  to  deserve  a  separate 
chapter  ;  but  if  one  considers  the  time  occupied  by  the  miner  in 
going  to  and  from  his  work,  and  recollects  that  his  hours  are 
reckoned  "  from  bank  to  bank" — i.e.,  from  the  moment  he  leaves 
the  surface  till  he  reaches  it  again — and  if  one  further  dwells  upon 
the  terrible  waste  of  energy  involved  by  climbing  up  and  down  deep 
shafts  by  ladders,  it  will  be  admitted  that  the  question  of  descent 
and  ascent  requires  to  be  discussed. 

Where  mines  are  worked  by  adit  levels,  the  men  naturally  walk 
in  along  the  ordinary  roadways.  Such  mines,  however,  are 
exceptional,  and  the  workmen  generally  have  to  climb  down  and 
up  by  ladders,  or  are  lowered  and  raised  by  the  winding 
machinery.  The  means  of  access  to  and  from  the  workings  may 
be  classified  as  follows  : 

1.  Steps  and  slides. 

2.  Ladders. 

3.  Bucket  or  cage. 

4.  Man-engine. 

Steps  and  Slides. — If  the  dip  of  a  seam  or  vein  is  small, 
an  inclined  pathway,  leading  down  through  the  old  workings, 
forms  a  safe  and  pleasant  travelling  road  into  the  mine,  and  it 
has  the  further  advantage  that  the  ponies  or  horses  can  be 
brought  out  at  the  end  of  each  shift. 

When  the  inclination  reaches  20°  it  is  well  to  have  regular 
steps,  instead  of  making  the  men  scramble  down  an  irregular 
path ;  it  is  true  that  the  miner,  accustomed  to  the  road,  does  not 
lose  so  much  time  as  a  stranger  in  picking  his  way  along  a  rough 
or  slippery  track,  but  still  a  bad  path  causes  a  little  unnecessary 
delay  which  is  best  avoided.  Steps  are  much  less  fatiguing  than 
ladders  placed  so  flat  that  part  of  the  weight  of  the  body  has  to 
rest  upon  the  arms. 

Steps  may  be  cut  in  the  rock  itself,  if  it  is  hard  enough,  and  if 
not,  wooden  or  stone  stairs  can  be  put  in,  with  a  handrail.  When 
the  dip  is  too  high  for  making  the  stairs  straight,  they  may  be 


DESCENT  AND  ASCENT.  527 

arranged  in  a  zigzag  line,  provided  that  the  excavation  affords 
sufficient  space.  The  height  of  the  steps  should  not  exceed 
8  inches,  so  as  to  avoid  a  fatiguing  lift  of  the  foot. 

In  parts  of  the  Sicilian  sulphur-mines,*  where  the  dip  does  not 
exceed  30°  to  35°,  the  steps  are  from  8  to  10  inches  high  and  12 
to  14  inches  broad,  and  occupy  the  whole  width  of  the  travelling 
road ;  if  the  dip  is  from  40°  to  50°,  two  sets  of  steps  are  made,  so 
that  the  level  of  the  tread  on  one  side  corresponds  with  the  middle 
of  the  height  on  the  other.  This  system  is  known  as  that  of  the 
scaloni  rotti,  and  greatly  facilitates  the  ascent  up  such  steep 
roads. 

In  some  of  the  Austrian  salt-mines  the  men  descend  by  wooden 
slides  inclined  at  angles  varying  from  30°  to  50°,  flattening  at  the 
bottom  so  as  to  reduce  the  velocity  gradually ;  the  miner  can 
increase  his  speed  by  leaning  forwards  or  lesse'n  it  by  leaning 
back.  The  ascent  is  by  steps. 

Ladders. — Ladders  are  very  largely  used  in  ore-mines  all  over 
the  world,  but  they  vary  a  good  deal  in  different  countries.  In 
Mexico  and  in  Chili,  the  common  ladder  is  merely  a  pole  with 
notches  at  the  sides  for  receiving  the  feet.  These  ladders, 
especially  when  worn,  are  better  fitted  for  barefooted  or  sandaled 
miners  than  for  those  wearing  a  heavy  and  unyielding  boot. 

The  so-called  "  centipede  ladder,"  met  with  in  out-of-the-way 
parts  of  Australia,  and  even  sometimes  seen  in  Europe,  is  very 
properly  condemned  by  the  inspectors  of  mines  in  Queensland.f 
It  is  made  of  a  single  pole,  often  a  sapling  with  the  branches  cut 
off,  with  auger  holes  through  which  wooden  pegs  are  inserted  at 
regular  intervals.  The  projecting  pegs  form  the  rungs  of  the 
ladder.  If  such  a  ladder  is  new,  with  the  pegs  set  evenly  and 
firmly,  and  placed  at  a  proper  angle,  it  will  serve  for  shallow 
depths ;  but  ladders  of  this  description  are  usually  put  in  by  men 
who  are  not  good  at  carpentry,  they  are  hung  vertically,  the  pegs 
are  uneven  originally  or  are  allowed  to  get  rotten,  and  the  suc- 
cessive ladders  are  not  securely  joined ;  the  task  of  climbing  then 
becomes  a  dangerous  one. 

The  ordinary  ladder  consists  of  two  sides  and  a  series  of  rungs 
(staves,  Cornwall).  The  principal  points  that  have  to  be  considered 
are  the  material,  the  size,  and  the  mode  of  fixing. 

In  this  country  the  mine  ladder  is  most  commonly  made  with 
wooden  sides  and  iron  rungs.  The  sides  are  easily  formed  by 
putting  a  sawcut  through  a  plank  as  supplied  by  the  timber- 
merchant.  2  inches  thick  by  8  inches  wide,  giving  two  pieces  4  by  2 
inches ;  pitch-pine  is  largely  used  on  account  of  its  durability. 
The  two  sides  are  fastened  together  temporarily,  and  auger  holes 
bored  through  them  both,  so  that  they  match  exactly.  The  rungs 

*  Parodi,  Sutt*  Estrazione  dello  Solfo  in  Sirilia.    Florence,  1873,  p.  24. 
t  Ann.  Bep.  Dep.  Mines,   Queensland,  for  the  Year  i8$9,  p.  122;   1890, 
p.  130. 


528  ORE  AND  STONE-MINING. 

are  made  of  pieces  of  round  iron,  f  to  J  inches  in  diameter.  It  is 
true  that  one  may  see  §  inch  iron  employed  for  the  rungs ;  but, 
leaving  aside  the  question  of  safety,  this  is  false  economy.  The 
thin  rung  wears  quickly,  if  there  is  much  traffic,  and  soon  has  to 
be  replaced,  entailing  an  expense  which  would  have  repaid  the 
extra  cost  of  the  thicker  iron  in  the  first  instance. 

On  the  Continent  wooden  rungs  are  common,  and  oak  is 
preferred  on  account  of  its  durability  ;  the  wooden  stave  is  often 
made  flat,  instead  of  round,  so  that  it  may  last  longer,  and  iron 
sides  may  be  seen  where  dry  rot  is  very  bad.  A  ladder  made 
entirely  of  wood  is  lighter  than  one  with  iron  staves,  and 
this  is  an  advantage  if  it  has  to  be  moved  about  much.  In  places 
where  an  ordinary  ladder  would  be  knocked  to  pieces  by  blast- 
ing, such  as  the  bottom  of  a  shaft  in  course  of  sinking,  a  short 
length  of  chain  ladder  is  put  in  ;  the  sides  are  made  of  pieces 
of  chain,  and  iron  rungs  are  attached  at  suitable  intervals. 
Wire  rope  is  also  used  for  the  sides  of  ladders,  and  Rochebeau 
uses  steel  tube  for  the  rungs.  He  supplies  the  ladders  of  this 
description,  which  can  be  rolled  up  into  a  coil  and  kept  in  readi- 
ness in  case  of  an  emergency. 

A  very  important  point  is  the  distance  between  the  rungs  :  it 
should  be  chosen  so  as  not  to  cause  too  great  a  lift  of  the  foot  at  each 
step,  whilst  at  the  same  time  the  number  of  steps  must  not  be 
increased  out  of  reason.  Experience  shows  that  a  distance  of  10 
inches  from  centre  to  centre  is  very  suitable ;  ladders  with  a  step 
of  1 1  inches  or  1 2  inches  are  far  more  fatiguing  to  climb.  The 
two  end  rungs  often  have  collars,  and,  like  them,  the  middle  rung 
is  screwed  at  the  ends  for  nuts ;  these  add  to  the  general  strength 
of  the  ladder;  the  sides  are  thus  kept  permanently  about  n 
inches  apart.  If  not  secured  in  some  fashion  the  ends  may  come 
together  a  little  and  the  middle  bulge  out.  It  is  advisable  to  have 
a  uniform  pattern  for  all  the  ladders  in  a  mine,  such  as  14  feet, 
for  instance,  and  when  an  old  ladder  has  tobe  replaced,  a  suit- 
able new  one  is  ready  in  stock,  without  any  delay  for  taking 
measurements  or  making  it.  Two  such  ladders  joined  together 
form  a  very  convenient  length  for  a  "  footway  "  in  a  shaft ;  they 
make  a  ladder  28  feet  long,  and  allowing  4  feet  to  project  above 
the  platform,  for  safety  and  comfort  in  getting  on  and  off,  there 
remains  a  length  of  24  feet  for  actual  climbing  between  the  plat- 
forms or  sollars.  The  two  ladders  can  be  fastened  together  by  an 
iron  strapping-plate  on  each  side,  held  in  position  by  the  nuts  of 
the  two  terminal  rungs.  Where  the  ladders  have  plain  rungs  at 
the  ends  a  strong  wooden  cleat  nailed  on  to  both  ladders  makes 
the  connection.  In  making  the  joint  between  two  ladders,  care 
should  be  taken  to  maintain  the  proper  distance  between  the 
staves  and  the  regular  inclination ;  for  when  once  a  man  has  got 
into  the  rhythm,  so  to  say,  of  climbing,  he  is  liable  to  miss  his 
step  and  fall  if  a  rung  fails  to  come  just  where  he  expects  it. 


DESCENT  AND  ASCENT. 


529 


FIG.  600. 


Fig.  600  represents  a  ladder  *  made  entirely  of  iron,  such  as  is 
largely  used  in  mines  in  the  north  of  France.  The  sides  are  of  flat 
iron,  7  x  70  mm.  (about  \  x  2\  ins.)  and  the  rungs  are  of  round 
iron,  22  mm.  (f  inch)  in  diameter;  they  are  252  mm.  (9-9  inches) 
from  centre  to  centre.  Three  of  the  rungs  are  bolts  with  nuts, 
and  the  others  are  riveted ;  the  manner  of  joining  two  ladders 
by  a  cotter  bolt  with  a  square  end  is  evident 
from  Fig.  60 1.  The  iron  may  be  galvanised 
to  prevent  rusting.  Ladders  of  this  descrip- 
tion weigh  10  kil.  per  metre  (20  Ibs.)  per 
yard. 

Platforms  (sollars,  Cornwall)  should  be  fixed 
at  short  intervals;  though  our  British  law 
allows  them  to  be  placed  60  feet  apart,  the 
distance  can  be  reduced  with  great  advantage 

FIG.  601. 


-ire™.. 

295-M 


IZ-I6.NS 
-30»MU 


to  1 8,  20,  or  24  feet  in  perpendicular  or 
highly  inclined  shafts.  A  much  shorter 
interval  would  mean  too  many  changes,  and 
a  longer  one  would  render  falls  more  danger- 
ous, besides  curtailing  the  number  of  enforced 
short  rests,  which  are  a  relief  in  climbing  up 
from  great  depths.  One  side  of  the  ladder 
may  be  fastened  to  timber  in  the  shaft 
by  strong  staples ;  and  if  not,  it  should  be 
kept  rigid  by  stays,  so  as  to  prevent  any 
swaying. 

Lastly  comes  the  question  of  the  angle  at  which  the  ladder 
should  be  inclined.  The  mine-owner  should  spare  no  pains  to 
render  the  "  travelling "  as  safe  and  as  easy  as  possible,  and 
should  recollect  that  the  miner  climbs  with  the  least  amount  of 
fatigue,  when  the  greater  part  of  the  work  of  raising  the  body  is 
thrown  upon  the  muscles  of  the  legs  and  not  upon  those  of  the 

*  One  of  the  patterns  supplied  by  Komain  Sartiaux,  of  Henin-Lietard, 
Pas-de-Calais. 

2  L 


530 


ORE  AND  STONE-MINING. 


arms;  the  part  played  by  the  arms  should  be  keeping  the 
body  in  a  proper  position  and  preventing  falls.  It  may  here  be 
noted  that  the  miner  does  not  climb  a  ladder  like  a  bricklayer  or 
a  house-painter.  The  latter  place  their  hands  upon  the  sides  of  the 
ladder ;  the  miner  grasps  the  rungs,  and  even  if  his  foot  slips,  or 
if  a  faulty  rung  gives  way  under  him,  he  has  a  chance  of  saving 
himself.  In  climbing  down  he  frequently  misses  every  alternate 
stave  with  his  hands,  or,  in  other  words,  he  makes  two  steps  with 
his  feet  for  one  grasp  with  the  hand. 

The  most  convenient  angle  for  ladders  is  about  20°  from 
the  vertical ;  if  they  are  much  natter  than  this,  the  arms 
have  to  be  used  in  order  to  prevent  the  body  from  falling 
forwards ;  if  they  are  steeper,  the  arms  have  to  lift  part  of  the 
weight  of  the  body.  In  either  case  there  is  fatigue  for  the  arms, 
and  in  the  latter  the  danger  of  falls  is  increased;  these  dis- 
advantages become  very  marked  when  the  ladders  are  placed  in  a 
vertical  or  overhanging  position.  Ladders  so  fixed  are  prohibited 
by  law  in  this  country,  for  it  is  not  only  the  life  of  the  man  who 
falls  which  is  endangered,  but  he  may  sweep  off  several  men 
beneath  him.  Unfortunately,  our  present  law  does  not  go  quite  far 
enough  ;  it  forbids  a  vertical  ladder,  but  permits  a  ladder  inclined 
at  an  angle  of  i°  or  2°  from  the  vertical,  provided  the  shaft  is  not 
large  enough  to  admit  of  any  better  arrangement.  In  other  words, 
it  does  not  compel  the  mine-owner  to  sink 
a  shaft  large  enough  for  a  proper  ladder- 
road.  The  Belgian  law,*  enacted  twenty- 
one  years  before  ours,  is  more  wisely 
worded  ;  it  decrees  that  no  ladder  shall  be 
inclined  at  an  angle  of  less  than  10°  from 
the  vertical. 

Furthermore,  of  the  two  arrangements 
shown  in  Fig.  602,  A  is  better  than  B, 
because  it  not  only  affords  a  greater  in- 
clination for  the  ladders,  but  also  renders 
it  less  likely  that  a  man  will  drop  through 
the  opening  (manhole)  in  the  platform 
(sollar)  if  he  loses  his  hold  and  falls.  In 
planning  the  regular  permanent  ladder-road 
for  the  miners,  it  is  well  to  avoid  shafts 
in  which  other  operations,  such  as  winding 
or  pumping,  are  going  on.  By  law,  in  this  country,  the  ladder 
compartment  has  to  be  partitioned  off  from  the  winding  compart- 
ment ;  a  better  plan,  if  possible,  is  to  provide  an  entirely  separate 
shaft  for  a  footway.  In  vein  mines,  a  number  of  the  winzes  can 
conveniently  be  set  apart  for  "  travelling  "  purposes.  Occasionally 
the  ladderway  is  made  double  in  the  upper  part  of  the  mine,  so 


FIG.  602. 


*  ArrSte  royal  du  Janvier  1851,  Article  2. 


DESCENT  AND  ASCENT.  531 

as  to  prevent  loss  of  time  at  the  change  of  the  shifts,  when  an 
ascending  stream  of  men  meets  a  similar  descending  stream. 

Some  of  the  matters  just  mentioned  may  seem  trifling,  but, 
leaving  aside  the  question  of  safety,  the  economy  derived  from 
fixing  the  ladders  at  the  best  possible  inclination  is  by  no  means 
small.  To  make  this  apparent,  we  must  recollect  the  depths  to 
and  from  which  men  have  to  climb — viz.,  300,  400,  and  even 
500  yards  or  more.  It  is,  therefore,  important  to  save  every 
unnecessary  expenditure  of  energy,  which,  though  trifling  for  one 
ladder,  becomes  considerable  if  very  frequently  repeated.  When 
a  mine  has  reached  a  depth  of  100  yards,  and  a  fortiori  when  it 
has  exceeded  it,  mechanical  appliances  should  certainly  be  intro- 
duced for  raising  and  lowering  the  men,  because  time  and  strength 
are  wasted  by  climbing  ;  besides  which,  medical  men  are  agreed 
that  excessive  ladder-climbing  is  injurious  to  the  health  of  the 
miner.  Therefore  upon  hygienic  and  upon  financial  grounds,  one 
of  the  first  thoughts  in  working  a  mine  should  be  the  conveyance 
of  the  men  down  and  up  the  shaft  with  the  least  possible  fatigue, 
by  means  of  machinery. 

Buckets  and  Cages. — This  method  of  going  down  and  com- 
ing up  from  mines  recommends  itself  by  its  simplicity,  and  when 
•carried  out  with  modern  appliances  it  is  remarkably  safe. 

If  the  machinery  is  being  worked  by  hand,  the  miner  usually 
stands  with  one  foot  in  the  kibble  and  uses  the  other  to  guide 
himself,  while  he  holds  the  rope  in  his  hands ;  this  guiding  is 
specially  necessary  when  going  down  an  inclined  winze  with 
Tough  and  rugged  sides.  Some  men  prefer  to  have  one  foot  in 
a  loop  at  the  end  of  the  rope,  whilst  others  like  a  special  stirrup. 

At  the  ozokerite  mines  of  Boryslaw,  and  also  in  sinking  oil- 
wells  in  Burma,  special  precautions  are  taken  in  case  the  men 
should  become  unconscious  from  breathing  an  atmosphere  highly 
charged  with  noxious  gases.  In  every  case  the  man  is  secured 
by  a  second  rope,  so  that  he  can  be  drawn  up  even  if  he  falls 
from  the  bucket.  The  Boryslaw  safety-gear  is  a  strong  leathern 
waist-belt  to  which  is  attached  a  broad  strap  divided  into  two  at 
each  end.  One  thong  passes  over  each  shoulder  and  is  buckled 
to  the  belt,  and  one  under  each  leg  is  attached  in  a  similar 
manner.  An  iron  ring  between  the  shoulders  completes  the  gear. 
It  serves  for  attaching  the  second  rope,  or  life-line,  coiled  upon  a 
separate  windlass,  and  paid  out  as  fast  as  the  main  rope  with  the 
bucket  in  which  the  man  stands  with  one  leg.  Many  of  the 
shafts  worked  in  this  way  are  more  than  150  yards  deep,  and  one 
has  attained  a  depth  of  262  yards  (240  metres). 

Guides  are  compulsory  in  this  country  after  a  depth  of  50  yards 
is  exceeded,  unless  the  owner  of  the  mine  has  obtained  an  exemp- 
tion from  the  inspector  of  the  district.  I  explained  in  the  chapter 
upon  winding  how  they  can  be  applied  to  the  kibble  or  bucket 
even  in  a  sinking  shaft ;  but  the  usual  method  of  ascent  and 


532  ORE  AND  STONE-MINING. 

descent  is  by  the  cage,  or  some  form  of  guided  box.  Little  need  be 
said  about  the  process  of  lowering  and  raising,  for  it  is  practically 
the  same  as  winding  mineral.  Rules  are  made  defining  the 
number  of  men  allowed  to  ride  at  one  time,  and  generally  there 
is  a  bar  near  the  top  of  the  cage  which  the  men  can  hold,  in  case 
there  should  be  a  little  jerk.  In  some  countries  it  is  necessary 
that  the  cage  should  be  so  enclosed  that  there  is  no  possibility  of 
a  man  falling  out  during  his  rapid  ride.  As  sending  the  men 
down  and  up  in  this  fashion  interferes  with  the  winding  of 
minerals,  access  to  the  cage  should  be  easy ;  even  stooping  causes 
a  little  loss  of  time,  and  the  despatch  of  the  men  into  the  mine 
will  be  expedited  if  the  cage  is  high  enough  for  them  to  walk 
in  upright  without  any  thought  for  their  heads.  If  the  space  is 
too  low  for  standing  up  conveniently,  the  men  may  be  made  to 
crouch  down  in  mine-waggons,  which  are  pushed  on  to  the  cage  as- 
if  they  contained  mineral. 

The  extent  of  the  interference  with  the  regular  winding  opera- 
tions will  be  best  understood  by  examples.  The  Government 
regulations  at  Mansfeld*  do  not  allow  a  greater  speed  than  328 
yards  per  minute  (5  metres  per  second)  when  men  are  being 
wound.  At  Ernst  I.  shaft,  which  is  411  yards  (376  metres)  deep, 
it  was  reckoned,  a  few  years  ago,  that  seven  hours  out  of  the 
twenty-four  were  occupied  with  the  descent  and  ascent  of  1069 
persons,  thus : 

Persons. 

Morning  from    4.30  A.M.  to    6. 30  A.M.,  2  hours          ...  450 

Afternoon,,      12.30  P.M.  „     3.45  P.M.,  3$     „  ...  415 

Evening     „       9.15  P.M.  „  n.o    P.M.,  if    ,,  204 

Total 7       „  ...  1069 

At  Ernst  III.  shaft,  which  is  273  yards  (250  m.)  deep,  the 
figures  were  as  follows : 

Persons. 

Morning  from     5.0  A.M.  to    6. 15  A.M.,  labours          ...  260 

Afternoon,.        1.15  P.M.  ,,     2.30  P.M.,  ij    „  ..  234 

Evening      ,',        9.30  P.M.  „  10.30  P.M.,  i       „  149 

Total 31     „  ...  643 

The  cage  at  the  former  shaft  took  seven  men  at  a  time,  and 
that  of  the  latter,  sixteen  men,  as  it  was  double-decked. 

With  the  object  of  relieving  the  ordinary  winding-plant  from 
this  task  in  one  part  of  the  district,  a  new  shaft  was  sunk  solely 
for  raising  and  lowering  the  men. 

The  British  law  demands  that,  in  addition  to  the  guides  already 
mentioned,  there  should  be  a  cover  overhead,  so  as  to  protect  the 
men  from  things  accidentally  falling  down  the  shaft.  The  use  of 

*  Der  Kupfersehieferbergbau  und  der  Jfiittenbetrieb  zur  Verarbeitung  der 
gewonnenen  Minern  in  den  beiden  Mans/elder  Kreisen  der  Preuss.  Provinz 
Saclisen.  Halle  an  der  Saale,  1889,  p.  72. 


DESCENT  AND  ASCENT.  533 

.a  single-linked  chain  is  forbidden,  except  for  the  short  coupling 
piece  connecting  the  cage  to  the  rope.  There  must  be  flanges  to 
prevent  the  rope  from  slipping  off  the  drum ;  the  winding 
machine  has  to  be  provided  with  an  adequate  brake  and  a  proper 
indicator ;  and,  lastly,  there  must  be  means  of  signalling  up  and 
down  from  every  landing-place  in  the  shaft.  In  some  countries 
safety  catches  are  compulsory. 

An  ingenious  and  useful  method  of  signalling  is  that  of  Mr. 
Armstrong,  who  inserts  an  electrically  insulated  wire  into  the  centre 
of  the  winding  rope  for  the  purpose  of  communicating  from  the  cage 
itself  to  the  engineman,  no  matter  whether  the  cage  is  in  motion 
or  not.  The  electric  wire  is  brought  into  contact  with  an  insulated 
metal  ring  placed  upon  the  crank  shaft  of  the  engine,  and  a 
copper  lever  pressing  upon  this  ring  places  the  wire  in  communi- 
cation with  a  small  battery.  The  wire  rope  itself  serves  as  a 
return.  The  circuit  can  be  completed  by  pushing  a  button  inside 
the  cage,  or  another  placed  upon  the  roof,  and  the  ringing  of  a 
bell  at  the  surface  gives  the  necessary  signals  to  the  engineman. 
This  rope,  which  is  made  by  Messrs.  Haggie  &  Co.,  of  Sunder- 
land,  is  being  used  with  success  at  collieries  in  the  north  of 
England,  and  at  one  of  them  a  separate  shaft  is  set  apart  for  the 
men,  so  as  not  to  interfere  at  all  with  the  winding  of  coal ;  the 
cage  carries  twenty  men  at  once,  and  is  always  in  charge  of  a  con- 
ductor, whose  duties  resemble  those  of  the  attendant  at  an  hotel 
lift  or  elevator.  By  merely  pressing  a  button  he  signals  direct  to 
the  engineman  to  start  or  to  stop  as  required. 

At  mines  under  the  Coal  Mines  Act  in  this  country,  the  rate 
of  winding  men  must  not  exceed  three  miles  an  hour  after  the 
cage  has  reached  a  point  in  the  shaft  which  is  fixed  by  Special 
Rules.  However,  this  regulation  applies  only  in  cases  where  the 
hoisting  apparatus  is  not  provided  with  some  automatic  contriv- 
ance to  prevent  overwinding.  In  Germany  a  speed  indicator 
has  to  be  applied  when  men  are  being  raised  or  lowered ;  among 
instruments  of  this  class  may  be  mentioned  the  tachometer  of 
Messrs.  Schaffer  and  Budenberg,  which  indicates  the  rate  of 
winding  by  a  pointer  on  a  dial  in  full  view  of  the  engineman. 

Winding  by  the  cage  is  not  confined  to  perpendicular  shafts. 
At  Carn  Brea  Mine  in  Cornwall  a  two-decked  cage,  holding  six- 
teen persons,  runs  in  a  shaft  which  is  perpendicular  for  the 
first  120  fathoms  and  then  follows  the  changing  dip  of  the  lode 
for  170  fathoms  more.  The  inclination  varies  from  about  10°  to 
30°  from  the  vertical.  In  a  shaft  of  this  kind  it  is  impossible  to 
wind  with  safety  at  speeds  which  are  common  at  collieries  ; 
nevertheless  the  cage  does  very  useful  work,  and  as  the  rope  is 
renewed  every  four  months,  there  is  little  chance  of  a  breakage. 
The  cage  at  Junge  hohe  Birke*  Mine,  near  Freiberg,  consists  of 

*  Freibergs  Berg-  und  Huttemcesen,  1893,  p.  156. 


534 


OEE  AND  STONE-MINING. 


FIGS.  603,  604. 
A 


••  ••  .1 


five  small  compartments  one  above  the  other,  each  forming,  as  it 
were,  a  separate  link  of  a  chain ;  the  cage  can  thus  accommodate 
itself  to  bends  in  the  shaft.  Each  compartment  takes  two  men. 

Man-engine. — The  first  man-engine  was  put  up  in  the  Hartz 
in  1833,  and  nine  years  later  a  similar  machine  was  fixed  in 
Tresavean  Mine  in  Cornwall.  Since  that  time  this  useful  means 
of  conveying  men  up  and  down  shafts  has  been  resorted  to  in 
other  mining  districts,  such  as  Belgium,  Westphalia,  and  Saxony. 
Two  kinds  of  man-engine  are  in  use — the  double-rod  and  the 
single-rod  machines. 

The  double-rod,  or  original  man-engine,  consists  of  two 
reciprocating  rods,  like  the  main  rods  of  pumps,  carrying  small 
platforms  upon  which  the  men  stand.  The  stroke 
is  from  4  to  16  feet,  and  the  little  platforms  are 
arranged  so  that  they  are  always  opposite  each 
other  at  the  beginning  and  end  of  each  stroke. 

Figs.  603  and  604  represent  the  rods  in  the  two 
final  positions.     A  man  who  wishes  to  go  down, 
steps  upon  platform  b  (Fig.  603),  the  rod  B  goes 
down  and  A  goes  up,  so  that  b  is  brought  oppo- 
site c  (Fig.  604).      The  man  steps  across  from  b 
to  c,  the  rod  A  makes  a  down  stroke,  and  B  an 
up-stroke.     Platform  c  is  now  opposite  d  (Fig. 
603),  and  the  man  again  steps  across  ; 
and    thus,    by   constantly    stepping       FIG.  605. 
from  the    rod  as    it   completes    its 
down-stroke,  the    man  is  gradually 
conveyed  to  the  bottom  of  the  shaft. 
By  reversing  the  process,  or,  in  other 
words,    by  stepping   off  on    to    the 
opposite  platform  as  soon  as  the  rod  has  completed  its 
up-stroke,  the  man  is  raised  to  the  surface  without  any 
fatigue  beyond  the  very  slight  effort  of  stepping  side- 
ways.    If  each  rod  makes  four  up  and  down  strokes 
of    10  feet  each  per  minute,  the  rate  of  ascent  or 
descent  will  be  80  feet  per  minute. 

The  single-rod  man- engine  has  one  rod  carrying 
steps,   while    fixed    platforms    are    arranged  in  the 
shaft  so  as  to  correspond  exactly  with  them  (Fig.  605). 
If  a  man  wants  to  go  down,  he  steps  on  to  A  when 
the  up-stroke  is  completed ;  the  rod  goes  down  and 
the  step  A  is  brought  opposite  the  fixed  platform  5, 
on  to  which  he  steps  off.     He  then  waits  on  b  until 
the  rod  has  finished  its  up-stroke.      B  is  brought 
opposite  b,  he  steps  on  to  B,  the  rod  goes  down  and  he  is  brought 
opposite  c,  where  he  again  steps  off  and  waits.     By  reversing  the 
operation  he  is  gradually  lifted   up  to  the  top  of  the  shaft.     The- 
single-rod  engine  may  be  used  by  men  going  up  while  others  are- 


DESCENT  AND  ASCENT.  535 

going  down,  provided  that  there  is  sufficient  room  upon  the  fixed 
platforms  (sollars,  Cornwall).  It  is  best  to  have  platforms  right 
and  left,  as  shown  in  the  figure,  and  then  the  ascending  men  step 
off  always  to  the  left,  for  instance,  while  the  descending  men  take 
the  right  hand  sollars.  The  ascending  man  steps  on  to  the  man- 
engine  as  soon  as  the  descending  man  steps  off,  and  so  the  rod 
may  be  always  carrying  men  up  or  down.  The  usual  stroke  in 
Cornwall  is  12  feet,  and  there  are  from  3  to  6  double  strokes 
per  minute.  With  5  strokes  the  men  descend  10  fathoms  a 
minute,  or,  in  other  words,  a  descent  or  ascent  of  300  fathoms 
occupies  half-an-hour.  However,  after  the  first  man  has  reached 
the  bottom,  the  rest  will  be  coming  down  at  the  rate  of  five  a 
minute.  The  reciprocating  motion  is  best  obtained  from  a  crank 
(Fig.  706),  because  in  this  case  the  speed  is  gradually  diminished 
at  the  dead  points,  and  the  danger  of  an  accident  in  stepping  off 
and  on  is  thereby  lessened ;  man-engines,  however,  are  sometimes 
driven  by  direct-acting  engines,  and,  at  Laxey  Mine,  in  the  Isle  of 
Man,  a  water-pressure  engine  furnishes  the  motive  power  for 
one  of  these  machines. 

Man-engine  rods  are  constructed  of  wood  or  iron ;  and  at  St. 
Andreasberg,  in  the  Hartz,  each  rod  was  replaced  by  two  wire 
ropes.  Like  a  pump  rod  the  man-engine  rod  requires  proper 
balance-bobs  and  catches,  and  for  the  safety  of  the  men  a  handle 
is  provided  at  a  convenient  height  above  each  step.  Sloping 
boards  should  be  fixed  under  each  platform,  so  as  to  make  a 
funnel-shaped  passage  guiding  the  man's  head  into  the  proper 
channel,  in  case  he  is  not  standing  upright  when  "riding"  up. 
A  useful  addition  is  a  small  wire  rope  passing  down  from  sollar 
to  sollar,  and  placed  within  easy  reach  of  a  man  when  standing 
on  a  step ;  he  grasps  this  with  one  hand  as  he  steps  off  on  going 
down,  and  steadies  himself  by  it  if  necessary.  When  riding  up, 
he  passes  through  the  sollar  and  sees  where  he  is  going  to  step 
before  he  gets  off,  so  it  is  not  required  on  both  sides  of  the  fixed 
platform.  There  should  be  a  signal  line,  with  means  of  working 
it,  at  every  sollar,  for  enabling  any  miner  to  ring  and  stop  the 
man-engine  in  case  of  an  accident.  It  is  well,  too,  to  have  a 
ladder-road  at  the  side  of  the  man-engine,  in  order  to  afford  a 
means  of  going  up  or  down  in  the  event  of  some  unexpected 
breakdown  of  the  machinery ;  but  the  plan  of  fixing  this  ladder- 
way  between  the  two  rods  of  a  double  engine  is  not  to  be  com- 
mended, for  the  wider  the  space  between  the  rods  the  greater  the 
chance  of  an  accident. 

The  man-engine  has  the  advantage  that  it  can  be  safely  applied 
in  inclined  and  crooked  shafts,  and  it  is  convenient  in  vein-mining 
where  the  men  have  to  work  at  very  many  different  levels. 

The  cost  of  raising  and  lowering  men  by  the  machine  is  not 
great.  At  Dolcoath,  a  tin  mine  in  Cornwall,  more  than  400 
fathoms  deep,  it  was  reckoned  a  few  years  ago  that  \\d.  per  man 


536  OKE  AND  STONE-MINING. 

per  day  covered  all  expenses,  including  interest  upon  the  capital 
expended  and  depreciation  of  plant. 

Judging  by  what  has  taken  place  during  the  last  ten  years,  it 
seems  likely  that  the  man-engine  will  eventually  die  a  natural 
death.  It  has  all  but  disappeared  at  Mansfeld,  being  replaced 
by  the  safer  and  more  convenient  cage,  and  there  seems  little 
probability  of  new  machines  being  erected  in  Cornwall. 


(     537     ) 


CHAPTER  XIII. 
DRESSING. 

I.  Mechanical  processes:  (i)  Washing  in  order  to  separate  clay,  mud  and 
sand — (2)  Hand-picking — (3)  Breaking  up,  subdivision,  or  shaping — 
(4)  Agglomeration  or  consolidation — (5)  Screening  or  sifting.  II.  Pro- 
cesses depending  upon  physical  properties  :  (i)  Motion  in  water — (2) 
Motion  in  air — (3)  Desiccation — (4)  Liquefaction  and  distillation — (5) 
Magnetic  attraction — (6)  Separation  according  to  degree  of  friability. 
III.  Processes  depending  upon  chemical  properties  :  ( i )  Solution,  eva- 
poration, and  crystallisation — (2)  Atmospheric  weathering— (3)  Calci- 
nation— (4)  Cementation  or  precipitation  by  iron — (5)  Amalgamation. 

Examples — Loss  in  dressing — Sampling. 

UNDER  the  convenient  term  of  "dressing"  are  included  the 
processes  by  which  the  miner  prepares  his  mineral  for  sale,  or  by 
which  he  extracts  a  marketable  product  from  it.  These  processes 
are  very  various,  and  cannot  all  be  properly  comprised  under  the 
French  heading  "Preparation  mecanique,"  because,  in  addition  to 
using  mechanical  means,  the  miner  often  invokes  the  aid  of  heat, 
magnetism,  or  chemical  affinity,  in  order  to  separate  the  valuable 
material,  from  the  worthless  rock  with  which  it  is  associated  in 
the  earth.  It  must  also  be  recollected  that  there  is  a  borderland 
between  mining  and  metallurgy,  on  which  both  miner  and  smelter 
may  fairly  claim  a  footing,  because  the  former  does  not  always 
send  away  his  ore  in  the  same  state  of  elaboration.  Some  may  be 
inclined  to  cut  the  knot  by  saying  that  the  business  of  the  miner 
is  at  an  end  when  the  mineral  is  landed  at  the  surface ;  but  in 
actual  practice  this  is  the  exception,  and  the  person  in  charge  of 
the  mine  has  usually  to  superintend  certain  processes  which  are 
carried  on  in  order  to  obtain  a  readily  saleable  article. 

I  propose  in  this  chapter  first  to  describe  the  various  dressing 
processes,  and  then  to  explain  how  they  are  applied  to  the 
most  important  minerals  with  which  the  miner  has  to  deal. 

In  order  to  have  a  clear  idea  of  the  principles  which  guide 
the  miner,  it  is  requisite  that  we  should  classify  the  processes 
which  he  employs;  and  we  may  at  once  make  three  main 
divisions,  according  as  the  process  is  effected  solely  by  mechanical 
means,  or  is  based  upon  the  physical  or  chemical  properties  of  the 
minerals  treated.  This  classification  is  somewhat  arbitrary : 
differences  of  opinion  may  exist,  for  instance,  concerning  solution, 
some  persons  considering  it  as  a  chemical  process,  others,  as  a  mere 


538  ORE  AND  STONE-MINING. 

change  of  state  without  any  chemical  action  ;  again  the  process  by 
which  a  physical  property  is  brought  into  play  is  usually  effected 
with  the  aid  of  mechanical  appliances ;  and  lastly,  chemical  and 
physical  actions  may  both  be  involved  in  the  method  of  treatment. 
It  must,  therefore,  be  understood  that  the  classification  is  estab- 
lished rather  for  the  convenience  of  the  student,  than  with  the 
idea  that  the  subdivisions  of  the  subject  are  strictly  denned  in 
reality.  It  will  be  seen  also  as  we  proceed,  that  many  of  the 
sub-classes  refer  to  exceptional  processes  applicable  only  to  special 
minerals. 

The  following  table  gives  an  outline  of  the  operations  employed 
in  dressing : 

I.  MECHANICAL  PROCESSES. 

1.  Washing  in  order  to  separate  clay,  mud  and  sand. 

2.  Hand-picking. 

3.  Breaking  up,  subdivision,  or  shaping. 

4.  Agglomeration  or  consolidation. 

5.  Screening  or  sifting — i.e.,  classification  according  to  size. 

II.  PROCESSES  DEPENDING  UPON  PHYSICAL  PROPERTIES. 

1.  Motion  in  water. 

2.  Motion  in  air. 

3.  Desiccation. 

4.  Liquefaction  and  distillation. 

5.  Magnetic  attraction. 

6.  Separation  according  to  degree  of  friability. 

III.  PROCESSES  DEPENDING  UPON  CHEMICAL  PROPERTIES. 

1.  Solution,  evaporation  and  crystallisation. 

2.  Atmospheric  weathering. 

3.  Calcination. 

4.  Cementation  or  precipitation  by  iron. 

5.  Amalgamation. 

i.  MECHANICAL  PROCESSES. 

(i)  WASHING. — The  object  of  washing  is  twofold:  removal 
of  earthy  impurities,  and  preliminary  cleansing  previous  to  hand- 
picking,  for  the  valuable  mineral,  as  it  comes  from  the  mine,  is 
often  completely  masked  by  a  coating  of  dirt. 

The  process  is  carried  out  by  hand  or  by  machinery.  The 
simplest  appliances  are  the  pan  and  the  batea,  which  are  specially 
used  in  the  case  of  gold  and  tin.  The  pan  is  a  circular  dish  made 
of  tin-plate  or  stamped  iron  or  steel,  about  15  or  16  inches  in 
diameter  at  the  top  and  10  or  u  at  the  bottom,  with  a  depth  of  3 
or  4  inches.  After  having  been  partly  filled  with  the  mineral  to 
be  washed,  it  is  held  in  a  pool  of  water,  or  a  vat,  in  which  it  can 
be  moved  so  as  to  impart  a  circular  motion  to  its  contents.  By 
suitably  inclining  the  edge,  the  muddy  stream  is  made  to  flow  off, 
more  clean  water  is  taken  on,  and  the  process  is  repeated  until  there 


DRESSING.  539 

remains  nothing  but  well-washed  sand  and  gravel  in  the  bottom.  The 
big  stones  are  taken  out  and  examined,  and  thrown  away  if  worth- 
less ;  large  nuggets,  if  present,  are  now  visible  and  can  be  picked 
out,  whilst  the  small  stones  and  sand  are  again  mixed  with  water 
and  washed,  so  that  the  lighter  particles  flow  over  the  edge  and  the 
heavy  ones  remain  in  the  pan.  By  careful  manipulation  the 
water  is  made  to  run  repeatedly  over  the  residue,  and  separate  the 
various  ingredients  according  to  their  specific  gravities,  as  will  be 
explained  later.  The  pan,  therefore,  acts  not  only  as  a  washer,  but 
also  as  a  concentrator. 

Though  the  main  use  of  the  pan  is  for  prospecting,  it  must  be 
remembered  that  very  large  quantities  of  alluvial  gold  have  been 
extracted  by  its  aid. 

The  batea  fulfils  the  same  purpose  as  the  pan.  It  is  usually 
a  shallow  conical  bowl  made  of  wood,  stamped  sheet  iron, 
hammered  copper,  or  spun  aluminium  or  copper.  Convenient 
dimensions  are:  diameter  18  to  20  inches  and  depth  2.\  to  3 
inches.  In  some  parts  of  India  the  wooden  gold-washing  dish  is 
rectangular.  The  mineral  is  treated  much  in  the  same  way  as  in  the 
pan,  but  the  batea  has  the  great  advantage  of  bringing  all  the 
heaviest  particles  to  a  point,  instead  of  an  edge.  Much  gold  has 
been  obtained  with  this  primitive  appliance,  especially  in  South 
America  and  Central  America,  whilst  in  the  Malay  Peninsula 
it  is  used  for  extracting  tin  ore  from  gravel,  and  in  Brazil 
for  washing  out  diamonds.  In  prospecting  the  batea  is  in- 
valuable. 

If  large  quantities  of  mineral  have  to  be  handled,  it  is  necessary 
to  separate  the  adherent  dirt  in  some  cheaper  fashion.  Occupying 
an  intermediate  position  between  the  hand-bowls  and  the  rotary 
machines  are  simple  washing  pits  of  different  descriptions. 

Some  of  the  lead  ore  of  North  Wales  occurs  in  the  form  of  solid 
lumps  of  galena  enveloped  in  clay.  The  ore  coming  from  the 
mine  is  thrown  into  a  stone-lined  pit  about  18  inches  deep,  partly 
filled  with  water,  in  which  it  is  pushed  backwards  and  forwards 
until  the  galena  is  separated  from  its  clayey  matrix.  This  kind  of 
washing  pit  is  known  as  a  ''jobbing  buddle." 

Phosphatic  nodules  are  cleansed  from  sand  in  a  similar  manner, 
by  being  raked  or  shovelled  backwards  and  forwards  in  long 
wooden  troughs  full  of  water. 

The  Australian  puddling  machine  is  an  example  of  an 
appliance  for  doing  similar  work  by  the  aid  of  a  horse  or  other 
available  power.  It  is  a  circular  pit  in  which  gold-bearing  gravel 
is  stirred  up  with  water  by  knives  attached  to  radial  arms,  which 
are  carried  round  by  a  vertical  axis. 

The  rotary  washing  machine  employed  at  the  diamond  mines 
(Fig.  606)  is  identical  in  principle.  The  object  is  to  free  the 
weathered  "  blue  ground  "  from  the  finest  sand  and  mud  and  leave  a 
clean  gravel  in  which  the  diamonds  shall  be  distinctly  visible.  The 


540 


ORE  AND  STONE-MINING. 


rotary  washer  is  an  annular  iron  pan  A  (Fig.  606)  8  to  15  feet  in 
diameter  and  16  inches  to  2  feet  deep  externally,  whilst  the  inner 
rim,  B,  4  feet  in  diameter,  is  only  6  inches  deep.  In  the  centre 
is  a  revolving  vertical  shaft,  C,  carrying  8  or  10  radial  arms, 
D,  each  provided  with  6  or  7  vertical  blades  which  dip  into  the 
mud  and  gravel,  and  stir  it  up  as  they  revolve.  At  De  Beers 
mine  the  washers  are  usually  14  feet  in  diameter.  The  stuff  is 
fed  in  at  the  outer  circumference  by  a  shoot  coming  from  a 
screen,  and  the  muddy  water  escapes  over  the  low  inner  rim  of 
the  pan.  The  teeth  or  stirring  knives  are  arranged  so  as  to  bring 

FIG.  606. 


SCAUE: 


DECIMETRES  10 


8          a  FE.ET 

2  METRES 


the  heavy  gravel  towards  the  outer  circumference.  As  a  pre- 
caution, the  muddy  water  flowing  out  of  the  washer  is  run  into 
a  similar  machine,  and  is  again  stirred  up  so  as  to  catch  any 
diamonds  which  may  by  chance  have  escaped  in  the  first  operation. 
When  the  pan  has  been  at  work  for  twelve  hours,  a  sliding  door 
is  pulled  out  at  the  bottom,  through  which  the  gravel  falls  into  a 
truck  underneath,  as  it  is  drawn  round  by  scrapers  attached  to 
the  arms. 

Another  form  of  mechanical  washer*  (Fig.  607)  is  a  revolving 
sheet  iron  drum,  made  in  the  form  of  a  truncated  cone  revolving 
upon  a  horizontal  axis,  and  provided  with  internal  stirring  blades. 
The  "  stuff  "  to  be  washed  is  fed  in  at  the  centre  of  the  small  end 

*  Linkenbach,  Die  Aufbereitung  der  Erse,  Berlin,  1887,  plate  II. 


DRESSING. 


54i 


with  a  stream  of  water.  In  Fig.  607,  a  is  the  drum,  b  the  conical 
mouth,  CG  the  arms  which  attach  the  drum  to  the  central  shaft  d ; 
ee  are  teeth,  f  the  shoot  from  a  hopper,  g  a  pipe  bringing  water,  the 
amount  of  which  can  be  regulated  by  a  cock.  The  greater  part  of 
this  particular  drum  is  perforated,  and  it  acts  as  a  sizing  machine 
after  having  done  the  washing ;  m  is  the  driving  pulley,  h  an  iron 
trough  catching  the  discharge  of  the  sieve,  and  i  a  small  trough 
which  takes  the  stones  discarded  by  the  sieve. 

This  machine  is  intended  for  washing  small  stuff  ("  smalls  ")• 
previous  to  picking.  The  washing  of  the  larger  lumps  is  often 
effected  by  turning  a  stream  of  water  upon  them  over  a  coarse 
iron  grating. 

FIG.  607. 


(2)  HAND-PICKING-. — No  process  is  simpler  in  principle,  it  is 
merely  the  separation  by  hand  into  classes  of  varying  quality  and 
richness ;  the  difficulty  in  practice  is  to  know  how  far  it  should 
be  carried,  before  the  mineral  is  treated  by  machinery. 

In  many  cases  hand-picking  may  begin  underground,  and 
where  worthless  rock  can  be  so  separated  without  difficulty, 
it  should  be  removed  with  care,  so  as  to  avoid  useless  ex- 
penditure for  tramming,  hoisting  and  dressing.  If  a  mineral 
is  specially  valuable,  it  is  often  worth  while  picking  it  out  and 
sending  it  up  by  itself,  with  a  view  to  preventing  loss  or  theft  in 
transit,  or  loss  in  dressing  due  to  the  admixture  of  a  large  pro- 
portion of  refuse.  Picking  of  this  kind  is  resorted  to  in  working 
rich  pockets  of  gold  or  silver  ore  under  the  superintendence  of  a 
foreman.  Pieces  of  pure  ozokerite  are  picked  out  by  the 
Boryslaw  miners  and  sent  to  the  surface  in  sacks,  and  the  men 
are  stimulated  to  do  the  work  as  thoroughly  as  possible  by  a 
premium  paid  for  the  clean  lumps. 

By  the  dim  light  of  a  candle  the  picking  process  cannot,  as  a 
rule,  be  carried  further  than  the  separation  of  worthless  rock,  and, 


542  ORE  AND  STONE-MINING. 

occasionally,  the  selection  of  some  very  rich  pieces  of  mineral ;  nor, 
if  the  light  were  better,  would  it  be  advisable  to  do  more,  for  the 
underground  traffic  would  be  complicated  if  a  number  of  classes  of 
mineral  were  made,  and  the  work  of  picking  can  be  better  per- 
formed by  keen-eyed  boys  and  girls  at  the  surface  than  by  the 
miners  underground,  especially  after  they  have  passed  middle  age. 
Picking  is  generally  carried  on  after  the  mineral  has  been 
subjected  to  a  washing  process  of  some  kind.  The  washed 
mineral  is  spread  out  on  a  table,  and  boys  and  girls,  standing  by 
the  side,  separate  the  stones  that  lie  before  them  according  to  their 
richness  and  the  subsequent  processes  they  will  have  to  undergo. 
A  scraper  made  of  a  piece  of  iron,  bent  as  shown  by 
FIG.  608.  Fig.  608,  assists  them  in  drawing  the  lumps  towards 
them  or  into  a  box,  waggon,  or  barrow  by  the  side  of 
the  table. 

In  a  lead-mine  we  may  have  («)  clean  galena ;  (b) 
mixed  ore,  i.e.,  pieces  consisting  partly  of  galena  and 
partly  of  barren  veinstone ;  (c)  barren  veinstone  and 
pieces  of  the  surrounding  rocks  (country).  This  is  a 
most  simple  case ;  but  very  frequently  one  has  to  deal 
with  a  deposit  producing  the  ores  of  two  or  three 
metals,  especially  in  the  case  of  lead  and  zinc,  and 
then  the  classification  into  various  qualities  becomes 
O  more  complicated. 

Where  the  amount  of  mineral  to  be  picked  is  con- 
siderable, labour  may  be  economised  by  self -discharging  tables, 
of  which  there  are  two  kinds — revolving  round  tables  and  tra- 
velling-belts. 

With  the  former  the  mineral  is  fed  on  at  some  point  of  the 
circumference  and  the  picking  is  done  by  boys  or  girls-  standing 
around.  They  select  pieces  of  certain  qualities  and  richness  as 
the  table  revolves  in  front  of  them,  and  finally,  when  a  revolu- 
tion is  all  but  completed,  nothing  remains  on  the  table  but  mineral 
of  one  quality,  which  is  swept  into  a  box  or  waggon  by  a  fixed 
projecting  scraper. 

Endless  belts  are  made  of  hemp,  wire-gauze,  or  steel  plates 
attached  to  endless  chains,  and  they  are  sometimes  as  much  as 
4  feet  wide.  The  refuse  is  picked  off  as  the  mineral  travels  by, 
and  the  clean  product  can  at  once  be  delivered  into  railway 
waggons,  ready  for  despatch  to  smelting  works  or  to  some  further 
process  of  dressing. 

(3)  BREAKING  UP,  SUBDIVISION,  OB  SHAPING. 
— Reduction  in  size  is  necessary  for  various  reasons.  Even  when 
an  ore  is  clean  enough  for  the  smelter,  the  large  lumps  are 
often  crushed  by  the  miner  for  the  sake  of  obtaining  a  fair  sample 
of  the  whole,  or  of  supplying  a  product  which  is  at  once  fit  for 
the  furnace.  Fertilisers,  cements  and  pigments  have  to  be  finely 
ground  before  they  can  be  used,  and  the  grinding  may  or  may 


DRESSING. 


543 


not  take  place  at  the  mine.  The  chief  object  of  breaking  up, 
however,  is  to  set  free  the  particles  of  ore,  which  are  generally 
found  enclosed  in  or  adhering  to  particles  of  barren  veinstone. 

Few  processes  in  dressing  are  of  more  importance  than  the 
proper  breaking  up  of  the  ore  or  other  mineral.  A  very  large 
number  of  machines  are  employed  suitable  for  the  different 
substances  which  have  to  be  treated,  and  it  will  be  impossible 

FIG.  609. 


RAGG/N  G. 


within  the  limits  of  this  chapter  to  do  more  than  pass  the  most 
important  in  review  in  a  somewhat  summary  manner. 

The  breaking  may  be  done  by  hand  or  by  machinery. 

The  processes  of  breaking  by  hand  may  be  divided,  according  to 
the  precise  object  in  view,  into  : 

a.  Breaking  with  the  sledge  hammer  [ragging  and  spatting]. 

b.  Cobbing. 

c.  Bucking. 

d.  Splitting. 

e.  Trimming  into  shape  with  the  saw,  axe,  hammer,  or  knife. 


544 


ORE  AND  STONE-MINING. 


a.  Breaking  with  the  Sledge  Hammer. — The  term 
"ragging"  is  applied,  in  Cornwall  (Fig.  609)*,  to  the  process  of 
breaking  up  the  very  big  lumps  (rocks)  as  they  come  from  the 
mine  by  a  large  sledge  hammer  weighing  about  10  or  12  Ibs.  The 

FIG.  6 10. 


SPELLING  . 

work  is  done  by  men,  who,  in  addition  to  breaking  the  lumps, 
may  separate  the  broken  pieces  into  various  categories  according 
to  quality. 

Spatting  is  work  of  a  similar  nature,  but  performed  with  a 
smaller  sledge,  weighing  4  or  5  Ibs.,  which  in  Cornwall  can  be 
wielded  by  a  woman  (Fig.  610).  Sometimes  there  is  a  little 

FIG.  6n. 


COBBING. 

picking  at  the  same  time.      The  process  of   spalling  is  often  a 
preliminary  to  crushing  by  stamps  or  rolls. 

b.  Cobbing. — Cobbing  is  a  special  kind  of  breaking  with  a 
small  hammer,  in  which  the  blow  is  directed  with  the  object  of 
knocking  off  a  piece  of  poor  rock  from  a  lump  of  mixed  ore  and 
refuse.  The  work  is  usually  performed  by  women  (Fig.  611), 

*  Henderson,  "  On  the  Dressing  of  Tin  and  Copper  Ores  in  Cornwall," 
Proc.  Inst.  G.E.,  vol.  xvii.,  1857-58,  plate  7. 


DRESSING. 


545 


girls,  or  boys,  who  commonly  sit  down  and  strike  the  lumps  upon 
an  anvil  of  some  kind,  often  an  old  stamp-head.  As  the  lumps 
are  held  in  position  by  the  left  hand,  a  badly  directed  blow  may 


FIG.  612. 


FIG.  613. 


BUCKING      MILLS. 

cause  a  nasty  wound ;  to  prevent  injuries  of  this  kind,  the  girls 
formerly  employed  in  cobbing  copper  ore,  at  the  Mona  and  Parys 
mines  in  Anglesey,  wore  pieces  of  iron  around  their  fingers,  and 
short  pieces  of  india-rubber  tube  are  used  for  the  same  purpose. 

c.  Bucking. — Bucking   is    breaking  with 
a  very  broad  flat  hammer  in  order  to  reduce 
an  ore  to  coarse  powder.     The  hammer,  called 
a  "bucking-iron,"  is  about  4  inches  square 
with  a  steel  face  ;  the  handle  is  from  18  inches 
to  2  feet  long.   The  ore  is  struck  upon  a  thick 
flat  plate  of  iron  (Fig.  612). 

d.  Splitting. — Splitting  is  required  with 
slate,  and  also  with  stone  which  will  rend 
along  certain  directions  other  than  cleavage 
planes,  such  as  planes  of  bedding.     It  is  done 
with  a  wedge  of   some  kind,   increasing    in 
sharpness  with  the  thinness  of  the  slice  re- 
quired.     Blocks   of   slate   are   split   by   the 
Welsh  quarrymen  with  a  stout  wedge  into 
slabs  about  3  inches  thick,  and   the  process 
is  then  repeated  with  a  thin  one  ("  cyn  maen 


hollti")  (Fig.  613)  until  they  obtain  a  roofing 
more  than  y  or  ^  inch  thick. 


material  often  not 


2  M 


546  OKE  AND  STONE-MINING. 

e.  Trimming. — Trimming  into  shape  is  necessary  with  many 
kinds  of  stone.  Thus  the  Bath  freestone  is  resawn  by  hand  at 
the  surface  (Fig.  156),  if  the  blocks  are  not  quite  suitable  for  the 
market  as  they  come  from  the  mine.  The  hearthstone  raised  at 
Godstone  in  Surrey  is  hewn  into  neat  blocks  by  a  peculiar  double- 
headed  axe,  whilst  paving- stones,  chert,  and  gun-flints  are 
fashioned  with  the  hammer ;  roofing-slate  is  chopped  into  rect- 
angular pieces  with  a  large  knife. 

Many  of  these  hand-processes  are  gradually  disappearing, 
owing  to  the  introduction  of  machinery  which  will  perform  the 
work  with  a  saving  of  time  and  labour. 

Machines  for  breaking  up,  subdividing,  or  shaping  ores  and  stone 
may  be  classed  as  follows : 

a.  Breakers  with  reciprocating  jaws. 

b.  Stamps. 

c.  Kolls. 

d.  Mills. 

e.  Edge-runners. 
/.  Ball-grinders. 
g.  .Disintegrators. 

h.  Conical  grinders  and  breakers. 
i.  Centrifugal  grinders. 
j.  Pneumatic  pulverisers. 
k.  Miscellaneous  pulverisers. 
I.  Sawing  machines. 
m.  Planing  machines. 
n.  Slatemaking  machines. 

a.  Jaw-breakers. — These  machines,  often  called  rock-breakers 
and  stone-breakers,  crack  stones  by  the  near  approach  to  one 
another  of  two  powerful  iron  or  steel  jaws.  The  best  known 
stone-breaker  is  the  machine  invented  by  Blake,  which  has 
rendered  inestimable  services  to  the  miner  for  the  last  thirty 
years,  and  the  introduction  of  which  constituted  a  most  important 
step  in  advance  in  the  art  of  ore-dressing.  Its  mode  of  action  is 
very  simple.  When  the  shaft  A  (Fig.  614)  revolves,  an  eccentric 
raises  the  pitman  B,  and  by  means  of  the  toggle-plates  C  C  causes 
the  movable  jaw  D  to  approach  the  fixed  jaw  E,  and  so  crack  any 
stones  lying  between  them.  During  the  descent  of  the  pitman  the 
jaw  D  is  drawn  back  by  an  india-rubber  spring.  The  jaws  are 
usually  toothed,  the  ridges  of  one  jaw  being  opposite  the  grooves  of 
the  other  when  the  machine  is  employed  for  breaking  stones  at 
mines ;  if  the  object  is  to  make  road-metal,  the  two  sets  of  ridges 
are  brought  opposite  each  other.  The  wearing  parts  of  the  two 
jaws  E  E  and  D  D  are  replaceable,  and  if  these  castings  cannot  be 
immediately  obtained  in  a  distant  country,  it  is  possible  to  do 
good  work  with  flat  plates  of  steel. 

The  stone-breaker  used  at  mines  commonly  has  the  renewable 
part  of  each  jaw  made  of  one  casting  instead  of  two  as  represented 
in  the  figure.  The  distance  between  the  two  jaws,  and  conse- 


DRESSING. 


547 


quently  the  fineness  of  the  product,  can  be  regulated  by  raising 
or  lowering  the  wedge-piece  on  the  right-hand  side  of  the  figure, 
or  by  inserting  other  toggle-plates. 

The  Blake  rock-breaker,  with  the  improvements  introduced  by 
Marsden,  is  made  in  various  sizes,  so  as  to  take  stones  as  large  as 
34  inches  by  18  inches;  the  smallest  machine  is  10  inches  by  8 
inches  in  the  mouth. 

Various  similar  machines  are  in  the  market.  Baxter  claims  that 
he  produces  fewer  small  chips  and  less  dust — matters  of  import- 
ance in  making  road-metal — by  his  so-called  "  knapping-motion." 
Marsden  has  a  breaker  with  what  he  calls  a  "  lever  motion,"  in 
which  the  toggle-plate  moving  the  jaw  forwards  is  impelled  by  a 

FIG.  614. 


bent  lever  worked  by  crank.  Hall  has  two  movable  jaws  placed 
side  by  side  which  act  alternately ;  as  all  the  parts  are  balanced, 
less  power  is  said  to  be  required  to  drive  it.  Lester's  machine  is- 
very  simple,  as  the  moving  jaw  is  driven  directly  by  the  pitman 
without  the  intervention  of  any  toggle-plates. 

For  crushing  to  finer  sizes,  Marsden  has  an  ingenious  pulveriser. 
It  resembles  his  stone-breaker  by  having  two  jaws,  one  fixed  and 
the  other  movable,  but  the  moving  jaw  has  a  rubbing  as  well  as  a 
squeezing  action.  The  machine  is  supplied  with  a  sieve,  so  that 
any  part  of  the  product  not  fine  enough  for  use  is  returned 
automatically  so  as  to  be  recrushed. 

The  Dodge  crusher  (Fig.  615*)  differs  from  those  just  described 

*  Copied  by  permission  from  a  paper  by  Mr.  A.  H.  Curtis,  which  may  be 
consulted  with  advantage  by  those  who  desire  information  on  the  subject 
of  crushing :  "  Gold-quartz  Keduction,"  Proc.  Inst.  C.  E.,  vol.  cviii.,  1891-92, 
p.  108.  Further  details  are  given  by  Professor  Egleston  in  his  useful 
paper,  "California  Stamp  Mills,  "Engineering,  vol.  xli.,  1880,  pp.  19,  85, 
163,  256 


548  ORE  AND  STONE-MINING. 

in  having  the  moving  jaw  pivoted  below,  instead  of  above. 
Consequently  the  effect  of  the  stroke  is  felt  most  at  the  top. 
One  object  of  this  arrangement  is  to  obtain  a  more  uniform 
product  than  is  possible  with  a  constantly  varying  discharge  orifice, 
like  that  of  the  Blake  breaker. 

FIG.  615. 


THE     DODGE       CRUSHER. 

b.  Stamps. — Though  used  at  mines  for  several  centuries, 
stamps  still  hold  their  own  in  spite  of  many  competing  forms  of 
crushing  machinery.  The  simplest  mode  of  describing  stamps 
is  to  say  that  they  are  pestles  worked  by  machinery  in  large  mortars. 
In  most  instances  the  blow  of  the  pestle  is  caused  by  its  mere 
weight,  sometimes  a  spring  is  added,  and  occasionally  the  action  of 
gravity  is  aided  by  compressed  air,  or  by  steam  pressure.  We 
thus  have  four  kinds  of  stamps : 

a.  Gravitation  stamps. 
/3,  Stamps  with  spring. 
7.  Compressed  air  stamps. 
5.  Steam-hammer  stamps. 

A  little  study  of  the  accompanying  figures  (616-620*)  will 
explain  the  most  important  characteristics  of  a  modern  stamp- 
battery. 

a.  A  A  (Fig.  6 1 6)  are  blocks  of  timber  forming  the  solid  founda- 
tion, which  is  required  on  account  of  the  heavy  pounding  action  of 
the  machinery ;  B  B,  the  transverse  sills,  with  the  battery-posts 
C  C,  the  braces  E  and  the  tie- timbers  D  D  form  the  framework 
holding  the  mortar  or  battery-box  (kofer,  Cornwall)  F,  in  which 
the  mineral  is  pounded  by  any  one  of  the  five  stamps  moving 
up  and  down  in  it.  G  is  a  perforated  plate  or  screen  which  pre- 
vents the  mineral  from  leaving  the  mortar  until  it  has  been 
brought  down  to  the  required  degree  of  fineness.  H  is  the  shaft 
carrying  cams,  which  lift  the  stems  by  tappets ;  K  K  are  the 
ends  of  the  stems  or  lifters  of  the  stamps  proper;  L  is  the 
pulley  through  which  motion  is  transmitted  to  the  cam  shaft  by 

*  Curtis,  Op.  cit. 


DRESSING. 


549 


the  belt  upon  the  driving  pulley  M.     N  is  the  gear  by  means  of 
which  the  driving  belt  can  be  tightened. 


FIG.  616. 


10    STAMP     BATTERY,    WOO 


Each  stamp  proper,  K  K,  consists  of  a  turned  rod  of  iron  with 
tapering  ends,  either  of  which  will  fit  into  a  corresponding  hole 
in  a  cast-iron  cylinder  known  as  the  "  head"  (Figs.  "617  and  620). 

FIG.  620. 


FIG.  617. 


FIG.  618. 


FIG.  619. 


SINGLE     DISCHARGE  MORTAR. 


The  conical  hole  or  socket  in  the  bottom  of  the  head  receives  the 
shank  of  the  "shoe,"  which  is  made  of  cast-iron,  cast-steel,  or 
forged  steel.  When  worn  the  shoe  can  be  removed  from  the  head 


OEE  AND  STONE-MINING. 


by  driving  a  steel  key  into  a  slot  above  it  (Fig.  620),  and  the  stem 
or  lifter  is  extracted  in  a  similar  manner  by  means  of  a  second 
.  slot  at  right  angles  to  the  first. 

The  mortar  is  shown  on  a  larger  scale  in  Fig.  617.  It  is  a 
cast-iron  box  with  an  opening  E  at  the  back  for  feeding,  and  one 
in  front,  into  which  is  wedged  the  frame  F  of  the  screen.  Some- 
times there  is  a  screen  behind  as  well  as  one  in  front,  or  screens 
at  both  ends  as  well  as  at  the  two  sides. 

Fig.  618  represents  the  tappet,  a  hollow  cylinder  of  cast-iron, 
which  is  fastened  to  the  lifter  by  steel  keys  and  a  gib.  The  gib  is 

a    piece   of   wrought-iron  fitting  the 
FIG.  621.  curved  surface  of  the  lifter  and  capable 

of  being  jammed  against  it  tightly 
when  steel  keys  are  driven  into  three 
holes  in  the  tappet.  As  the  shaft  H 
revolves,  the  cams  (Fig.  619)  lift  the 
tappets,  and  at  the  same  time  cause  a 
slight  rotation  of  the  stamp,  which 
conduces  to  regular  and  even  wear. 

The  head  B,  with  its  shoe  C  (Fig. 
617),  drops  upon  a  cylinder  of  similar 
metal  known  as  the  die,  and  it  is  be- 
tween C  and  D  that  the  mineral  is 
pulverised.  Both  shoe  and  die  wear 
away  and  have  to  be  changed  from 
time  to  time.  The  worn  shoe  and  die 
represented  in  Fig.  621  were  reckoned 
to  have  stamped  150  tons  of  gold 
quartz  at  the  Morgan  mine,  North 
Wales,  before  they  were  given  up  ; 
they  were  made  of  Fraser  and  Chal- 
mers' forged  steel.  The  order  in 
which  the  heads  drop  is  not  invariable; 
the  object  of  any  arrangement  is  to 
make  each  head  do  its  fair  share  of 

work.  Egleston  mentions  six  different  orders  of  dropping  which 
are  in  use,  and  this  shows  how  much  opinions  are  divided  on  the 
subject.  Among  them  may  be  mentioned  3,  4,  5,  2,  i,  and  i, 

5>  2»  4,  3- 

The  screens  through  which  the  pulverised  mineral  has  to  pass 
are  made  of  punched  iron,  steel,  or  copper  plates,  and  occasionally 
of  wire  gauze.  The  holes  are  round,  or  in  the  form  of  long  narrow 
slots.  The  size  of  the  holes  is  better  expressed  by  their  actual 
dimension  than  by  their  number  per  linear  inch  or  centimetre. 

The  total  weight  of  each  stamp  when  new,  that  is  to  say  stem, 
head  and  shoe,  varies  from  500  to  950  Ibs. ;  weights  of  700  to 
800  Ibs.  are  common.  The  precise  height  and  number  of  the  drops 
are  further  points  requiring  consideration ;  the  height  varies 


DRESSING.  551 

generally  from  8  to  n  inches,  and  there  are  70  to  100  drops 
per  minute.  Ore  may  be  stamped  dry  or  wet ;  in  the  latter  case, 
water  constantly  flowing  into  the  mortar-box  carries  oft'  the 
mineral  through  the  screens  in  the  form  of  a  muddy  stream 
known  as  "  pulp."  Egleston  reckons  that  the  quantity  of  water 
used  in  wet  stamping  is  from  |  to  ^  cubic  foot  per  stamp  per 
minute,  or  200  to  300  cubic  feet  per  ton  of  rock  stamped. 

The  quantity  stamped  per  head  per  day  must  necessarily  vary 
within  very  wide  limits,  according  to  the  weight  of  the  stamps, 
the  nature  of  the  stone  treated,  and  the  degree  of  fineness  desired. 
Speaking  roughly,  it  may  be  said  that  each  head  will  stamp  2  tons 
per  24  hours  and  require  2  h.-p. 

Regular  feeding  is  of  much  importance,  and  several  automatic 
arrangements  can  be  applied  to  the  battery  for  securing  the 
desired  result.  Most  frequently  a  tappet  upon  one  of  the  stems 
comes  into  play  when  the  stamp  has  a  longer  drop  than  usual, 
owing  to  want  of  ore  under  it,  and  strikes  a  lever  which  brings 
the  ore-feeding  contrivance  into  action. 

j3.  Spring  stamps  are  but  little  used.  Patterson's  "  Elephant " 
stamps  belong  to  this  class :  the  object  of  the  inventor  was  to  secure 
a  stronger  and  quicker  blow  than  would  be  given  by  a  mere  fall, 
and  so  enable  a  small  machine  to  do  more  work  than  would  be 
possible  if  gravitation  were  acting  alone.  The  stamp  is  worked 
by  a  crank,  and  interposed  between  the  striking  head  and  the 
connecting  rod  there  is  a  strong  spring,  which  assists  by  its  recoil 
and  allows  for  the  varying  height  of  the  ore  in  the  battery-box. 

y.  Husband's  pneumatic  stamps  were  designed  with  the  same 
intention — viz.,  a  quicker  and  a  harder  blow.  The  stem  or  lifter  of 
the  stamp  is  attached  to  a  piston  working  in  a  cylinder  which  is 
lifted  rapidly  up  and  down  by  a  crank.  There  are  holes  in  the 
cylinder  which  allow  the  air  to  escape  during  the  middle  of  the 
stroke,  but  after  it  has  been  raised  beyond  a  certain  point, 
the  air  below  the  piston  becomes  compressed  and  the  stamp  is 
lifted.  The  cylinder  in  its  downward  course  travels  quicker  than 
the  stamp  would  fall,  and  compressing  the  air  above  the  piston 
helps  to  drive  it  down  and  with  it  the  stamp ;  it  thus  increases 
the  force  of  the  blows,  which  can  be  given  at  the  rate  of  140  per 
minute.  Though  good  results  have  been  obtained  in  some  cases, 
these  stamps  have  not  made  their  way  into  general  use,  for  mining 
engineers  seem  to  consider  that  the  simplicity  of  the  ordinary 
stamps,  and  the  ease  with  which  any  slight  defects  can  be  repaired, 
make  up  for  the  disadvantages  which  Husband  tried  to  remedy. 

8.  We  now,  lastly,  come  to  the  steam-hammer  stamp,  which  has 
proved  a  most  efficient  machine  at  the  Lake  Superior  mines  for 
the  treatment  of  rock  containing  native  copper.  The  first 
stamps  of  this  kind  were  constructed  by  Ball  in  1856 ;  since  then 
great  improvements  have  been  made,  and  the  present  Leavitt 
stamp  will  crush  250  tons  of  copper-bearing  rock  in  24  hours. 


552 


ORE  AND  STONE-MINING. 


The  Ball*  stamp  (Fig.  622)  consists  of  a  vertical  steam-cylinder, 
C,  with  the  stamping  head  attached  to  the  piston-rod.  The 
various  parts  are  designated  as  follows : — D,  cast-iron  die ;  E, 
cast-iron  shoe ;  F,  frame  of  mortar ;  G  G,  grates  of  punched 
sheet  steel;  H  H,  cast-iron  head  posts;  L,  cast-iron  sills  or 
girders;  M,  cast-iron  mortar;  P,  pulley  by  which  the  valve  is 

FIG.  622. 


SCALE. 


FT  1     0 


IS  FEET 


M.I       0*      0 


4  MET  RES 


driven  ;  R  R,  cross  sills ;  S,  shoot  supplying  the  ore  ;  T  T,  spring 
timbers ;  U,  "  urn  "  or  cistern  supplying  water ;  Y  V,  cast-iron 
lining  plates,  resting  upon  a  cast-iron  ring  surrounding  the  die ; 
Y,  pulley  by  which  the  stamp  is  rotated. 

The  slide-valve  is  worked  from  the  pulley  P  by  the  elliptical 
spur-wheels  indicated  by  the  dotted  lines ;  the  valve  is  opened 
fully  for  making  the  down-stroke,  and  the  pressure  of  the  steam 

*  Ruthbone,  "On  Copper  Mining  in  the  Lake  Superior  District,"  Proc. 
Inst.  Mech.  Eng.,  1887,  p.  9(3. 


DRESSING. 


553 


FIG.  62?. 


greatly  increases  the  blow  due  to  gravity,  but  for  making  the 
up-stroke  the  steam  is  admitted  sharply,  and  in  just  sufficient 
quantity  to  lift  the  head. 

The  peculiarity  of  the  Leavitt  *  stamp  lies  in  the  differential 
steam-cylinder  (Fig.  623).  There  are  two  cylinders,  one  above 
the  other :  a  large  one  A  with  a  piston  B,  above  a  small  one  C 
with  a  piston  D.  Steam  is  admitted  on  to  the  top  of  piston 
B  through  the  valve  at  E,  and  is  exhausted  through  a  valve  at 
F  into  the  condenser.  The  space  under  the  piston  D  in  the 
cylinder  C  as  well  as  the  annular  space  G 
is  filled  with  steam  admitted  through  the 
opening  H,  and  kept  by  a  regulator  at  a 
uniform  pressure  sufficient  to  raise  the 
stamp.  The  stamp  is  thus  lifted  by  the 
lower  piston,  and  is  forced  down  by  the  large 
upper  one  against  the  constant  pressure 
exerted  by  the  lower.  The  valves  regu- 
lating the  admission  of  the  steam  and  the 
exhaust  valves  are  worked  by  cams  upon  a 
shaft  driven  by  a  belt  from  some  independ- 
ent source  of  power.  The  cams  which 
open  the  steam  and  close  the  exhaust  valves 
are  fixed,  but  the  cams  which  close  the 
admission  of  steam  and  open  the  exhaust 
can  be  adjusted  at  pleasure. 

The  moving  parts  of  each  Leavitt  stamp 
at  the  Calumet  and  Hecla  mine  weigh  about 
5000  Ibs.,  and  the  blow  is  struck  with  a 
velocity  of  20  to  22  feet  per  second.  The 
number  of  blows  is  98  per  minute ;  the  screens  are  made  of  the 
best  steel  -^  inch  thick,  punched  with  round  holes  ~3g-  inch  in 
diameter,  and  speaking  roughly  about  10  tons  of  rock  an  hour 
are  stamped  fine  enough  to  pass  through  them,  and  are  carried 
away  by  water  to  the  concentrating  machinery. 

c.  Rolls. — Rolls  were  introduced  into  the  West  of  England  in 
the  early  part  of  the  present  century  to  replace  bucking  by  hand. 
They  are  a  pair  of  smooth,  fluted,  or  toothed  cylinders,  made  of 
cast-iron  or  steel,  which  revolve  in  opposite  directions,  and  crush 
any  stone  which  is  allowed  to  fall  between  them. 

The  cylinders  or  rolls  are  generally  from  i  foot  to  3  feet  in 
diameter,  and  i  foot  to  3  feet  wide ;  they  are  kept  pressed 
together  by  levers  or  springs.  For  crushing  metallic  ores,  the 
diameter  of  the  roll  is  generally  from  two  to  three  times  its 
width. 

The  original  form  of  crushing  rolls,  and  one  still  largely  used 

*  F.  G.  Cogging,  "Notes  on  the  Steam  Stamp,''  Engineering,  vol.  xli., 
1886,  pp.  119,  130,  200. 


554 


ORE 


STONE-MINING. 


in  this  country,  is  represented  in  Fig.  624,  in  which  the  letters 
have  the  following  meanings :  G,  hopper,  into  which  the  ore  is 
shovelled  from  the  floor,  H  H ;  A  B,  the  two  cylinders  or  rolls 
shown  on  a  larger  scale  in  Fig.  625.  The  roll  B  has  plummer- 
blocks  which  can  slide  along  a  bed-plate,  and  so  allow  the  opening 
between  it  and  the  roll  A  to  be  increased  or  diminished ;  C  is  a 
bent  lever,  to  one  end  of  which  is  attached  a  weighted  box,  whilst 
the  other  constantly  presses  a  pin  against  the  plummer-block 
of  B;  the  crushed  rock  after  leaving  the  rolls  falls  into  a 
revolving  cylindrical  sieve.  All  that  fails  to  pass  through  the 
sieve  drops  into  the  "  raff- wheel "  E,  which  has  buckets  on  the 

FIG.  624. 


face  turned  towards  the  crusher ;  these  carry  up  the  coarse 
fragments  as  the  wheel  revolves  and  tip  them  on  to  a  sloping 
apron  F,  whence  they  fall  again  into  the  hopper  G  to  undergo  a 
further  crushing.* 

One  end  of  the  shaft  of  the  roll  A  is  coupled  to  the  main  driving 
shaft  of  the  machine,  which  carries  the  raff- wheel ;  the  other  end 
has  a  cog-wheel  which  gears  into  a  similar  one  on  the  shaft  of  B, 
and  so  drives  it.  The  inclined  sieve  is  driven  from  the  shaft 
of  A  by  means  of  bevel  gearing. 

An  improved  form  of  the  Cornish  rolls  has  been  introduced  by 
Krom,f  and  is  meeting  with  approval.  His  improvements  are: 

*  Ferguson,  "  On  the  Mechanical  Appliances  used  for  Dressing  Tin  and 
Copper  Ores  in  Cornwall,"  Proc.  Inst.  Mech.  Eng.,  1873,  plate  liv.,  and 
p.  133. 

t  Krom,  "  Improvements  in  Ore-crushing  Machinery,"  Trans.  Amer*  Inst. 
M.  E.,  vol.  xiv.,  1885,  p.  497. 


FIG.  626. 


DRESSING.  555 

Steel  tires,  pulley  gearing,  housing 
to  enclose  the  rollers,  swinging 
pillow-blocks,  tie-bolts  to  take  the 
crushing  strain,  hopper  for  auto- 
matically ensuring  a  regular  feed. 

The  tires  (Fig.  626)  are  made  of 
mild  forged  steel,*  and  are  held  by 
two  cores  in  the  form  of  truncated 
cones.  One  of  the  cores  is  shrunk 
firmly  on  to  the  main  shaft,  the 
other  is  split  on  one  side,  but  when 
drawn  in  towards  its  fellow  by 
bolts,  it  grips  the  shaft  very  tightly, 
and  at  the  same  time  fastens  the 
tire  securely.  The  main  shaft  (Fig. 
62 7)  f  is  driven  by  a  pulley,  indi- 
cated by  the  dotted  line,  revolving  at  the  rate  of  80  to  100  times 

FIG.  627. 


lNS.12 


CLCIMC.TRE.SIO 


SCALE.S 

3 


7  FEET. 


i  METRE. 


*  Messrs  Bowes  Scott  and  Western  use   a  special  steel  of  their  own 
which  is  said  to  be  exceedingly  durable.  t  Curtis,  op.  ctt. 


556  ORE  AND  STONE-MINING, 

a  minute ;  the  other  shaft  is  driven  at  the  same  speed,  but  in  the 
opposite  direction,  by  crossing  the  driving  belt  of  the  smaller 
pulley.  The  bearing  of  the  shaft  of  the  movable  roll  is  carried 
by  a  swinging  pillow-block  pivoted  underneath,  and  constantly 
drawn  towards  the  other  roll  by  the  strong  spiral  springs.  The 
upper  part  of  the  figure  represents  the  bottom  of  the  hopper 
which  supplies  the  rolls,  and  the  oscillating  feed-tray,  set  in  motion 
by  an  excentric. 

Actual  experience  extended  over  a  considerable  time  has  proved 
that  a  pair  of  Krom  rolls  at  the  Bertrand  Mill,  in  Nevada,  will 
crush  150  tons  of  quartzose  silver  ore  in  24  hours,  so  as  to 
pass  through  a  screen  with  16  holes  to  the  linear  inch.  It 
is  claimed  that  less  fine  dust  is  produced  with  these  rolls  than 
with  stamps,  a  matter  of  importance,  owing  to  the  losses  in  dress- 
ing or  lixiviation  when  there  is  a  large  proportion  of  slime. 

Fluted  rolls  are  used  in  crushing  rock-salt,  and  toothed  rolls 
are  used  for  breaking  comparatively  soft  minerals  such  as  rock- 
salt  or  gypsum,  and  even  hard  stone  for  road-metal.  Some  of  the 
rolls  for  rock-salt  are  made  of  toothed  rings  threaded  upon  a 
shaft,  and  the  two  rolls  are  arranged  so  that  the  teeth  of  one  lie 
between  those  of  the  other. 

d.  Mills. — The  term  "  mill "  has  a  very   vague  signification 
among  miners ;  all  sorts  of  machines  employed  in  crushing  arid 
grinding  are  commonly  known  as  mills.     I  propose  to  restrict  the 
term  to  grinders,  in  which  the  working  parts  consist  of  flat  or 
approximately   flat   surfaces,  one  of  which  revolves.     They  are 
called  into  requisition  for  reducing  a  mineral  to  a  fine  state  of 
division. 

The  typical  mill  of  this  class  is  the  well-known  fl.our  mill,  made 
of  two  horizontal  cylindrical  stones,  one  fixed,  the  other  revolving  ; 
sometimes  it  is  the  lower  stone  that  is  fixed,  sometimes  the  upper. 
Mills  of  this  kind  serve  to  grind  barytes  and  fertilisers.  The 
stones  are  generally  the  French  burr,  and  have  to  be  dressed 
from  time  to  time  as  they  wear.  The  mineral  is  fed  in  at  the 
centre,  and  is  discharged  at  the  circumference.  Instead  of  one 
top  stone,  there  may  be  several  separate  pieces;  this  combina- 
tion forms  the  "  arrastra  "  employed  for  grinding  and  amalgama- 
tion. 

When  the  mill  is  made  of  iron,  with  iron  or  steel  replaceable 
wearing  parts,  it  is  generally  called  a  "  pan  "  ;  like  the  arrastra,  it 
serves  for  fine  grinding  and  amalgamating. 

Millstones  need  not  necessarily  be  arranged  horizontally ;  the 
first  grinding  of  phosphate  of  lime  is  sometimes  done  by  stones 
set  vertically,  the  moving  stone  being  fixed  upon  a  horizontal 
axis. 

e.  Edge-runners. — The  edge-runner  is  a  cylinder  turning  upon 
a  horizontal  axis  which  is  made  to  revolve  around  a  vertical  axis, 
In  its  simplest  form,  it  is  a  large  stone  wheel,  the  horizontal  axis 


DRESSING. 


557 


of  which  is  drawn  round  an  upright  post  by  a  mule.  The  stone 
crushes  by  its  weight,  and  as  it  has  to  slide  a  little  in  order  to 
keep  its  circular  path  upon  the  bed,  there  is  also  a  rubbing 
action.  This  primitive  form  of  edge-runner,  known  as  the  Chilian 
mill,  is  employed  in  crushing  and  amalgamating  gold  and  silver 
ores.  It  is  better  to  have  two  of  the  upright  wheels  at  opposite 
ends  of  the  horizontal  axis,  as  then  the  machine  will  work  more 
smoothly  (Fig.  628).  Each  wheel  is  made  of  a  strong  tire  of 
chilled  cast-iron  wedged  to  a  centre-piece  of  ordinary  cast-iron, 
and  the  bed  is  composed  of  sectors  of  chilled  cast-iron,  which  can 

FIG.  628. 


be  changed  when  they  are  worn.  The  driving  gear  may  be  above 
or  below. 

/.  Ball-grinders. — In  machines  of  this  class  the  mineral  is 
pulverised  by  its  contact  with  a  number  of  cast-iron  balls,  which 
are  constantly  rolling  against  each  other  when  the  case  containing 
them  revolves. 

Jordan's  Centrifugal  Grinder  and  Amalgamator  is  a  circular 
pan  set  upon  an  inclined  axis  with  a  few  large  iron  balls  like 
cannon-balls  which  lie  in  the  lowest  part ;  the  machine  is  supplied 
with  crushed  ore,  which  is  soon  ground  fine  and  escapes  through 
a  sieve  placed  around  the  outside  of  the  pan. 

The  ingenious  "  Grusonwerk  "  ball-grinder  (Figs.  629  and  630), 
now  made  by  Krupp,  has  a  continuous  feed  and  discharge.  It  con- 
sists of  a  horizontal  iron  cylinder  provided  with  several  curved  plates 


558 


ORE  AND  STONE-MINING. 


a  a,  which  carry  a  number  of  steel  balls.  The  stuff  which  is  fed  in  by 
the  hopper  h  falls  among  the  balls  and  is  ground  by  their  rubbing. 
During  each  revolution  of  the  drum,  they  drop  five  times  as  they 
come  to  the  edges  of  the  plates.  The  ground  mineral  passes 


through  holes  in  the  curved  plates  a  a,  and  in  the  cylindrical  sieve- 
c  made  of  punched  steel  plate  ;  it  now  meets  with  the  fine  wire 
gauze  sieve  d,  which  lets  through  all  that  is  sufficiently  pulverised 
into  the  hopper  s,  whence  it  can  be  drawn  off  at  pleasure.  The 
object  of  the  punched  steel  sieve  c  is  to  prevent  the  unnecessary 
wear  of  the  fine  wire  gauze,  which  would  naturally  suffer  if  it- 


DRESSING. 


559 


were  exposed  to  the  rubbing  of  coarse  particles.  The  stuff  which 
is  too  coarse  to  pass  through  the  fine  outer  sieve  d  is  collected  by 
plates  f  and  led  back  into  the  inside  of  the  drum,  where  it  is 
again  exposed  to  the  grinding  action  of  the  balls  ;  b  b  are  lining 
plates  to  prevent  the  wear  of  the  ends  of  the  cylinder ;  1 1  and  i 
denote  bars  closing  a  manhole  which  can  be  opened  after  the 
removal  of  the  sheet-iron  casing  surrounding  the  whole  machine. 

g.  Disintegrators. — Though  any  reduction  of  a  mineral  into 
fragments  or  powder  may  be  spoken  of  as  "  disintegration,"  th& 
word  disintegrator  has  been  appropriated  by  the  grinders  which 
do  their  work  with  revolving  bars  or  beaters.  The  best-known 
machine  of  this  class  is  Carr's  disintegrator  (Fig.  631).  It 


may  be  described  as  consisting  of  two  cylindrical  cages,  revolving 
one  inside  the  other  in  opposite  directions.  Each  cage  is  made  up 
of  two  concentric  sets  of  bars,  attached  to  a  disc  on  one  side  and 
to  a  ring  on  the  other.  The  stuff  which  is  fed  into  the  centre  is 
thrown  by  the  bars  a  a  of  the  cage  X,  against  the  bars  b  b  of  the 
cage  Y ;  thence  it  flies  against  the  outer  circle  of  bars  c  c  of  X,  and 
finally  against  the  outer  circle  of  bars  d  of  the  cage  Y.  It  then 
enters  the  circumferential  space  e,  whence  it  can  be  allowed  to- 
escape  by  a  suitable  opening  in  the  outer  casing/. 

It  is  claimed  for  this  machine  that  some  of  the  pulverising  is 
done  by  the  impact  of  the  particles  one  against  the  other,  and  that 
consequently  the  wear  of  the  steel  bars  is  less  than  might  be 
expected.  However,  the  disintegrator  is  found  most  fitted  for 
comparatively  soft  materials,  such  as  coal,  gypsum,  phosphates, 
and  rock-salt. 

Instead  of  being  arranged  in  the  form  of  concentric  circles  in 


ORE  AND  STONE-MINING. 

this  cage-like  manner,  the  beaters  are  sometimes  radial,  and,  when 
revolving  at  a  very  high  speed,  quickly  reduce  soft  minerals  to 
powder. 

h.  Conical  Grinders. — In  these  grinders  the  crushing  action 
is  usually  produced  by  the  revolution  of  a  toothed  cone, 
inside  a  toothed  cup;  they  thus  resemble  in  principle  the  old- 
fashioiied  coffee-mill.  The  Gates  crusher  (Fig.  632)  acts  differently. 
It  consists  of  an  outer  conical  shell  Q  (Fig.  632),  lined  with 
removable  plates  E,  around  which  travels  the  conical  breaking 


head  F  carried  by  the  upright  spindle  G  ;  both  E  and  F  are  made 
of  chilled  cast-iron.  The  lower  end  of  the  spindle  G  fits  loosely 
in  the  excentric  box  D,  and  is  a  little  out  of  the  centre ;  it  is 
supported  by  the  step  P,  which  can  be  raised  or  lowered  by  the 
screw  S,  in  order  to  regulate  the  distance  between  the  breaking 
head  and  the  shell,  and  consequently  the  fineness  of  the  crushed 
product.  The  upper  end  of  the  spindle  G  lies  loosely  in  a  socket 
in  the  top  framing  C.  The  belt-pulley  T  U  is  loose  upon  the 
shaft  X,  and  it  drives  it  by  means  of  the  clutch  V,  firmly  keyed 
to  X,  and  the  pin  W.  In  case  of  any  undue  strain,  the  pin  W 
breaks  and  prevents  damage,  for  the  machine  at  once  stops  until 
the  obstruction  is  removed  and  a  new  pin  has  been  inserted. 


DRESSING.  561 

The  bevel  pinion  upon  X  drives  the  bevel  wheel  L  with  its 
excentric  box ;  when  L  revolves,  the  lower  end  of  G  is  carried 
round  excentrically,  whilst  the  top  moves  in  its  socket.  The 
breaking  head  is  thus  made  to  approach  and  recede  from  each 
part  of  the  shell  in  succession,  producing  practically  the  same 
effect  as  the  reciprocating  jaw  of  the  Blake  machine.  The  loose 
collar  I  serves  to  keep  out  dust,  and  it  has  a  hole  J,  through  which 
the  machine  is  oiled  ;  N  N  are  holes  for  conveying  oil  to  the 
space  Y.  The  material  to  be  crushed  is  fed  in  through  three 
large  openings  in  the  top  frame  ;  it  falls  between  E  and  F,  is 

FIG.  633. 


INS  12 


SCALE 

3 


OEClMtTRLJIO 


crushed  by  the  movement  of  the  breaking  head  and  drops  through 
at  Q  Q  on  to  an  inclined  apron,  whence  it  slides  into  any  con- 
venient bin  or  receptacle. 

i.  Centrifugal  Grinders. — There  are  several  grinding 
machines  in  which  a  roller  is  whirled  round  upon  the  inside  of  a 
cylinder  against  which  it  presses  by  centrifugal  force.  The 
machine  of  this  class  most  largely  employed  is  the  Huntington 
mill  (Figs.  633  and  634).  A  vertical  shaft  G,  driven  by  bevel 
gearing  from  below,  carries  a  horizontal  frame,  which  supports 
four  grinding  rollers  by  the  yokes  Y  Y  lying  in  the  pockets  P. 
The  yoke  allows  a  radial  swing  of  the  crushing  roller  against  the 
steel  ling  (Fig.  634)  lining  the  pan  in  which  the  grinding  takes 
place.  The  construction  of  Paxman's  improved  roller  is  shown  by 

2  N 


562 


ORE  AND  STONE-MINING, 


Figures  635   to  637.     E.  is  a  steel  ring  which  does  the  actual 
grinding  and  is  renewable   when  worn ;    it  is  fixed  by   wooden 

FIG.  634. 


«•  ROLLER   HUMTINGTOK    MILL.B  FT  DIAMETER,  SECTIONAL  ELEVATION. 

SCALE: 

INS,  12  0  I  2  3  4.  56  7    FLtT 


DECIMLTRLi'O 


JETRL 


wedges  W  to  the  core  G,  and  a  sleeve  bolted  on  to  the  core  receives 
the   spindle   S.      From   this  explanation    it   will   be  seen   that 


FIG.  635. 


FIG.  636. 


FIG.  637. 


PLAN. 


PLAN  At  A.B. 


SCALE 


INS.12 


2  FEE 


10  DECIMETRES 
I i          i     '  .  i 


0 

I I 


SECTIONAL  ELEVATION. 

the  roller  can  revolve  round  the  spindle  S,  but  that  the  latter 
does  not  turn  upon  its  own  axis  when  it  is  carried  round  by  the 
revolving  frame  supporting  the  yokes.  A,  B,  C,  D  (Fig.  633)  are 


DRESSING.  563 

wooden  scrapers  which  force  the  ore  from  the  centre  to  the 
circumference  and  so  bring  it  under  the  action  of  the  rollers.  It 
is  easy  to  understand,  therefore,  that  when  the  shaft  G  revolves 
the  rollers  are  thrown  out  by  centrifugal  force  against  the 
annular  lining,  and  crush  and  amalgamate  the  ore.  The  stuff 
which  is  pulverised  sufficiently  fine  escapes  through  a  wire-gauze 
sieve  placed  on  the  side  of  the  pan,  just  above  the  lining  ring.  As 
this  sieve  has  not  to  resist  the  violent  blows  to  which  the 
screens  of  stamps  are  liable,  it  may  be  made  of  much  finer 
material. 

j.  Pneumatic  or  Air-current  Pulverisers.  —  In  one  of 
these  pulverisers,  it  is  proposed  to  crush  the  mineral  by  driving 
the  particles  violently  against  each  other  by  means  of  two  power- 
ful opposite  jets  of  air  or  superheated  steam.  To  use  a  familiar 
illustration,  it  may  be  said  that  stone  bullets  are  fired  from 
air-guns  against  each  other  with  such  force  that  they  break 
into  powder  upon  meeting.* 

The  Cyclone  Pulveriser,  which  excited  a  good  deal  of  interest 
.at  the  Paris  Exhibition  of  1889,  is  based  upon  the  same 
idea.  It  consists  of  two  beaters,  something  like  screw-propellers, 
•driven  at  a  speed  of  1000  to  3000  revolutions  per  minute 
in  opposite  directions  in  a  small  cast-iron  chamber  or  case,  in 
the  form  of  two  truncated  cones  joined  together  at  their  larger 
bases.  The  material  to  be  crushed  is  delivered  regularly  into 
this  case  by  mechanical  feeders,  and  the  whirlwind  created 
by  the  beaters  hurls  the  particles  against  each  other  with 
such  violence  that  they  are  almost  instantly  reduced  to  the 
state  of  impalpable  powder.  The  fine  dust  produced  in  this 
way  is  constantly  being  sucked  off  by  a  fan,  arid  allowed 
to  settle  in ,  chambers  whence  it  is  conveyed  mechanically 
into  hoppers.  It  can  then  be  drawn  off  into  sacks  as  required. 
As  the  aspirating  force  of  the  fans  can  be  regulated  at 
pleasure,  the  mineral  can  be  brought  to  any  desired  degree 
of  fineness  without  any  screening.  Before  treatment  in  this 
machine,  the  material  must  be  crushed  small  enough  to  be  set  in 
motion  by  the  hurricane-like  blast  of  the  beaters;  in  the  case 
of  a  mineral  like  quartz  the  fragments  must  not  be  larger  than 
walnuts. 

k.  Miscellaneous  Pulverisers. — These  are  so  numerous 
'that  it  is  out  of  the  question  even  to  think  of  giving  their  names. 
The  Sturtevant  mill  bears  some  resemblance  in  its  mode  of 
action  to  the  Cyclone  pulverisers,  inasmuch  as  the  particles  are 
flung  against  each  other  with  great  force  and  break  up  in 
mid-air,  so  to  say.  The  stones  are  projected,  however,  by  centri- 
fugal force  and  not  by  air-currents.  The  Sturtevant  mill  is  made 
•of  two  horizontal  hollow  cups  which  revolve  at  great  speed  in 

*  Industrial  Review,  vol.  i.,  1886,  p.  56. 


564  CUE  AND  STONE-MINING. 

opposite  directions.  The  mineral  is  fed  into  the  interval  between 
the  two  caps,  and  as  fast  as  it  makes  its  way  into  one  of  themr 
it  is  hurled  out  again  by  centrifugal  force  and  strikes  other 
fragments  which  are  thrown  across  by  the  opposite  cup.  The- 
powdered  mineral  is  drawn  off  through  a  screen  by  a  fan. 
Though  the  hurling  cups  are  cylindrical,  the  crushed  rock  packs 
itself  into  the  ends  and  forms  a  conical  stone  lining  which 
prevents  wear  upon  the  iron  surfaces.  The  Sturtevant  mill  is- 
said  to  be  largely  used  in  the  United  States  for  grinding 
phosphate  of  lime. 

The  crushing  machines  in  these  descriptions  have  been 
arranged  according  to  their  modes  of  construction ;  it  will  be  well 
to  point  out  in  conclusion  the  uses  to  which  they  are  applied,  viz. : 

1.  Preliminary  breaking  :  jaw-breakers,  and  Gates  rock  breaker. 

2.  Coarse  crushing  :  rolls. 

3.  Fine  crushing :  stamps,  rolls,  mills  of  various   descriptions, 

and  disintegrators. 

1.  Sawing  Machines. — These  are  necessary  in  the  case  of 
stone  and  slate.  The  simplest  machine  is  merely  a  plain  blade 
held  in  a  frame,  moved  backwards  and  forwards  by  a  crank  or 
excentric,  whilst  sand  or  chilled  cast-iron  shot  and  water  are  sup- 
plied to  aid  the  saw  in  its  cutting  work.  The  wire  saw,  already 
described  in  a  previous  chapter,  is  employed  for  the  same  purpose. 

FIG.  638. 


In  the  case  of  slate,  the  work  is  usually  done  with  circular  saws. 
The  blocks,  which  have  been  split  into  slabs  about  4  inches  thick, 
are  fastened  by  wedges  upon  a  sawing  table,  such  as  is  represented 
in  Fig.  638.  It  is  a  cast-iron  bed,  A  B,  moving  upon  rollers,  with 
holes  into  which  wedges  can  be  placed  for  fixing  the  slabs  of  slate. 
The  pulley  C  drives  the  circular  saw  D,  and  at  the  same  time 
gives  motion  to  a  chain  which  draws  the  table  along  from  one 
end  of  its  frame  to  the  other.  When  the  table  has  gone  as  far  as 
possible,  the  workman  turns  a  hand-wheel  which  reverses  the 
motion,  it  is  drawn  back,  and  another  set  of  slabs  are  arranged 
so  that  they  may  be  cut  when  it  again  moves  forward.  The 
saw  sometimes  lies  in  a  semicircular  trough  full  of  water,  which 
serves  to  keep  it  cool. 

m.  Planing. Machines. — Planing  machines,  somewhat  similar 


DRESSING. 


565 


to  those  used  in  engineering  shops,  are  employed  for  making  the 
smooth  slate-slabs  required  for  cisterns  or  billiard- tables.  The 
tool  is  held  in  one  direction  only  and  is  not  reversed  after  each 
stroke. 

n.  Slate-making  Machines. — Greaves'  circular  slate-dressing 
machine  (Fig.  639)  does  precisely  the  same  work  as  the  quarry- 
man's  knife.  It  is  a  frame  carrying  two  knives,  C,  which  are 
made  to  revolve  by  the  pulley  A  upon  the  same  shaft  as  the  little 
flywheel  B.  D  is  a  fixed  knife  and  E  a  cast-iron  arm  with  a 
number  of  notches  on  the  inside,  which  are  gauges  for  enabling  the 
quarryman  to  cut  the  slates  to  exact  sizes.  The  belt  pulley  A  is 
thrown  in  and  out  of  gear  by  a  clutch. 

Another  machine  for  doing  the  same  kind  of  work  acts  like  a 

FIG.  639. 


guillotine,  and  has  a  knife  which  slides  up  and  down  vertically 
between  guides.  In  both  machines  the  action  of  the  hand -knife 
is  imitated — that  is  to  say,  the  cut  is  made  gradually  along  the 
desired  line. 

.  (4)  AGGLOMERATION  OB  CONSOLIDATION.— Pro- 
cesses of  this  kind  are  more  particularly  used  in  the  case  of  coal 
or  brown  coal,  small  particles  of  which  can  be  pressed,  either 
with  or  without  the  addition  of  some  cementing  material,  into 
blocks  of  fuel  of  convenient  shapes  and  sizes.  At  the  same  time 
agglomeration  is  nob  confined  to  coal :  some  of  the  poor  clayey 
phosphate  of  lime  of  the  department  of  the  Somme  is  made  into 
bricks,  so  that  it  may  be  readily  burnt  in  kilns  and  deprived  of 
its  moisture  before  being  ground  or  sent  away;  the  so-called 
"  purple  ore,"  the  residue  after  the  treatment  of  cupreous  iron 
pyrites  by  the  wet  process,  and  other  kinds  of  fine  iron  ore,  are 
also  sometimes  made  into  bricks  for  the  purpose  of  obtaining  a 
product  suitable  for  smelting  in  the  blast-furnace. 


566  OKE  AND  STONE-MINING. 

In  order  to  get  rid  of  water,  washed  graphite  is  pressed  into- 
cakes,  which  are  then  ready  for  the  drying  stove. 

(5)  SCREENING  OR  SIFTING.— This  is  an  important 
branch  of  dressing.  Sometimes  it  is  a  preliminary  process  which 
is  necessary  or  advisable  previous  to  concentration  by  specific 
gravity,  or  to  picking  by  hand.  Sometimes  it  is  a  final  process- 
previous  to  sale,  and  for  several  reasons  :  the  purchaser  usually 
requires  cements,  pigments,  and  fertilisers  in  a  state  of  fine  sub- 
division and  free  from  any  coarse  particles,  or,  contrariwise,  he  may 
object  to  ores  in  the  form  of  "  smalls  "  or  dust,  which  would  choke 
his  smelting  furnaces.  Lastly,  in  a  case  of  coal,  which  is  beyond 
the  province  of  this  treatise,  the  consumer  prefers  lumps,  because 
they  burn  more  readily  than  dust  and  afford  a  rough  guarantee 
of  purity ;  whilst  with  anthracite  the  sifting  process  is  carried  out 
on  a  very  elaborate  scale,  in  order  to  obtain  suitable  kinds  of  fuel. 

Minerals  are  classified  according  to  size  by  means  of  sieves 
worked  by  hand  or  by  machinery. 

Hand-sieves  are  often  employed  underground  for  taking  out 
"  smalls "  which  are  not  acceptable  to  the  purchaser.  Thus  at 
the  Merionethshire  manganese  mines,  the  workmen  shovel  the 
fine  stuff  on  to  circular  hand-sieves  with  holes  |  inch  square,  and 
use  all  that  goes  through  as  material  for  filling  up.  In  speaking 
of  the  iron  ore  worked  opencast  in  Northamptonshire  a  similar 
separation  of  the  fine  was  mentioned  (Chap.  VI.,  p.  288). 

Sifting  by  hand  is  shown  in  Fig.  612  following  bucking,  so  as 
to  ensure  a  proper  degree  of  hand-crushing.  It  is  more  econo- 
mical to  employ  a  rectangular  sieve  fixed  in  a  steeply  sloping 
position,  and  throw  the  mineral  against  it  with  the  shovel.  In- 
clined gratings  (grizzlies,  U.S.)  formed  of  bars  of  flat  iron  or  steel, 
on  to  which  the  waggons  of  mineral  are  tipped  as  they  come  from 
the  mine,  are  another  form  of  sifting  apparatus. 

Machine-sieves. — Most  of  the  sizing  at  mines  is  performed  by 
sieves  set  in  motion  by  machinery ;  there  are  two  principal  kinds 
of  machine-sieves :  flat  oscillating  sieves  and  revolving  cylindrical, 
conical,  pyramidal,  or  spiral  sieves. 

The  most  common  in  ore  mines  are  revolving  sieves,  either  cylin- 
drical or  in  the  form  of  truncated  cones.  A  sieve  of  this  kind  is  often 
known  as  a  "  trommel."  The  word  is  expressive  enough  to  the 
German  ;  but  it  fails  to  tell  the  Englishman  that  the  machine  is 
drum-shaped,  and  it  can  be  tolerated  in  our  language  simply  on 
the  score  that  it  has  so  long  been  in  use  that  it  is  practically 
naturalised. 

The  sifting  is  done  by  wire  web  or  by  perforated  sheets  of  metal, 
either  iron,  steel,  copper,  brass,  or  bronze.  Figs.  640,  641  and  642 
represent  sieves  with  round  holes  1,2,  and  5  millimetres  respec- 
tively. The  holes  are  sometimes  square  or  oblong. 

The  trommel  consists  of  the  perforated  plate  or  the  wire  cloth 
bent  into  the  required  conical  or  cylindrical  form,  and  supported  by 


DKESSING. 


567 


rings  attached  by  arms  to  a  central  axis.  The  conical  trommel  has 
the  advantage  that  its  axle  can  be  placed  horizontal,  for  the  slight 
inclination  of  the  sieve  causes  the  mineral  to  make  its  way  from 
the  feed  or  smaller  end  to  the  discharge  or  larger  end,  provided 
of  course  that  the  machine  is  in  motion.  If  the  trommel  is 
cylindrical,  its  axis  must  be  inclined  in  order  to  secure  the  same 
result. 


FIG.  640. 


FIG.  641. 


FIG.  642. 


When  it  is  necessary  to  separate  a  crushed  mineral  into  a 
number  of  different  sizes,  the  trommels  are  commonly  arranged 
so  as  to  discharge  one  into  the  other.  This  plan  has  the  dis- 
advantage of  requiring  much  gearing  or  many  belts,  for  the 
sieves  have  to  be  arranged  step-fashion,  each  one  a  little  below 
its  predecessor.  If,  on  the  other  hand,  only  one  long  trommel 
is  used,  with  the  holes  increasing  in  size  from  the  feed  to  the 
discharge  end,  there  is  the  evil  of  letting  the  very  coarse  stuff 

FIG.  64205. 


SCALE 


2  METRO 


IZIN.       0 


9  FEET 


wear  away  the  fine  sieve,  and  cause  more  frequent  repairs. 
A  good  form,  made  by  Jacomety  and  Lenicque  of  Paris,  is 
that  shown  in  Fig.  64 2 a.  The  feed-end  A  is  free  from  cross-arms, 
having  a  large  cast-iron  ring  B  as  support,  and  there  are  in  all 
three  sieves  C,  E  and  F.  Suppose,  for  instance,  that  the  trommel 
is  supplied  with  stuff  which  has  left  a  crusher  sieve  with  no  particles 
bigger  than  8  millimetres  ( J  inch)  across ;  this  passes  011  to  the  inner 
sieve  C  with  holes  of  6  mm.  (J  inch).  The  next  ring,  D,  is  of  sheet 
iron.  In  this  way  the  coarsest  stuff  never  touches  the  fine  sieve. 


568 


ORE  AND  STONE-MINING. 


The  two  sieves,  E  and  F,  on  the  outside  have  holes  of  2  mm.  and 
4  mm.  Consequently  this  trommel  makes  four  classes  :  smaller  than 
2  mm.,  i.e.,  that  which  drops  through  the  finest  sieve,  E ;  size  2  to  4 
mm.,  dropping  through  sieve  F;  size  4  to  6  mm.,  discharged  at  G ; 
and,  lastly,  size  6  to  8  mm.,  which  passes  out  at  H.  An  objection 
to  trommels  with  concentric  sieves  is  the  difficulty  of  effecting 
repairs  inside,  if  the  plates  become  worn.  This  defect  is 
remedied  in  the  trommel  figured  by  fixing  on  the  perforated 
plates  •  with  screw  bolts ;  they  can  then  be  taken  off  quickly 
and  easily. 

II.  PBOCESSES    DEPENDING   UPON  PHYSICAL 
PROPERTIES. 

(i)  MOTION  IN  WATER. — Many  of  the  more  important 
dressing  processes  depend  upon  the  rate  at  which  particles  of  mine- 
rals fall  in  water.  The  velocity  of  fall  depends  upon  the  specific  gra- 
vity and  the  volume.  A  piece  of  galena  with  a  specific  gravity  of  7*5 
sinks  to  the  bottom  more  quickly  than  a  piece  of  quartz  of  equal 
bulk,  which  has  a  specific  gravity  of  only  2 '6.  Nevertheless, 
if  the  piece  of  quartz  is  large  enough,  it  will  fall  to  the  bottom  as 
fast  as  the  smaller  piece  of  galena  Particles  which  have  equal 
velocities  of  fall,  though  differing  in  size  and  specific  gravity,  are 
said  to  be  like-falling  or  equivalent. 

P.  von  Rittinger  *  gives  the  following  table  to  show  the  rates 
of  fall  of  spheres  of  three,  minerals  differing  considerably  in 
specific  gravity : 


jj* 

ti 

Velocity  in  Metres  after  the  Lapse  of 

SUBSTANCE. 

11 

1 

coo 

Q 

isec. 

isec. 

£  sec. 

i  sec. 

2  sec. 

Galena  .         

7*5 

mm. 
16 

0-903 

1*411 

1-630 

I  '650     I  '650 

Iron  pyrites  . 

5'° 

16 

0-825 

1*174 

1-287 

1*293 

1-293 

Quartz   .         .         .         . 

2-6 

16 

0-570 

0*767 

O'Soi 

0*817 

0-817 

Galena  .... 

7;s 

4 

0-704 

0*814 

0-823 

0*824 

0*824 

Iron  pyrites  . 

4 

0-586 

0*643 

0-646 

0-646 

0-646 

Quartz   .... 

2-6 

4 

0-383 

0*409 

0*409 

0-409 

0-409 

Galena  .... 

7'5 

i 

0-409 

0-413 

0*414 

0-414 

0-414 

Iron  pyrites  . 

5'o 

i 

0-321 

0-323 

0*323 

0-323 

0*323 

Quartz   .... 

2-6 

1 

0*203 

0-204 

0*204 

0-204 

0*204 

This  table  shows  that  the  particles  at  the  very  outset  have  an 
accelerated  velocity,  and  that  the  velocity  speedily  becomes 
uniform.  It  also  shows  that  a  small  sphere  of  quartz  4 

*  Lehrluch  der  Aufbereitungskundc,  Berlin,  1867,  p.  178. 


DRESSING. 


569 


FIG.  643. 


millimetres  in  diameter  sinks  down  at  almost  precisely  the  same 
rate  as  a  sphere  of  galena  only  i  millimetre  in  diameter.  These 
two  particles  are  therefore  like-falling  or  equivalent.  It  is 
evident  that  if  the  sphere  of  galena  has  a  greater  diameter  than  i 
millimetre  it  will  fall  faster  than  the  grain  of  quartz  which  is  4 
millimetres  across.  Consequently,  if  a  mixture  of  minerals 
differing  decidedly  in  densit}T  is  separated  by  sifting  into  lots 
consisting  of  particles  nearly  alike  in  size,  there 
is  no  difficulty  in  effecting  a  separation  by  their 
mere  descent  through  still  water. 

This  fact  may  be  rendered  very  plain  by  a 
simple  experiment.  Prepare  a  mixture  of  like- 
sized  grains  of  coal,  calc-spar,  and  galena  by 
sifting  the  pounded  minerals  and  retaining,  for 
instance,  the  portion  which  has  no  particles 
more  than  |  inch  in  diameter  or  less  than  y1^. 
Put  the  mixture  into  a  glass  tube  4  or  5  feet 
long  and  j  inch  or  i  inch  in  diameter,  corked 
at  one  end  (Fig.  643).  Fill  completely  with 
water  and  cork  the  other  end  ;  reverse  the  tube 
briskly  and  hold  it  upright.  The  galena  will 
fall  to  the  bottom  first,  then  the  calc-spar,  and 
lastly  the  coal,  and  the  three  minerals  will  form 
separate  layers  distinctly  marked  by  their 
differences  of  colour.  A  shorter  and  narrower 
tube  may  be  used,  but  the  greater  the  depth  of 
the  water  the  more  accurately  can  the  descent 
of  the  particles  be  watched. 

The  experiment  may  be  repeated  by  reversing 
the  tube,  for  the  galena  will  soon  make  up  by 
its  high  specific  gravity  for  the  slightly  longer 
path  which  it  has  to  travel. 

Though  the  final  velocity  attained  by  a  par- 
ticle of  a  mineral  falling  through  water  depends 
both  upon  its  volume  and  its  specific  gravity, 
it  is  nevertheless  true  that  in  the  early  part  of 
the  fall  the  influence  of  the  specific  gravity  preponderates,  and 
the  denser  particles  take  the  lead.  This  appears  from  the  table. 
Take,  for  instance,  a  particle  of  quartz  16  millimetres  in  diameter 
and  one  of  galena  of  4  millimetres,  which  are  practically  like- 
falling  after  the  lapse  of  a  second ;  at  the  end  of  |  second,  on  the 
other  hand,  the  galena  is  falling  with  a  velocity  2  5  per  cent,  greater 
than  that  of  the  quartz.  This  fact  is  utilised  in  practice,  for 
instead  of  simply  letting  the  mixture  of  minerals  fall  through 
a  certain  depth  of  still  water,  it  is  made  to  undergo  a  rapid 
succession  of  very  small  falls.  In  this  manner,  particles  vary- 
ing in  specific  gravity  can  be  separated  into  distinct  layers, 
although  they  have  not  been  so  closely  sized  as  would  have 


570  ORE  AND  STONE-MINING. 

been  requisite  if  the  separation  had  depended  upon  equivalence 
alone. 

In  a  few  exceptional  cases  the  valuable  mineral  rises,  as  it  is 
lighter  than  water ;  when  a  mixture  of  ozokerite  and  clay  is 
thrown  into  water,  the  waste  falls  to  the  bottom  whilst  the 
useful  substance  floats  and  may  be  skimmed  off  at  the  top. 
Bitumen,  too,  comes  to  the  surface  when  bituminous  sandstone  is 
thrown  into  boiling  water  and  stirred. 

Croll's  process  for  extracting  sulphur  from  rock  containing  the 
element  in  the  native  state,  now  abandoned  on  account  of 
practical  difficulties,  is  another  instance  of  a  separation  by  buoy- 
ancy. A  solution  of  chloride  of  calcium  was  prepared  strong 
enough  to  have  a  specific  gravity  decidedly  above  2  ;  when  the 
rock  was  plunged  into  a  hot  solution  of  this  kind,  the  sulphur 
gradually  liquefied,  oozed  out  and  rose  to  the  top,  leaving  the 
heavier  matrix  at  the  bottom. 

A  second  method  of  utilising  the  fall  in  water  consists  in 
subjecting  the  particles  to  a  current  flowing  upwards ;  by  suitably 
regulating  its  force,  light  particles  can  be  carried  away  and  only 
the  heavier  allowed  to  sink. 

Lastly,  a  third  kind  of  motion  is  that  of  small  particles  car- 
ried down  inclined  planes  by  a  thin  sheet  of  water. 

We  have  now  to  consider  the  various  machines  by  which  the 
fall  in  water  is  made  to  effect  a  separation  on  a  commercial  scale. 

1.  Simple  Fall  in  Water, 

Keeve  or  Dolly-tub. — This  appliance  is  merely  a  vat  or  tub 
in  which  the  finely  divided  ore  is  stirred  and  then  allowed  to 
settle ;  it  is  specially  used  for  the  final  treatment  of  fine  lead  ore 
and  tin  ore.  The  stirring  may  be  done  with  a  shovel  whilst 
the  ore  is  thrown  into  the  water,  but  more  commonly  blades, 
attached  to  a  vertical  axle  driven  by  gearing  (Figures  644  and 
645),*  are  made  to  keep  the  mixture  of  ore  and  water  in  a 
thorough  state  of  agitation.  When  enough  ore  has  been  added, 
the  stirring  process  (tossing)  is  stopped  and  the  agitator 
removed ;  the  contents  of  the  vat  are  allowed  to  settle,  while 
the  water  is  kept  in  a  state  of  vibration  by  taps  upon  the  outside 
from  the  iron  hammer  6,  lifted  by  the  cams  c,  upon  the  driving 
shaft.  This  process  of  settling  is  locally  called  packing;  as  soon  as 
it  is  complete,  the  water  is  baled  out  or  drawn  off  by  removing 
plugs  in  the  side,  and  the  deposit  is  scraped  off  layer  after  layer, 
increasing  in  richness  as  the  bottom  is  approached. 

Jigger  or  Jig. — The  principal  machine  for  concentrating 
particles  varying  in  size  from  i  inch  to  -fa  inch  is  the  jigger. 
The  hand-jigger  is  merely  a  round  sieve  which  is  charged  with 
the  crushed  ore  and  then  moved  up  and  down  in  a  tub  full  of 

*  Teague,  "  On  Dressing  Tin  Ore,"  Proc.  Min.  Inst.  Cornwall,  vol.  i. 


DRESSING.  571 

water.  Each  time  that  the  sieve  is  lowered  sharply  into  the 
water,  the  particles  are  free  to  drop  a  short  distance,  and  they 
gradually  arrange  themselves  in  layers,  the  heaviest  at  the  bottom 


FIG.  644. 


FIG.  645. 


FIG.  646. 


and  the  lightest  at  the  top.  On  lifting  out  the  sieve  the  light 
waste  can  be  skimmed  off  with  a  scraper,  leaving  a  well-defined 
layer  of  the  heavy  rich  mineral  at  the  bottom,  which  is  removed 
separately. 

This  process  of  separation  can  be  watched  by  the  aid  of  a  very 
simple  piece  of  apparatus  which  the  stu- 
dent can  construct  for  himself  (Fig.  646). 
A  model  jigging-sieve  can  be  made  with 
a  cylindrical  lamp-glass  by  fixing  on  a 
piece  of  wire  gauze  by  means  of  sealing- 
wax,  or  by  tying  on  a  piece  of  any  net-like 
fabric.  A  mixture  of  crushed  coal,  calc- 
spar,  and  galena,  prepared  as  in  the  pre- 
vious case,  is  placed  upon  the  sieve,  and 
the  glass  cylinder  is  now  moved  down 
and  up  in  a  large  tumbler  partly  filled 
with  water.  A  distinct  separation  is  soon 
effected. 

Instead  of  moving  the  sieve  in  still 
water,  it  is  more  common  nowadays  to 
make  the  sieve  stationary  and  to  force 
water  up  through  it  with  a  pulsating  action.  The  particles  are  thus 
subjected  to  a  series  of  repeated  lifts  and  falls,  and  after  the  lapse 
of  a  little  time  the  charge  of  crushed  ore  placed  upon  the  sieve 
becomes  separated  into  a  layer  of  rich  mineral  at  the  bottom,  and 
a  layer  of  light  waste  at  the  top  ;  in  the  middle  there  may  be  a 


572 


ORE  AND  STONE-MINING. 


layer  consisting  of  rich  particles  with  more  or  less  waste  material 

attached  to  them. 

An  illustrative  model  is  again  easily  constructed  (Fig.  647)  by 

fixing  a  piece  of  wire  gauze  in  a  lamp-glass,  between  two  rings 

cut  from  india-rubber  hose  of  suitable  diameter,  whilst  a  flexible 

ball  syringe  supplies  the  means  of  pumping  water  up  and  down. 
However,  this  is  not  the  form  in  which  the  jigger 

FIG.  647.  ig  made  in  actual  practice.  It  usually  consists  of  a 
box  (hutch)  divided  by  a  partial  partition  into  two 
compartments  ;  in  one  is  fixed  a  flat  sieve  s  (Figs.  648 
and  649),  which  carries  the  ore,  and  in  the  other  a 
piston,  p,  is  made  to  work  up  and  down  by  an  ex- 
centric.  The  mode  in  which  the  separation  is  effected 
can  be  watched  in  a  model  made  out  of  a  U-tube, 
with  a  round  stick  or  a  test-tube  as  the  piston 
(Fig.  650). 

The  great  advantage  of  these  jiggers  is  that  they 
readily  allow  a  continuous  feed  of  the  ore  and  dis- 
charge of  the  products  without  any  stoppages.  The 
ore  is  fed  on  by  a  hopper  placed  at  one  end  of  the 
machine,  or  is  delivered  already  mixed  with  water. 
Several  methods  of  discharge  can  be  adopted :  viz., 
(a)  at  the  end ;  (b)  in  the  centre ;  and  (c)  through 
the  meshes  of  the  sieve. 

(a)  With  the  first  kind  of  discharge,  the  enriched 
product  lying  on  the  sieve  passes  out  through  open- 
ings at  the  end  of  the  jigger,  and  the  amount  escaping 
is  regulated  by  an  adjustable  shutter  which  enables 
the  size  of  the  outlets  to  be  increased  or  diminished  at 
pleasure ;  the  middle  product  can  be  drawn  off  by  open- 
ings placed  at  a  slightly  higher  level,  whilst  the  waste 

is  washed  over  a  sill  at  the  end  of  the  sieve  at  each  pulsation. 

Very  often  a  first  sieve  simply  separates  a  concentrated  product 

and  discharges  a  poorer  product  on  to  a  second  sieve  where  a 

similar  separation  is  effected. 

(b)  With  the  central  discharge  method,  a  pipe  is  brought  up 
through  the  middle  of  the  sieve,  and  the  size  of  the  opening  for 
the  escape  of  the  concentrated  ore  is  governed  by  a  cylindrical 
cap,  which  can  be  raised  or  lowered  by  a  screw. 

(c)  The  discharge  through  the  sieve  is  specially  adapted  for  the 
finer  products  from  the  crusher,  though  it  is  also  used  for  grains 
up  to  and  even  above  \  in.  in  diameter.     The  mesh  of  the  sieve  is 
chosen   so    that   the  particles  under   treatment    will   just    pass 
through,  but  above  the  sieve  is  a  layer  (bed)  of  clean  ore,  or  of 
some  substance  of  about  the  same  density,  in  fragments  too  large 
to  drop  through.     The  pulsations  of  the  water  cause  the  usual 
separation  into  layers,  and  the  heavy  rich  particles  find  their  way 
down   through  the  bed  of  mineral  of  like  specific  gravity  and 


DRESSING. 


573 


drop  into  the  hutch,  whence  they  can  be  drawn  off  through  a 
hole  as  required.     The  poorer  part  passes  over  a  sill  at  the  end 


FIG.  649. 


FIG.  650. 


of  the  sieve,  as  a  worthless  product,  or  on  to  a  second  sieve,  so 

that  more  valuable  mineral  may  be  taken  out  of  it.     Three  or 

four  sieves  are  often  arranged  in  a  row  in  one 

machine,   and,    by  proper   arrangement    in 

dressing  mixed  lead  and  zinc  ores,  the  first 

compartment  may   be  made  to  yield   clean 

galena,  the  second  a  mixture  of  galena  and 

blende,  the   third  clean  blende,  the  fourth 

mixed  blende  and  rock,  whilst  the  greater  part 

of  the  waste  material  passes  over  the  sill  at  the 

end.  These  jiggers,  with  the  discharge  through 

the  sieve,  are  commonly  known  as  Hartz  jigs. 

The  number  of  strokes  per  minute,  the 
length  of  stroke  and  the  thickness  of  bed 
depend  upon  the  fineness  of  the  particles 
under  treatment ;  the  former  gradually  in- 
creases, while  the  two  latter  decrease  as  the 
particles  diminish  in  size. 

The  piston  of  the  jigger  need  not  neces- 
sarily be  horizontal.  Messrs.  Kitto  and  Paul 
place  it  vertically  in  the  jiggers  employed  at 
Frongoch  mine,  Cardiganshire,  for  treating  blende  and  galena. 
A  and  B  (Fig.  651)  are  the  two  hutches,  and  C  is  a  partition 
in  the  middle.  D  is  the  piston  working  between  two  plates  of 


574 


ORE  AND  STONE-MINING. 


iron  V  V.  The  piston  occupies  the  whole  length  of  the  jig, 
shown  by  T  (Fig.  652) ;  it  is  worked  by  the  rod  E,  guided 
at  F,  and  passing  through  a  stuffing-box,  G.  The  reciprocating 
motion  is  given  by  a  crank  M  through  the  connecting-rod  L  and 

FIG.  651. 


£ 


Scale 


Ifcfe, 


wM 

~6  feet 


lever  H,  which  traverses  the  head  of  the  piston-rod  I.  The  crank 
has  a  long  loop,  which  enables  the  stroke  to  be  varied.  The  same 
end  can  be  attained  by  an  excentric  with  a  slot,  which  allows  the 
excentricity  to  be  altered  at  pleasure.  N  shows  where  the  ore  is 
fed  on,  and  0  is  the  place  of  discharge  of  the  waste  or  impoverished 

FIG.  652. 


ore.  S  is  the  sieve,  and  P  P  are  holes  with  plugs  manipulated  by 
handles  not  shown  in  the  figures,  by  which  the  concentrates 
which  pass  through  the  sieve  are  drawn  off.  It  is  the  pipe  bring- 
ing in  clean  water. 

2.  Upward-current  Separators. 

We  must  now  pass  on  to  the  second  method  of  utilising  the 
motion  of  minerals  in  water,  viz.,  by  subjecting  them  to  an 
upward  current;  and  here  it  may  be  remarked  that  the  con- 


DRESSING. 


575 


tinuous  jig  to  a  certain  extent  produces  an  action  of  this 
kind,  for  the  light  waste,  brought  to  the  top  by  the  pulsating 
movement,  is  finally  carried  away  by  the  outflow  of  the  fresh 
water. 

Upward-current  separators  are  usually  inverted  pyramidal  or 
conical  boxes  with  water  under  pressure  brought  in  near  the 
bottom.  A  stream  of  ore  and  water  is  fed  in  at  the  top, 
some  of  the  heavier  particles  sink  and  make  their  escape  with  a 
portion  of  the  water,  at  or  near  the  bottom,  whilst  the  lighter 
grains  are  carried  over  the  edge  of  the  box.  A  separator  of  this 

FIGS.  653  and  654. 


SCALE 


M.I  0-5 


I2INS         0123456703  FEET 


kind  simply  extracts  a  number  of  like-falling  particles,  and 
the  product  may  require  further  treatment  before  a  sufficient 
degree  of  concentration  is  obtained. 

Jacome'ty  and  Lenicque's  Separators. — Figures  653  and 
654  represent  Jacomety  and  Lenicque's  pyramidal  separator  with 
six  compartments,  A,  B,  C,  D,  E,  F,  which  make  seven  cate- 
gories from  pulp  with  all  its  particles  under  i  mm.  in  diameter. 
Each  compartment  is  merely  a  box  in  the  form  of  an  inverted 
pyramid,  and  for  convenience  of  transport,  the  machine  is  made 
in  three  separate  castings,  which  can  be  easily  bolted  together, 
as  shown  at  R  and  S.  Pipes  bring  down  water  from  the  main 
G  H,  and  the  amount  supplied  to  each  division  can  be  regulated 
by  a  cock ;  the  water  strikes  a  little  plate  attached  to  the  end 
of  the  pipe  and  rises  up. 


•o 


576 


ORE  AND  STONE-MINING. 


The  pulp  is  fed  on  at  J  and  escapes  at  K.  Particles  which  can 
overcome  the  upward  current  are  discharged  continuously  through 
a  nozzle  at  the  apex  of  each  pyramid.  These  nozzles  are  shown 
at  L,  M,  N,  0,  P,  Q  ;  they  are  easily  detachable,  and  can  be  taken 

FIG.  655. 


twith  handle 


4  Feat 


off  during  the   progress  of  the   work,    if   by  any  chance   they 
become  choked. 

Though  separators  of  this  kind  are  usually  employed  for  the 
treatment  of  fine  sand  and  slime,  they  are  occasionally  applied  to 
comparatively  coarse  stuff.  The  separator  shown  in  Figures  655 
and  656  is  used  at  Frongoch  mine,  Cardiganshire,  for  treating 
an  ore  consisting  of  blende  and  galena,  mixed  with  slate,  just  as  it 
leaves  the  rolls,  after  having  been  crushed  fine  enough  to  pass 


DRESSING.  577 

through  a  sieve  with  12  holes  per  square  inch  (3  holes  by  4  holes). 
The  coarse  goes  to  the  jigs,  the  fine  to  the  buddies.  It  is  an 
inverted  wooden  cone  A,  which  can  be  more  or  less  com- 
pletely closed  at  the  bottom  by  a  plug  B,  controlled  by  a  handle 
C.  The  cone  stands  upon  a  wooden  box  D,  which  receives 
water  under  pressure  from  a  pipe  E,  and  is  provided  with 
a  discharge  valve  F,  a  mere  flat  plate  of  iron,  working  on  a 
pin,  which  can  be  pushed  sideways  so  as  to  close  the  orifice 
partially  or  entirely.  Inside  the  wooden  cone  there  is  a  sheet- 
iron  funnel  G,  which  receives  the  stream  of  ore  and  water 
from  a  launder  H,  and  causes  it  to  descend  to  the  level  I. 
There  it  meets  with  the  upward  current  of  clean  water,  and  a 
separation  is  effected.  The  coarse  and  heavy  particles  which  can 
overcome  the  stream  pass  into  the  box  below,  and  flow  out  con- 
tinuously at  F,  while  the  fine  and  light  particles  are  mastered  by 
the  current  and  carried  over  the  top  edge  of  the  wooden  cone, 
which  is  surrounded  by  a  circular  launder.  By  regulating  the 
upward  current  of  clean  water  and  the  size  of  the  discharge 
orifice,  the  separator  can  be  adjusted  to  the  requirements  of  any 
particular  case. 

Lockhart's  Automatic  Gem  Separator. — In  this  machine 
the  particles  of  minerals  fall  into  a  current  of  water  ascending  in 
an  annular  space,  purposely  made  narrow  in  order  to  prevent 
eddies,  which  would  interfere  with  the  desired  results.  The 
velocity  of  the  current  can  be  regulated  by  stop-cocks,  and 
arranged  so  that  only  the  denser  of  any  like-sized  particles  shall 
be  able  to  overcome  it  and  sink.  Its  primary  object  is  to  treat 
clean-washed  concentrates  from  gem-bearing  gravel  after  a  careful 
preliminary  sizing  by  screens. 

Siphon  Separator. — A  most  successful  application  of  an 
upward  current  of  water  is  in  the  machine  known  as  the  siphon 
separator,  though  its  action  is  not  based  upon  the  principle  of  the 
appliance  from  which  it  takes  its  name. 

It  consists  of  a  rectangular  box  (Figs.  657,  658,  and  659),* 
made  of  sheet  iron  or  wood  with  a  partition,  dividing  it  into  two 
chambers  B  and  E.  The  front  one  B  resembles  a  pyramidal 
separator,  receiving  an  upward  current  of  fresh  water  from  the 
adjacent  compartment  E  and  an  orey  stream  from  the  launder 
Gj  the  continuation  of  which  carries  away  the  light  waste.  The 
compartment  E  has  a  partition  z,  dividing  it  into  two  parts  :  A, 
which  receives  a  supply  of  fresh  water  by  means  of  the  pipe  a, 
and  C,  which  has  the  regulating  float  s.  To  prevent  shocks  and 
eddies,  the  water  does  not  fall  directly  into  E,  but  first  passes 
through  holes  in  the  partition  u.  The  precise  position  of  the 
float  s  can  be  altered  at  pleasure  by  the  rod  /,  which  connects  it 
to  the  lever  h,  movable  about  the  fulcrum  i  attached  to  the 

*  Heberwasche  des  Mechernicher  Bergwerks-Actien-Vereins,  B.  «.  h.  Z. , 
1886,  p.  476. 

2  O 


578 


ORE  AND  STONE-MINING. 


upright  bar  t.  The  travel  of  the  lever  is  controlled  by  means  of 
the  rod  g.  A  light  rod  e  carrying  the  outlet  valve  is  attached 
to  the  lever  at  d ;  this  valve  is  set  in  the  middle  of  a  pyramidal 
sieve  bottom  b,  and  governs  the  discharge  into  the  pipe  q,  which 


FIG.  657 


FIG.  658. 


leads  to  the  outlet  orifice  r.  The  object  of  these  arrangements  is 
to  obtain  a  self-regulating  discharge,  the  action  of  which  is 
very  simple.  As  the  ore-bearing  stream  passes  along  over  the 
box  £,  the  heaviest  particles  overcome  the  upward  pressure 
of  the  ascending  current  and  drop ;  if  the  valve  is  shut,  they 


DRESSING.  579 

accumulate  upon  the  sieve,  and  prevent  the  passage  of  some  of 
the  water  through  it.  The  obstruction  causes  the  water  in  the 
chamber  C  to  rise,  the  float  ascends  at  the  same  time,  and  in  so 
doing  lifts  up  the  valve  and  allows  the  discharge  of  the  grains 
of  ore  into  the  pipe  q.  The  float  then  sinks,  the  valve  goes  down, 
another  little  deposit  of  ore  causes  an  obstruction  and  the  process 
is  repeated. 

These  separators  are  some  of  the  principal  machines  employed  at 
Mechernich  for  the  treatment  of  the  friable  lead-bearing  sandstone ; 
in  fact,  there  are  no  less  than  124  of  them  in  use.  They  are 
remarkable  for  their  simplicity  and  for  the  large  amount  of  stuff 
that  they  will  treat.  The  quantity  of  broken  sandstone  which 
can  be  successfully  passed  through  one  machine  per  hour  is  from 
270  to  300  cubic  feet  (8  to  9  cubic  metres).  Sometimes  two  or 
three  of  these  machines  are  placed  one  after  the  other,  the  second 
receiving  the  overflow  of  the  first,  and  the  third  the  overflow  of 
the  second. 

The  quantity  of  water  required  is  somewhat  large — viz.,  9900' 
gallons  (45  cubic  metres)  per  hour ;  but  at  Mechernich  it  is  used 
over  and  over  again,  after  the  fine  matter  in  suspension  has  been, 
allowed  to  settle. 


3.  Separation  by  Water  flowing  down  Planes. 

We  lastly  have  to  deal  with  the  third  manner  of  utilising  the 
motion  of  mineral  particles  in  water,  that  is  to  say,  allowing 
them  to  be  carried  down  inclined  surfaces  by  a  stream  of  water. 

Two  classes  of  appliances  are  used  :  those  in  which  the  deposit 
is  cleaned  off  as  soon  as  a  thin  layer  has  settled  down,  and  those 
in  which  the  deposit  is  allowed  to  go  on  forming  until  it  has 
attained  a  thickness  of  at  least  several  inches  or  a  foot. 

(i)  The  first  class  includes  various  kinds  of  plane  and  conical 
tables,  certain  percussion  tables,  and  the  travelling  belts. 

Plane  Tables. — Plane  tables,  often  called  "frames,"  and 
sometimes,  but  incorrectly,  called  "  buddies,"  are  slightly  inclined 
rectangular  surfaces  of  wood  down  which  the  pulp  flows  in  a 
regular  stream.  An  even  flow  over  the  whole  width  of  the  table 
is  secured  by  first  passing  the  stream  over  a  head-board,  which 
divides  it  into  a  number  of  little  rills.  The  strength  of  the 
current  depends  upon  the  quantity  of  water,  and  upon  the 
inclination  given  to  the  table.  These  are  arranged  so  that  some 
of  the  mineral  under  treatment  will  settle  down  and  resist  the 
action  of  the  water,  which  is  always  tending  to  carry  it  on 
further.  After  a  deposit  of  this  kind  is  formed,  clean  water  is 
often  allowed  to  run  down  over  the  table  to  carry  off  any  light 
particles  intermixed  with  the  heavy  ore,  and  its  action  is  aided 
by  brushing  lightly  with  a  broom.  The  deposit  is  then  washed, 
off  and  collected  in  a  tank  for  further  treatment. 


S8° 


ORE  AND  STONE-MINING. 


Where  the  mineral  to  be  treated  is  poor,  the  tables  have  to  be 
worked  with  as  small  an  expenditure  of  labour  as  possible ;  and 


FIG.  660. 


INS. 12 


to  FE:E:T 


DE.CIME.TRE.S  10 


2  METRE.S 


FIG.  66 1. 


SCALE. 


DtCIMETRLS 


the  device  adopted  in  Cornwall  is  explained  by  Figs.  660  to  662.* 
A  is  a  launder  bringing  the  pulp,  which  flows  down  over  the  head- 

*  Ferguson,  "  On  the  Mechanical  Appliances  usod  for  Dressing  Tin  and 
Copper  Ores  in  Cornwall,"  Proc.  Inst.  31.  E.,  1873,  p.  130. 


DRESSING.  581 

board  B  on  to  the  inclined  surface  of  the  table,  leaving  upon 
it,  in  virtue  of  their  high  specific  gravity,  some  of  the  heavy 
particles  of  tin  ore,  and  carrying  the  lighter  refuse  into  the 
launder  C.  While  this  action  is  proceeding,  the  clean  water 
launder  E  is  filling  the  two  V-like  troughs  D  and  D'.  When 
these  are  full,  they  tilt  over  (Fig.  662)  and  discharge  their  contents 
suddenly  on  to  the  table,  washing  off  the  deposit.  The  troughs 
D  and  D',  on  turning  over,  carry  the  bar  H  H  forwards,  and 
thus  lift  the  flaps  at  F  and  F',  so  that  the  upper  and  richer 
part  of  the  deposit  is  washed  into  the  launder  F,  the  lower  and 
poorer  part  into  F'.  As  soon  as  the  troughs  have  discharged 
their  water,  they  are  brought  back  into  their  original  position  by 
the  simple  cataract  G,  and  the  process  is  repeated. 

Round  tables  are  bluntly  conical,  convex  or  concave  surfaces ; 
with  the  former  the  pulp  is  fed  on  at  the  centre  and  runs  down  to 
the  circumference  ;  with  the  latter,  the  direction  of  flow  is  reversed. 
The  tables  are  made  of  wood,  planed  cast-iron,  or  cement ;  the 
wooden  tables  may  be  plain  or  covered  with  india-rubber.  They 
are  stationary  or  revolving. 

An  excellent  stationary  table  is  that  of  Linkenbach*  (Figs.  663 
and  664).  The  table  itself,  a,  is  made  of  masonry  with  a  smooth 
surface  of  cement ;  b  is  an  upright  shaft,  which  carries  the  pulp-dis- 
tributor and  the  pipes  supplying  water  for  cleaning  and  for  wash- 
ing off  the  deposit ;  it  is  set  in  motion  by  the  worm  d  and  wheel 
c.  Two  of  eight  radial  arms,  borne  by  a  centre-piece,  are  indicated 
by  e  e ;  they  carry  the  apron  g,  the  clean  water  pipes,  h,  h,  h,  the 
position  of  which  can  be  regulated  at  pleasure,  and  the  washing- 
off  pipe  i.  The  clean  water  is  brought  in  by  the  circular  box  &, 
rotating  with  the  arms  e,  and  supplied  from  the  pipe  I ;  the  pulp 
is  delivered  through  the  pipe  m,  which  passes  along  the  conduit  n 
under  the  table  into  the  inner  ring  o  of  the  adjustable  dis- 
tributor o.  The  distributor  is  constructed  so  as  to  deliver  pulp  at 
o"  and  clean  water  at  o'" ;  p  p  are  pipes  bringing  down  clean 
water  from  the  rotating  launder  k,  and  q',  q",  q"  are  three 
concentric  gutters,  by  which  the  various  products  are  led  away. 
The  innermost  gutter  takes  the  waste  "  tailings,"  the  middle  one 
the  mixed  product,  and  the  outer  gutter  the  clean  concentrate. 
The  two  latter  products  are  conducted  each  into  its  proper  channel 
by  the  apron  g,  which  is  made  of  sheet  zinc. 

The  mode  of  action  of  this  table  is  easily  understood.  The 
distributor  is  constantly  feeding  on  slime  by  the  part  of  its  circum- 
ference r  o  s  (Fig.  664) ;  a  deposit  forms  on  the  table,  whilst  the 
lighter  tailings  run  off  into  the  gutter  q',  which  is  freely  open  to 
them  in  the  absence  of  the  apron.  As  soon  as  the  feeding  part  of  the 
distributor  has  passed,  clean  water  begins  to  flow  down  over  the  de- 
posit from  the  trough  o'",  carrying  oft  the  middlings  into  the  gutter 

*  Linkenbach,  Die  Auflereitung  der  Erze,  Berlin,  1887,  p.  101,  and  plate 
xvi. 


582 


ORE  AND  STONE-MINING. 

FIG.  664. 


FiG,664. 


GROUND   PLAN 


SCALES 


FttT    ID 

1 L. 

DtCIMtTRL-o 


DRESSING.  583 

q",  and  having  its  action  aided  by  the  washing-off  jets  h.  There  now 
remains  on  the  table  nothing  but  a  clean  concentrate,  and  this  is 
washed  off  into  the  gutter  q"f  by  the  jets  i ;  r'  is  a  launder  carry- 
ing away  the  waste ;  r"  conducts  the  middlings  to  a  settling  pit 
A,  and  the  concentrate  escapes  by  a  similar  launder  r'"  into  B  ; 
z  is  a  wire  rope  for  driving  a  second  table. 

An  easy  way  of  realising  the  mode  of  action  of  this  table  is  to 
divide  it  mentally  into  three  portions — viz.,  the  sector  from  t  to  r, 
which  is  receiving  the  slime ;  the  sector  from  t  to  w,  from  which 
the  middlings  are  being  washed  off;  and  lastly,  the  sector  from  v 
to  w  with  the  clean  concentrate,  which  yields  to  the  jets  issuing 
from  i,  and  passes  over  the  apron  into  the  outer  gutter  q'". 

Where  the  amount  of  space  is  limited,  Linkenbach  places  three 
tables  on  the  same  central  shaft ;  but  the  economy  of  space  and  of 
original  first  cost  is  accompanied  by  less  easy  supervision. 

The  mode  of  action  of  round  tables  is  very  often  just  the 
reverse  of  what  has  been  described  ;  that  is  to  say,  the  table 
revolves  and  the  distributor  is  stationary.  Linkenbach  points 
out  that  a  revolving  table  is  necessarily  subject  to  vibrations, 
which  must  interfere  with  the  evenness  of  the  flow  down  the 
inclined  surface,  whilst  the  fixed  table  with  a  travelling  distributor 
is  free  from  influences  of  this  kind  and  is  likely  to  work  more 
regularly. 

Nevertheless,  in  spite  of  this  objection,  revolving  round  tables 
may  be  seen  doing  good  work.  The  table  represented  in  Figs.  665 
and  666  is  one  designed  by  MM.  Jacomety  and  Lenicque.  A  is 
the  head-board  or  distributor  which  feeds  the  table  B  with  a 
stream  of  the  fine  slime  ;  the  table  is  made  of  arms  of  T-iroii, 
radiating  out  from  a  cast-iron  centre-piece  C,  which  support  a 
light  covering  of  planks.  Over  this  is  stretched  sheet  india-rubber, 
which  forms  a  smooth  surface,  free  from  any  liability  to  warp 
and  get  out  of  shape.  The  table  is  set  in  motion  by  the  vertical 
shaft  D,  driven  by  the  wheel  G  and  worm  H.  L  L  are  various 
pipes  bringing  clean  water,  supported  by  rods  N  N,  and  capable 
of  being  placed  in  any  suitable  position.  M  M  are  pipes  which 
wash  off  the  deposit  from  the  table;  they  are  held  up  by 
standards  N'  N',  which  can  be  shifted  about  at  pleasure.  K  is  a 
circular  launder  round  the  table,  with  discharge  holes  t  t,  and 
movable  wooden  partitions  *,  s', «",  «'",  s""  ;  lastly,  the  pipe  O  sends 
out  jets  of  water  which  clean  off  everything  remaining  upon  the 
table.  If  the  table  is  supposed  to  be  moving  in  the  direction  of  the 
arrow,  it  is  evident  that  products  of  different  kinds  will  be  washed 
off  at  different  periods  of  the  revolution,  and  that  towards  the 
end  nothing  will  remain  on  the  table  but  the  heaviest  particles. 
By  suitably  arranging  the  amount  of  feed  and  the  position  of  the 
different  washing-pipes,  the  table  can  be  made  to  give  clean  ore, 
waste,  and  intermediate  products ;  the  latter  are  passed  over  the 
same  or  a  similar  machine  once  more. 


584  ORE  AND  STONE-MINING. 

The  table  is  16  feet  5  inches  (5  m.)  in  diameter,  with  a  useful 
working  surface  4  feet  n  inches  (1*50  m.)  long;  it  makes  one 
revolution  in  3^  minutes,  requiring  less  than  ^  h.-p.  to  work  it. 
The  quantity  of  water  used  is  about  26  gallons  (120  litres)  per 
minute,  and  the  table  will  treat  from  5  to  8  tons  of  slime  in  ten 
hours.  As  it  is  made  of  eight  segments  bolted  together,  it  is 
easily  transported  and  erected. 

FIGS.  665  and  666. 


Percussion  Tables. — Rittinger's  side-blow  percussion  table 
(Fig.  667)  is  an  inclined  rectangular  platform  suspended  by  the 
four  corners  A  B  C  D,  receiving  blows  and  bumps  on  the  side.  A 
stream  of  orey  water  S  is  fed  on  to  the  corner  A,  and  clean  water  W 
runs  down  from  other  head-boards  H  H  H.  By  means  of  cams  upon 
a  revolving  shaft,  the  table  is  pushed  out  in  the  direction  of  the 
arrow,  and  it  is  then  driven  back  by  a  spring,  so  that  the  cross-piece 
E  strikes  against  the  bumping-block  L.  The  light  particles  travel 
down  the  table  much  faster  than  the  heavy  ones,  and  taking  a 
comparatively  straight  course,  leave  the  table  at  K;  whereas 


DRESSING. 


585 


the  heavy  and  richer  particles  remain  on  the  table,  subject  to  the 
influence  of  the  side-blows,  for  a  much  longer  time,  and  travelling 
along  a  curved  path  reach  the  bottom  at  F.  An  intermediate 
product  is  discharged  at  G.  The  exact  degree  of  richness  or 
poorness  can  be  regulated  by  pointers,  strips  of  wood  which  can 
be  turned  so  as  to  divide  the  stream  of  ore  and  waste  where 
thought  most  desirable.  The  great  advantage  of  this  machine 
over  the  old  percussion  frame  is  its  continuous  action. 

Travelling  Belts. — We  now  come  to  the  travelling  belts,  of 
which   there  are  many  varieties.     An  early  form  was  that  of 
Brunton,*  an  endless  belt  of  canvas  acting  in  the  same  way  as 
FIG.  667. 

s       w 


FIG.  668. 


the  now  favourite  Frue-vanner,  save  that  there  was  no  shake 
sideways.  In  fact,  the  latter  machine  is  regarded  by  some  as  an 
improved  form  of  the  Brunt  on  cloth. 

The  Frue-vanner  (Fig.  668)  is  an  endless  band  of  india-rubber 
cloth,  4  feet  wide  and  27  feet  long,  with  an  upper  working  surface 
of  about  1 2  feet  in  length.  The  belt  is  supported  by  a  frame  with 
a  number  of  small  rollers  on  which  it  travels  easily,  and  it  is 
driven  slowly  in  the  direction  of  the  arrows  by  the  upper 
end  roller  shown  in  the  figure.  The  small  roller  by  the  side 
of  the  large  one,  which  dips  into  the  tank,  serves  for 
tightening  up  the  belt  when  required.  The  whole  frame 
carrying  the  belt  receives  a  motion  sideways  from  three  little 
cranks  upon  a  small  shaft  running  parallel  to  its  length.  The 
pulp  is  fed  on  by  the  head-board  A,  and  clean  water  by 
another  B.  The  natural  path  of  the  particles  is  down  the 
inclined  belt,  but  those  which  can  resist  the  action  of  the 

*  Sopwith,  "  The  Dressing  of  Lead  Ores,"  Proc.  List.  C.  E.,  vol.  xxx.,  1870, 
p.  112. 


586  ORE  AND  STONE-MINING. 

stream  of  clean  water  at  B,  go  over  the  top  end,  and  are  washed 
off  as  the  belt  passes  through  the  tank.  The  poor  stuff  is 
discharged  into  the  waste  launder  at  the  other  end.  The  degree 
of  concentration  can  be  regulated  by  the  slope  and  speed  of  the 
belt  and  the  strength  of  the  streams  of  ore  and  water.  The 
Frue-vanner  has  the  disadvantage  that  it  makes  only  two  classes, 
rich  and  poor,  without  any  intermediate  product. 

The  success  of  the  Frue-vanner  has  naturally  brought  a  number 
of  somewhat  similar  contrivances  into  the  market.  The  Embrey 
concentrator  may  be  likened  to  a  Frue-vanner,  with  a  longitudinal 
instead  of  a  lateral  shake. 

The  Woodbury  ore  concentrator  is  made  up  of  several  narrow 
belts  each  with  its  own  flanges,  instead  of  there  being  one  broad 
band.  The  object  of  this  arrangement  is  to  prevent  uneven- 
ness  of  flow,  for  if  strong,  irregular  currents  are  formed  in  the 
centre  of  the  belt,  they  may  carry  away  good  ore  into  the  waste 
launder. 

Stein's  endless  belt,  which  has  been  improved  by  Bilharz,  has  a 
totally  different  mode  of  action.  It  resembles  the  Rittinger 
percussion  table  in  its  manner  of  effecting  a  separation,,  but  the 
work  is  done  on  a  travelling  belt  instead  of  an  unchanging  sur- 
face. Stein's  machine  *  (Figs.  669,  670,  and  671)  is  a  rectangular 
frame  a,  suspended  between  two  posts  p,  by  rods  i,  at  the  four 
corners,  so  that  it  can  swing  in  the  direction  of  its  long  side.  The 
inclination  of  the  frame  can  be  altered  at  pleasure,  by  the  handle 
attached  to  the  cross-beam  I,  which  works  upon  the  screw  e,  but 
the  long  side  always  remains  horizontal.  The  frame  is  drawn  slightly 
out  of  position  by  cams  r,  acting  upon  the  lever  m,  and  as  soon  as 
it  is  released  it  is  pulled  back  against  a  bumping-piece  £,  by  a 
spring  n.  The  frame  has  two  large  rollers  c  c,  and  three  «mall  ones 
underneath,  which  carry  an  endless  belt  of  india-rubber/,  the  upper 
part  of  which  is  further  supported  by  the  flat  bed  of  boards  b. 
The  belt  slides  over  this  bed,  and  is  prevented  from  sticking  to  it 
by  a  constant  flow  of  water,  supplied  by  the  pipe  g,  along  narrow 
diagonal  grooves.  One  of  the  end  rollers  is  made  to  revolve  and 
carries  the  belt  with  it.  The  pulp  is  fed  on  by  a  head-board  k, 
and  clean  water  is  turned  on  through  holes  in  the  pipe  o.  The 
direction  of  travel  of  the  belt  is  indicated  by  the  arrow.  The 
concentrating  action  is  like  that  of  a  Rittinger  table.  The 
lightest  particles  run  down  at  once,  and  leaving  the  belt  at  the 
right-hand  end  of  the  table,  fall  into  the  first  compartment  of  the 
launder  g,  whilst  the  heaviest  remain  on  the  table  much  longer, 
and  are  finally  discharged  at  the  left-hand  end.  Intermediate 
products  run  off  in  the  middle. 

(2)  The   second   set  of   appliances  includes   the   buddies   and 
ordinary  percussion  tables. 

*  Blomeke,    "  Ueber  den  Stein'.schen  Plaimen-Stossherd,"  B.  u.  h.  Z., 
1891,  p.  69. 


DRESSING. 


587 


Buddies. — The  hand -bud  die  is  a  rectangular  wooden  box  with 
a  sloping  bottom.     A  stream  of  pulp  is  fed  in  by  a  head-board  at 


FIGS.  669  and  670. 


nfl      I 


FIG.  671 


the  upper  end  and  gradually  forms  a  deposit  on  the  floor  of  the 
bud  die.  A  boy  with  a  broom  keeps  the  surface  of  the  sediment 
even,  so  as^to  ensure  regularity  of  action.  After  a  thick  deposit 


588 


ORE  AND  STONE-MINING. 


has  accumulated,  it  is  dug  out  in  sections,  which  decrease  in  rich- 
ness from  the  upper  end  (head}  to  the  lower  end  (tail). 

Round  buddies  bear  the  same  relation  to  hand  buddies  that 
round  tables  do  to  hand  frames.  They  may  be  concave  or 
convex,  but  the  latter  are  the  more  common. 

The  convex  round  buddle  (Figs.  672  and  673)  is  a  circular  pit  * 
with  a  truncated  cone,  or  head,  of  varying  size  in  the  centre,  and  a 
bottom  sloping  towards  the  circumference.  The  orey  stream,  A, 

FIG.  672. 


FIG.  673. 


falling  over  this  head  runs  down  gently,  depositing  the  heaviest 
particles  near  the  top,  the  lighter  ones  further  down,  while  the 
lightest  of  all  flow  away  at  C.  The  surface  of  the  sediment  is 
kept  even  by  the  revolving  brushes  D.  This  machine  may  be 
compared  to  a  number  of  hand-buddies  arranged  radially  round 
a  centre.  The  deposit  which  is  formed  is  dug  out  in  rings  of 
varying  richness. 

The  concave  buddle  is  a  circular  pit  with  the  bottom  sloping 

*  Henry  T.  Ferguson,  "  On  the  Mechanical  Appliances  used  for  Dressing 
Tin  and  Copper  Ores  in  Cornwall/'  Proc.  Inst.  Mecli.  Eng.,  1873,  plate  xli., 
and  p.  124. 


DRESSING.  589 

towards  the  centre.  The  stream  of  ore  is  fed  all  round  the  cir- 
cumference, and  runs  inwards  towards  the  middle,  where  the 
lightest  particles  escape.  The  rich  head  is,  of  course,  near  the 
circumference. 

Ordinary  Percussion  Table. — The  ordinary  percussion  table, 
though  rarely  if  ever  seen  in  this  country,  is  still  employed  in 
Germany  and  regarded  with  favour.  Those  familiar  with  the 
hand-buddle  will  understand  what  it  is  like,  if  it  is  described  as  a 
swinging  hand-buddle  which  is  continually  being  bumped  at  the 
upper  end.  It  is  a  shallow  rectangular  sloping  wooden  or  iron 
tray  suspended  from  the  four  corners,  so  that  it  can  move  back- 
wards and  forwards  in  the  direction  of  its  length,  and  as  soon  as 
it  has  been  pushed  out  of  position  by  a  cam,  it  is  at  once  forced  back 
by  a  spring  against  a  fixed  wooden  bumping-block  at  the  upper 
end.  The  pulp  is  fed  on  at  the  upper  end  by  a  head-board, 
and  the  lightest  particles  run  off  at  the  lower  end,  which  has  no 
rim,  whilst  the  heavier  and  richer  ones  form  a  gradually  thickening 
layer  upon  the  bed.  When  sufficiently  thick,  the  deposit  is 
shovelled  off  in  sections  varying  in  richness  as  they  do  in  a 
buddle.  The  bump  assists  in  making  the  particles  settle,  just 
as  it  does  in  the  "  keeve,"  and  at  the  same  time,  in  virtue  of  the 
vis  viva  acquired  during  the  backward  stroke  of  the  table,  grains 
of  ore  are  constantly  being  thrown  up  a  little,  as  they  are  with 
the  German  hand- washing  dish. 

Machines  of  this  class  have  two  grave  defects :  careful  watching 
is  necessary,  in  order  to  keep  the  surface  of  the  deposit  perfectly 
even ;  otherwise  gutters  are  formed,  down  which  the  water  runs 
with  too  great  a  velocity,  carrying  away  rich  ore  or  depositing  it 
near  the  tail  end  when  it  ought  to  have  subsided  at  the  head. 
Secondly,  the  deposit  has  to  be  shovelled  off,  and  the  parts 
requiring  further  treatment  have  again  to  be  mixed  with  water 
and  brought  into  a  proper  consistency,  before  they  can  flow  on 
to  other  machines.  In  spite  of  these  drawbacks,  buddies  and 
percussion  tables  are  still  largely  employed. 

(2)  MOTION  IN  AIR. — In  countries  where  water  is  scarce, 
or  where  the  valuable  mineral  is  specially  liable  to  be  affected 
or  carried  off  by  water,  engineers  have  long  desired  to  employ 
air  as  the  medium  in  which  the  concentration  should  be  effected. 

Three  kinds  of  machines  are  used  :  the  pneumatic  jig,  the  fan, 
and  the  centrifugal  concentrator. 

l(heiimatic  Jig. — The  pneumatic  jig  resembles  the  hydraulic 
jig  in  principle ;  that  is  to  say,  particles  of  minerals  varying  in 
specific  gravity  can  be  separated  if  they  are  lifted  and  then 
allowed  to  fall  again,  provided  that  the  sizes  of  the  grains  do  not 
differ  too  widely,  and  that  the  specific  gravities  do  not  approach 
too  closely.  The  principle  will  be  most  easily  grasped  if  the 
student  constructs  a  very  simple  model  (Fig.  674).  A  piece  of 
glass  tube  with  the  upper  end  covered  by  net  or  muslin  is 


590 


ORE  AND  STONE  MINING. 


inserted  into  a  slightly  larger  tube.  The  lower  end  is  then 
connected  to  an  india-rubber  pump,  such  as  is  used  with  scent 
diffusers.  Pour  a  mixture  of  like-sized  grains  of  galena  and  sand 
on  to  the  sieve,  and  give  the  pump  a  succession  of  gentle  squeezes. 
Puffs  of  air  are  sent  up  through  the  sieve,  and  the  two 
FIG.  674.  minerals  arrange  themselves  as  shown,  the  galena  below, 
and  the  sand  above. 

By  using  a  bed  of  fine  shot,  jigging  through  the 
sieve  may  be  carried  out,  the  action  resembling  that  of 
the  Hartz  sand-jigs. 

Krom's*  pneumatic  jig,  which  is  in  actual  use  for 
treating  silver  ore,  is  a  wooden  chest  in  which  a  flat 
vane  moving  backwards  and  forwards  sends  a  number 
of  rapid  puffs  of  air  through  a  bed  of  fine  ore,  resting 
upon  a  sieve  made  of  short  upright  tubes  of  wire  cloth, 
with  small  spaces  between  them.  The  fine  ore  is  fed 
in  from  a  hopper  on  one  side  of  the  long  narrow  sieve. 
The  repeated  falls  bring  about  a  separation,  and  the 
light  waste  passes  over  the  edge  of  the  sieve  opposite 
to  the  feed-hopper,  whilst  the  concentrate  sinks  down 
through  the  interspaces  between  the  sieve  tubes  into 
a  reservoir,  from  which  it  is  drawn  off  gradually  by 
a  fluted  roller.  As  this  reservoir  is  always  kept  full, 
the  rate  of  discharge  and  degree  of  concentration  can 
be  varied  by  altering  the  speed  of  the  roller. 

Fans. — A  fan  is  used  in  connec- 
tion with  some  grinding  machines 
in  order  to  draw  off  the  powdered 
mineral,  and,  in  dealing  with  a 
homogeneous  substance,  the  amount 
of  suction  can  be  regulated  so  as  not 
to  draw  the  mineral  out  of  the 
machine  until  it  has  been  sufficiently 

pulverised.  If  the  dust-laden  air  is  then  discharged  into  a  large 
chamber,  the  coarsest  particles  will  settle  down  first,  whilst  the 
finest  will  be  wafted  to  the  far  end. 

As  an  instance  of  fan-action,  the  dressing  of  phosphate  of  lime 
may  be  mentioned.  Some  of  the  phosphate  of  lime  which  is. 
ground  between  millstones  in  France  is  not  passed  through  any 
sieve  at  all ;  a  fan  is  adjusted  so  as  to  draw  it  away  from  the  mill 
sufficiently  fine  to  be  put  into  sacks  at  once.  Tests  are  made 
from  time  to  time  to  see  that  the  product  is  properly  ground, 
for  it  is  sold  with  the  guarantee  that  not  more  than  a  certain 
percentage  shall  be  too  coarse  to  pass  through  a  given  sieve. 

Another  example  may  be  taken  from  some  of  the  fuller 's- 
earth  dressing  establishments.  The  earth  is  ground  in  an 

*  Gallon,  "  Lectures  on  Mining,"  Paris  and  London,  1886,  vol.  iii.,  p.  104 
and  Atlas,  plate  civ. 


DRESSING.  591 

Askhara  mill  and  forced  by  a  fan  into  a  chamber  some  50  feet 
long  by  10  feet  wide,  where  it  drops  upon  the  ground ;  the  deposit 
is  shovelled  away  afterwards  in  sections,  which  are  finer  and  finer 
as  one  goes  away  from  the  orifice  through  which  the  dust  enters. 
The  requirements  of  different  customers  can  thus  be  satisfied. 

When  a  fan  is  employed  for  drawing  off  the  fine  product  from 
a  mill  or  crusher,  it  likewise  serves  the  useful  purpose  of  pre- 
venting the  atmosphere  of  the  works  from  being  polluted  by 
noxious  dust. 

Centrifugal  Concentrator. — These  concentrators  are  based 
upon  the  fact  that  when  bodies  of  equal  volume  are  whirled  round, 
the  centrifugal  force  developed  is  proportional  to  their  densities. 
Therefore,  if  the  like-sized  particles  are  projected  by  centrifugal 
force  from  a  machine,  the  denser  ones,  with  their  larger  store  of 
energy,  will  be  better  able  to  overcome  the  resistance  of  the  air 
than  those  which  are  specifically  lighter,  and  will  consequently 
travel  further.  The  truth  of  this  can  be  made  manifest  with  a 
child's  top.  Spin  the  top  in  a  saucer  or  dish  raised  a  little  above 
the  table,  previously  covered  with  a  sheet  of  paper  or  cardboard, 
and  feed  on  to  its  flat  upper  surface  a  thin  stream  of  finely 
powdered  galena  and  sand,  which  has  passed  through  a  sieve  with 
100  holes  to  the  linear  inch  and  refused  to  pass  the  120  mesh. 
The  particles  will  be  whirled  off,  light  sand  will  drop  close  to 
the  saucer  or  even  into  it,  whilst  the  heavy  galena  picks  up  a 
larger  amount  of  energy  from  the  spinning-top  and  flies  further 
away  before  settling.  By  brushing 
up  the  dust  concentrically,  the  FlG> 

effect  will  be  apparent. 

The  Clarkson-Stanfield  concen- 
trator (Fig.  675)  works  precisely  in 
this  way.  B  is  a  distributor,  which  is 
made  to  revolve  rapidly  by  its  spindle 
0.  The  hopper  A  supplies  it  with 
finely  powdered  and  carefully  sized 
ore,  which  escapes  by  a  number  of  radial  holes.  The  dotted  lines 
show  the  paths  taken  by  the  particles  of  mineral,  which  drop  into 
a  series  of  concentric  troughs  from  which  they  can  be  swept  by 
revolving  brushes  into  discharge-spouts. 

In  order  to  work  successfully,  the  ore  must  be  very  carefully 
separated  by  screening  into  particles  of  approximately  the  same 
volume.  The  machine  is  new,  and  has  yet  to  bear  the  test  of 
actual  practice  on  a  large  scale  at  mines,  but  it  is  worth  noting 
that  a  similar  appliance  is  used  at  mills  *  for  freeing  semolina 
from  bran  and  dust.  The  Pape-Henneberg  f  ore  concentrator  is 
identical  in  principle  with  that  of  Clarkson  and  Stanfield. 

A  disadvantage  of  all  pneumatic  dressing  is  that  the  ore  has  to 
*  Spon's  Dictionary  of  Engineering,  London,  1873,  vol.  vii.,  p.  2499. 
t  B.  u.  h.  Z.,  1893,  p.  IQI. 


592  ORE  AND  STONE-MINING. 

be  very  thoroughly  dried,  for  otherwise  the  particles  stick  together 
slightly  and  counteract  the  action  of  the  forces  which  should  effect 
the  desired  separation. 

(3)  DESICCATION. — Various  reasons  call  for  the  drying  of 
minerals.  Sometimes  the  mineral  cannot  be  ground  until  it  is 
freed  from  moisture ;  in  other  cases  drying  is  advisable  in  order  to 
save  the  payment  of  carriage  upon  a  useless  ingredient ;  it  is  like- 
wise necessary  before  a  mineral  is  roasted  in  furnaces,  or  passed 
through  certain  magnetic  separators,  and,  as  has  just  been 
remarked,  it  is  indispensable  when  the  subsequent  treatment  is 
effected  by  a  pneumatic  process. 

Drying  may  be  carried  on  in  one  of  the  following  ways  : 

a.  By  exposure  to  the  air. 
6.  By  open  fires. 

c.  On  open  floors  or  pans. 

d.  In  enclosed  stoves  or  kilns. 

e.  By  filter  presses. 

a.  Air  Drying. — Simple  exposure  to  the  action  of  the 
atmosphere,  under  a  light  roof  as  a  protection  from  occasional 
showers,  is  quite  sufficient  for  the  purpose  of  drying  many 
minerals,  provided  that  the  weather  is  fine.  China  clay  and 
ochre  are  sometimes  dried  in  this  way.  The  roughly  cubical  clods 
are  piled  up  one  above  the  other,  allowing  free  access  of  air,  and. 
if  the  weather  is  favourable,  a  sufficient  amount  of  moisture 
evaporates  naturally  to  render  the  mineral  fit  for  the  market ; 
but  a  wet  season  sadly  interferes  with  the  work,  frost  will  cause 
the  clods  to  crumble,  and  artificial  drying  often  becomes  necessary 
in  order  to  satisfy  the  demands  of  customers. 

In  Chili  the  crystals  of  nitrate  of  soda  are  soon  dried  perfectly 
by  exposure  to  the  atmosphere. 

6.  Open  -  fire  Drying.  —  The  phosphate  of  lime  dug  or 
dredged  in  South  Carolina  is  sometimes  dried  by  heaping  it  upon 
piles  of  wood  which  are  set  alight. 

c.  Drying  on  Heated  Open  Floors. — Heated  floors  are  em- 
ployed in  drying  barytes,  fuller's  earth,  and  phosphates  previous 
to  grinding,  other  minerals  previous  to  roasting,  and  china  clay 
previous  to  sale. 

Fig.  676  shows  a  Cornish  "  dry"  for  china  clay.*  The  letters  I  I 
represent  the  "  settling  tanks"  or  stone-lined  pits  into  which  the 
clay  is  run,  in  the  form  of  a  thin  mud,  after  the  coarsest  particles 
of  the  decomposed  granite  have  been  separated.  Here  it  forms 
a  sediment  of  the  consistency  of  thick  cream,  which  is  trammed 
to  the  "  dry,"  after  the  water  has  been  drawn  off.  The  drying- 
house  is  composed  of  the  dry  proper  m  m,  and  the  storing  sheds 
or  "  linhays,"  o  o.  The  floor  of  the  dry  is  made  of  large  fire-clay 
tiles,  which  cover  a  number  of  flues,  each  about  14  inches  wide, 

*  Collins,  "  The  Hensbarrow  Granite  District,"  Truro,  1878,  p.  20. 


DRESSING. 


593 


leading  away  from  the  fireplaces,  s  8.  The  tiles  are  5  or  6  inches 
thick  over  the  fires,  where  the  heat  is  greatest,  and  the  thickness 
is  reduced  to  2  J  or  2  inches  at  the  other  end  of  the  building.  The 
clay  is  trammed  in  along  the  road  1 1,  and  tipped  on  to  the  floor  or 
"  pan  "  m  m,  until  it  forms  a  layer  9  inches  thick  at  the  fire-end 
and  6  inches  thick  at  the  stack-end.  The  clay  at  the  fire-end 
is  dried  in  24  hours ;  it  is  cleared  off  and  stored  in  the  linhay 
o  o,  and  another  charge  of  wet  clay  trammed  in ;  the  further 
the  clay  is  from  the  fire,  the  longer  it  takes  to  dry,  and  at  the 
stack-end,  the  "  pan "  can  be  cleared  and  re-loaded  only  twice 
or  three  times  a  week.  It  appears  that  much  more  of  the 

FIG.  676. 


moisture  soaks  down  through  the  tiles  and  is  carried  away  as 
steam  by  the  flues,  than  evaporates  from  the  surface  of  the  pan, 
and  for  this  reason  the  tiles  are  made  as  porous  as  possible. 

The  open  floors  used  for  drying  phosphate  of  lime  in  the 
North  of  France  previous  to  grinding  have  the  bed  made  of 
sheets  of  iron.  The  plates  are  about  one  metre  square  and 
are  laid  upon  a  series  of  parallel  flues  formed  of  little  walls  one 
brick  thick.  The  floors  are  often  about  20  metres  long  and  4 
metres  wide.  In  order  to  accelerate  the  process  of  drying  the 
sandy  phosphate  is  shovelled  over  from  time  to  time  by  men,  but 
the  cost  of  labour  can  be  reduced  by  using  Arnett's  mechanical 
hoe  which  performs  the  same  office.  It  is  a  frame  stretch- 
ing across  the  whole  width  of  the  floor,  carrying  a  single 
row  of  broad  blades  or  spades,  which  can  be  inclined  at  any 

2  P 


594  ORE  AND  STONE-MINING. 

desired  angle  to  the  bed;  it  is  drawn  backwards  and  for- 
wards by  machinery.  The  blades  pass  into  the  layer  of  phosphate 
on  the  floor,  heap  up  the  stuff  in  front  of  them,  and  cause  the 
particles  to  mount  up,  and  then  fall  over  on  to  the  bed  again. 
Each  time  the  hoe  passes  along,  the  stuff  is  shifted  forwards  a 
little,  so  that  when  the  frame  arrives  at  the  end  of  its  course,  it 
pushes  off  a  portion  of  the  charge,  which  is  now  dry  enough  for 
milling,  as  it  has  travelled  along  the  full  length  of  the  bed.  As 
the  inclination  of  the  blades  can  be  altered,  the  rate  at  which  the 
stuff  is  carried  forwards  can  be  regulated  so  as  to  prolong  or 
shorten  the  drying  process,  as  required.  The  machine  is  made 
to  reverse  its  direction  of  travel  automatically,  but  it  does  no 
stirring  on  the  return  stroke. 

Thelen's  drier  is  an  open  semi-cylindrical  iron  pan  heated  by  a 
fire  below,  in  which  the  charge  is  stirred  by  knives  moved  me- 
chanically. 

d.  Stoves  and  Kilns. — The  number  of  kinds  of  enclosed  stoves 
and  kilns  employed  for  drying  minerals  is  very  great ;  and  it  is 
especially  in  the  case  of  brown  coal*  that  the  ingenuity  of  in- 
ventors has  been  exercised  to  devise  means  of  getting  rid  of 
moisture.  However,  as  the  subject  of  brown  coal  does  not  belong 
to  this  work,  the  special  stoves  made  use  of  cannot  be  dealt  with 
at  length  ;  still  it  is  right  that  they  should  be  mentioned,  as  some 
of  them  could  be  used  for  other  minerals. 

With  such  a  large  number  of  drying  stoves,  it  is  absolutely 
necessary  that  there  should  be  a  classification  of  some  kind,  for 
otherwise  the  student  runs  the  risk  of  being  confused. 

It  is  perhaps  most  convenient  to  classify  them  first  of  all  accord- 
ing to  the  mode  of  heating,  and  then  make  a  further  subdivision 
according  as  kiln  or  furnace  is  stationary  or  revolving. 

Enclosed  Kilns  and  Stoves. 

Mode  of  Heating.  Kind  of  Drying  Surface.  Name  of  Drying  Stove. 

{American      Phosphate 
kiln.     Fullers'  earth 
kiln 
Krom's  stove. 
Riebeck's  stove. 

(Revolving      .         Brunton's  furnace. 
Direct  fire  and  hot  air    ...  „ 

Hot  air  ...          Stationary 

0 ,  f  Stationary 

Steam  -         (Revolving 

Hot  air  and  steam  ...  Stationary 

American  Phosphate  Kiln. — The  kilns  employed  for  drying 
phosphate  of  lime  in  South  Carolina  f  after  washing  are  simply 

*  Vollert,  Der  Braunkohleriberglau  im  Oberbergamts-BezirJc  Halle  und  in 
den  angrenzenden  Staaten,  Halle  a.  d.  S.  1889,  p.  249. 

t  Benedict,  "Mining,  Washing,  and  Calcining  South  Carolina  Land 
Phosphate,"  Eng.  Min.  Jour.,  vol.  liii.,  1892,  p.  349, 


Ruelle's  stove. 
Rowoldt's  stove. 
Steam  stove. 
Schulz's  stove. 
Jacobi's  stove. 


DRESSING. 


595 


rectangular  chambers,  built  of  brick  and  roofed  with  wood.  The 
whole  of  the  bottom  is  covered  with  a  pile  of  wood,  on  to  which 
the  wet  phosphate  is  tipped  from  barrows.  The  wood  is  set  alight 
and  flues  supply  it  with  air  for  combustion.  Each  kiln  holds 
from  1000  to  1200  tons  of  phosphate ;  the  fire  burns  out  in  from 
two  to  five  days,  and  the  phosphate  is  then  ready  for  export. 

Fullers'  Earth  Kiln. — The  fullers'  earth  kiln  may  be  taken 
as  another  example  of  the  first  class.  It  is  a  brick  or  stone  build- 
ing about  36  feet  long  and  15  feet  wide,  with  an  arched  roof  of 
brick  (Fig.  677)  or  a  sloping  roof  of  slate.  About  9  feet  above  the 
bottom  is  a  floor  a,  made  of  cast- 
iron  plates  full  of  holes  about  J 
inch  in  diameter,  underneath 
which  are  two  sets  of  sloping 
shelves,  made  of  sheets  of  iron,  b  6, 
c  c,  which  can  be  taken  out  at 
pleasure  ;  d  is  a  deep  flue  bringing 
in  air  from  the  outside,  and  having 
two  openings  into  the  kiln,  covered 
with  fire-bars,  upon  each  of  which 
a  coke  fire,  e,  is  maintained.  A 
sheet  of  corrugated  iron,/,  is  hung 
up  over  each  fire,  in  order  to  pre- 
vent the  clay  immediately  above 
it  from  being  too  strongly  heated. 
Both  the  upper  and  lower  floors 
of  the  kiln  can  be  entered  by  large 
doors.  The  charging  is  all  done 
from  the  floor  a;  a  few  of  the 
plates  are  taken  up  on  each  side, 
the  sheets  b  b  removed,  and  clay 
is  wheeled  in  barrows  along  a  and  tipped  on  to  c.  The  plates  b 
are  replaced  and  similarly  covered  with  a  charge  of  clay,  and 
finally  a  receives  a  layer  of  damp  clay  6  or  8  inches  thick.  The 
doors  are  shut  and  the  fires  lighted ;  though  the  heat  is  con- 
siderable, it  is  not  enough  to  prevent  men  going  in  from  time  to 
time  to  put  on  more  fuel,  if  required.  The  moisture-laden  air 
ascends  and  escapes  through  the  roof  at  g. 

Krom's  Stove. — Krom's  stove  has  a  series  of  inclined  shelves, 
something  like  those  of  the  Hasenclever  furnace,  down  which  the 
mineral  gradually  makes  its  way  under  the  action  of  gravity, 
while  exposed  to  the  direct  action  of  the  hot  gases  coming  from 
a  fire.* 

Riebeck's  Stove. — Riebeck's  "Tellerofen"  consists,  as  its  Ger- 
man name  denotes,  of  a  number  of  superposed  circular  plate- 
like  shelves ;  a  central  revolving  shaft  carries  arms  with 

*  Sahlin,  "  Magnetic  Separation  of  Iron  Ore,"  Eng.  Min.  Jour.,  vol.  liii,, 
1892,  p.  638. 


SCALE    OF  FEET 
505 


SCALE.    OF  METRES 


I     OS    0 


596 


ORE  AND  STONE-MINING. 


teeth  or  knives  which  alternately 
cause  the  mineral  to  travel  out- 
wards and  inwards.  Thus  the 
mineral  fed  on  to  the  top  shelf, 
for  instance,  will  be  made  to 
travel  outwards  to  the  circumfer- 
ence, where  it  drops  through 
holes  on  to  shelf  No.  2  ;  here  the 
revolving  teeth,  arranged  in  the 
reverse  fashion,  draw  it  in  gradu- 
ally to  the  centre,  where  it  falls 
upon  shelf  No.  3,  and  it  goes  on 
travelling  backwards  and  for- 
wards in  this  fashion  until  it 
reaches  the  bottom  of  the  kiln. 
During  all  this  time  it  is  sub- 
jected to  the  action  of  the  hot 
gases  coming  from  a  fire  below. 

Brunton's  Furnace. — Though 
Brunton's  calciner  (Fig.  692)  was 
invented  for  the  purpose  of  roast- 
ing ores,  driers  have  been  con- 
structed upon  the  same  principle ; 
the  stove  is  a  circular  revolving 
horizontal  bed,  with  teeth  fixed 
above  it  which  cause  the  mineral, 
fed  in  at  the  centre,  to  travel 
gradually  to  the  circumference. 
A  fireplace  on  one  side  sends  the 
products  of  combustion  directly 
upon  the  mineral.  This  stove  is 
used  for  phosphate  of  lime,  be- 
sides being  employed  in  the 
.  manufacture  of  patent  fuel. 

Ruelle's  Stove. — Ruelle's  re- 
volving drier  (Fig.  678),  on  the 
other  hand,  recalls  the  Hockin 
and  Oxland  calciner.  It  is  made 
of  two  long  truncated  cones  of 
boiler-plate,  one  inside  the  other ; 
the  inner  one  is  destined  for 
the  drying  proper,  and  the  outer 
one  allows  the  very  hot  mineral 
to  cool  down  a  little  before  it 
is  discharged  and  sent  to  be 
ground. 

The  outer  shell  runs  upon  fric- 
tion rollers,  and  both  it  and  the 


DRESSING.  597 

inner  case  have  internal  projecting  spiral  blades,  which  lift  the 
mineral  a  little  and  cause  it  to  travel  along.  At  one  end  there 
is  a  fireplace  ;  at  the  other  a  charging  hopper  and  a  dust -chamber. 
The  mineral  fed  by  the  hopper  into  the  inner  cone  is  gradually 
brought  along  by  the  spiral  blades  towards  the  fire-end,  whilst  it 
is  being  exposed  to  the  hot  gases  of  the  fire,  as  well  as  to  a  current 
of  hot  air  blown  in  by  a  fan,  and  heated  by  its  passage  through 
pipes  at  the  side  of  the  fireplace.  On  reaching  the  fire-end  of 
the  inner  cone,  the  mineral  falls  through  one  of  four  holes  into 
the  outer  shell,  and  is  now  conveyed  back  by  spiral  blades  to  the 
other  end,  where  it  drops  into  the  pit  of  an  elevator,  which  lifts 
it  high  enough  for  the  hopper  of  the  mills.  Any  dust  carried  off 
by  the  draught  is  deposited  in  a  chamber  built  for  that  purpose. 
This  drier  does  good  work  at  phosphate  mills. 

Rowoldt's  Stove. — This  stove,  which  is  specially  designed  for 
brown  coal,  is  made  up  of  a  number  of  small  lattice-like  shelves 
down  which  the  mineral  gradually  drops,  while  surrounded  by 
air  warmed  to  75°  C.  (167°^.)  by  its  passage  through  small  pipes 
heated  by  steam. 

Steam  Stove. — The  steam  stove,  also  designed  for  brown  coal,  is 
somewhat  like  the  ordinary  "  Tellerofen."  A  number  of  circular 
drying  plates  are  superposed  one  above  the  other  in  a  cylindrical 
•casing,  and  are  heated  by  steam  passing  under  them. 

Schulzs  Stove. — Schulz's  steam  stove  is  a  large  revolving  iron 
cylinder  like  a  tubular  boiler,  19  feet  to  20  feet  long,  and  7 
to  8  feet  in  diameter,  traversed  by  180  or  200  small  pipes  4  inches 
in  diameter  and  a  large  central  one.  The  cylinder  is  inclined  to 
the  horizon  at  an  angle  of  5°  to  6°.  The  exhaust  steam  from  an 
engine  is  passed  into  the  large  central  tube  and  finds  its  way 
through  holes  into  the  space  outside  it,  heating  the  small  tubes 
and  their  contents.  The  mineral  is  carefully  fed  from  a  hopper 
into  the  small  tubes  at  the  upper  end,  so  as  to  prevent  any  choking, 
for  otherwise  the  free  passage  of  the  air  would  be  impeded,  and 
the  drying  would  be  very  imperfect. 

Jacobi's  Stove. — In  the  Jacobi  stove  the  mineral  falls  down 
over  a  series  of  pentagonal  cast-iron  pipes  heated  by  the  passage 
of  steam,  instead  of  the  plain  lattice-like  shelves  of  the  Rowoldt 
apparatus,  in  addition  to  being  exposed  to  an  atmosphere  of  hot 
air. 

Many  of  the  brown-coal  driers  are  specially  designed  so  that 
the  products  of  combustion  of  the  fire  do  not  come  into  contact 
with  the  mineral,  for  fear  the  charge  might  be  ignited  accidentally. 
This  difficulty  does  not  crop  up  with  many  of  the  other  minerals 
which  have  to  be  dried,  though  it  is  important  with  some  that 
the  degree  of  heat  to  which  they  are  exposed  should  not  be  too 
great. 

(4)  LIQUEFACTION  AND  DISTILLATION.  —  The 
miner  resorts  to  melting  as  a  purifying  or  preparatory  process  in 


598  ORE  AND  STONE-MINING. 

treating  amber,  antimony  ore,  asphalt,  ozokerite,  and  sulphur; 
and  in  the  very  exceptional  case  of  carbonic  acid,  a  gas  is  com- 
pressed to  the  liquid  state. 

Small  lumps  of  amber,  after  having  had  the  dark  outer  rind 
dissolved  away,  are  melted  together  before  being  sold  to  the 
varnish  merchants.* 

The  liquation  of  antimony  ore  is  usually  regarded  as  a  metal- 
lurgical process ;  but  if  a  mere  melting  is  carried  on  at  the  mine 
in  order  to  rid  an  ore  of  earthy  matters,  there  is  no  more  reason 
for  refusing  this  operation  a  place  among  "  dressing "  processes, 
than  there  would  be  for  excluding  the  similar  purification  of 
asphalt,  ozokerite,  or  sulphur.  This  is  an  instance  of  the  difficulty 
of  defining  the  boundaries  between  the  province  of  the  miner  and 
that  of  the  smelter.  The  domain  of  the  former  is  already  so 
large  that  it  does  not  require  to  be  extended  unnecessarily,  and 
as  the  liquation  of  antimony  ore  is  fully  described  in  many 
metallurgical  text-books  the  process  may  be  dismissed  here  in  a 
very  few  words.  It  is  based  upon  the  easy  fusibility  of  stibnite. 
The  impure  ore  coming  from  the  mine  is  subjected  to  the  action 
of  heat  in  pots  or  tubes ;  the  stibnite  melts,  trickles  away  from 
the  earthy  matters  with  which  it  is  mixed,  runs  into  moulds  and 
is  allowed  to  cool  gradually,  furnishing  the  crude  antimony  of 
comm'erce. 

Trinidad  pitch  is  purified  or  refined  in  the  island  by  being 
melted  in  iron  pans ;  much  of  the  intermingled  earthy  matter 
sinks,  and  the  supernatant  comparatively  pure  product  is  ladled 
out  into  moulds. 

The  asphalt  rock  of  Seyssel  t  is  prepared  for  the  market  by 
melting  it  up  with  Trinidad  pitch,  or  pitch  obtained  from  bitu- 
minous sandstone,  in  the  proportion  of  i  of  pitch  to  14  of  the 
finely  crushed  rock.  When  the  mixture  has  become  pasty,  it  is 
cast  into  blocks  weighing  about  J  cwt.  each.  These  are  now 
ready  for  sale  for  making  pavements. 

The  sponge-like  masses  of  gold  obtained  by  the  distillation 
of  amalgam  are  melted  in  crucibles  and  cast  into  ingots  for 


The  comparatively  clean  pieces  of  ozokerite,  which  have  been 
picked  out,  below  and  above  ground,  and  scraped  clean,  are 
more  fully  purified  by  melting;  the  heavy  refuse  sinks  to  the 
bottom,  whilst  the  pure  wax  is  decanted  off  and  poured  into 
cylindrical  moulds. 

By  far  the  greater  portion  of  the  native  sulphur  of  Sicily  is 
extracted  from  the  limestone,  or  other  rock  by  which  it  is  accom- 
panied, by  a  simple  process  of  liquation  in  kilns ;  the  necessary 
heat  is  produced  by  the  combustion  of  part  of  the  sulphur  in 
the  rock,  it  being  cheaper  in  Sicily  to  do  this  than  to  import 

*  B.  u.  li.  Z.,  1887,  p.  24. 

f  Malo,  UAsphalte,  Paris,  1888,  p.  52. 


DRESSING. 


599 


fuel.  The  "  calcarone,"  *  or  large  kiln  (Figs.  679  and  680),  as 
distinguished  from  the  "  calcarella "  or  small  one,  is  a  circular 
pit  surrounded  by  a  wall,  having  a  sloping  bed  leading  to  a 
rectangular  aperture  in  front.  The  bed  is  covered  with  a  layer 
of  burnt  refuse  (ginese)  from  a  previous  operation,  which  is 
stamped  down  hard.  The  charging  proper  then  begins,  the 
large  lumps  are  placed  on  the  bottom,  and  various  small 
vertical  chimneys  are  left  as  passages  for  the  air;  when  the 
"  calcarone  "  is  full  up  to  the  level  b  e,  the  mineral  is  heaped  up  so 
as  to  form  a  conical  pile  b  c  d  e,  which  is  covered  over  with  a 

FIG.  679. 


PLAN 

layer  of  fine  "  ginese."  The  thickness  of  the  outer  covering  of 
refuse  varies  according  to  the  season.  The  total  charge  of  a 
large  "calcarone"  may  be  as  much  as  700  tons.  The  aperture  / 
in  front  is  closed  with  a  thin  wall,  built  with  plaster  of  Paris,  and 
the  charge  is  lit  at  the  little  chimneys.  The  heat  produced  by 
the  combustion  of  part  of  the  sulphur  liquefies  the  remainder, 
which  gradually  runs  down  the  bed  to  the  front  wall,  and  is  either 
tapped  from  time  to  time  or  is  allowed  to  escape  continuously 
into  moulds.  Some  of  the  large  "  calcaroni  "  take  three  months 
before  they  are  burnt  out  completely. 

It  is  reckoned  that  one-third  or  even  two-fifths  of  the  sulphur 

*  Parodi,  SuWestrazione  dello  solfo  in  Sicilia,  Florence,  1873,  p.  49.     The 
word  "  calcherone  "  is  also  used. 


6oo  OEE  AND  STONE-MINING. 

in  the  rock  are  consumed  in  liquefying  the  part  that  is 
obtained.  This  immense  loss  of  such  a  valuable  material  has 
very  naturally  caused  inventors  to  turn  their  attention  to  cheaper 
methods  of  extraction;  but  even  as  late  as  the  year  1889, 
nearly  seven-eighths  of  the  total  quantity  of  sulphur  obtained  in 
Sicily  were  extracted  by  the  "  calcarone  "  process.  A  little  was  got 
by  a  steam  extractor  and  about  10  per  cent,  of  the  total  pro- 
duction by  Gill's  regenerative  furnace ;  *  the  former  is  an  iron 
vessel  into  which  steam  is  conducted  after  it  has  been  filled  with 
mineral ;  the  sulphur  melts  under  the  action  of  heat  and  runs 
out  at  the  bottom. 

Rich  sulphur  rock  is  sometimes  subjected  to  distillation  in 
iron  retorts  in  order  to  extract  the  valuable  element  with  less 
loss  than  that  of  the  kilns,  and  the  process  is  also  employed  in 
expelling  mercury  from  amalgam. 

In  order  to  produce  a  commercial  article  suitable  for  despatch 
to  a  distance,  the  natural  carbonic  acid  of  Germany  is  compressed 
into  the  liquid  state.  The  gas  coming  from  the  bore-hole  is  led  to  a 
double  pump.  The  first  pump  compresses  the  gas  to  a  certain 
extent,  and  forces  it  through  a  worm  in  a  cooling  tank  ;  a  second 
pump  then  takes  up  the  process,  and  compressing  the  gas  still 
further  sends  it  through  a  second  cooling  worm  into  strong 
bottles,  made  of  wrought-iron  or  steel,  in  which  the  actual  lique- 
faction takes  place  at  a  pressure  of  31  atmospheres. 

The  bottles  are  of  four  sizes,  for  holding  4,  8,  10,  or  20  kilos, 
of  liquid  acid.  An  8-kilo.  bottle  weighs  37  kilos,  when  empty, 
or  45  when  full ;  the  dead  weight  which  has  to  be  transported  is 
therefore  very  great. 

(5)  MAGNETIC  ATTRACTION.— Magnetism  is  applied 
in  dressing  either  for  treating  poor  iron  ores,  in  order  to  produce 
a  concentrate  richer  in  metal  and  freer  from  noxious  elements 
than  the  crude  material,  or  for  extracting  magnetic  particles  from 
ores  of  bismuth,  copper,  gold,  lead,  or  zinc,  in  which  iron  minerals 
play  the  part  of  troublesome  refuse. 

The  machines  for  treating  ores  magnetically  may  be  classified 
as  follows : — 

Kind  of  Machine.  Name  of  Inventor  or  Machine.  Mode  of  Working. 

(         a.  Chase  ..      Wet  or  dry. 


Endless  belt 


b.  Conkling  ..      Wet. 

c.  Edison  ..      Dry. 

d.  Hoffman 

e.  Kessler 

\        /.  Lovett-Finney  .       Wet. 

(g.  Ball-Norton  ("Monarch")  .       D  -y. 
h.  Buchanan 
i.  Friederichssegen 
j-  King 
k.  Wenstrom 
Deflection  ...         /.  Edison 

*  Rivista  del  servizio  minerario  nel  1889,  Florence,  1890,  p.  83. 


DRESSING. 


601 


Endless  Belts. — (a)  The  Chase  separator*  (Fig.  681)  has  two 
endless  belts  with  magnets  underneath.  A,  B  are  two  revolving 
iron  rollers  4  inches  in  diameter  and  3  feet  long,  converted 
into  magnets  by  electric  currents,  and  the  space  between  them  is 
occupied  by  a  stationary  electro-magnet ;  C  is  a  driving  pulley, 
and  D  a  tightening  pulley.  A  cotton  belt  is  made  to  travel 
round  these  four  pulleys  in  the  direction  shown  by  the  arrow. 
F  is  another  magnetic  roller,  and  G  a  driving  pulley  for  the 
second  belt,  travelling  as  shown. 

The  ore  is  fed  on  to  the  belt  at  the  point  E,  and  on  arriving  at 
A  the  non-magnetic  waste  is  thrown  off  by  centrifugal  force,  whilst 
the  magnetic  particles  are  attracted  and  held  against  the  belt.  All 
the  time  they  are  passing  from  A  to  B  they  are  subject  to  the  in- 
fluence of  the  electro-magnet,  and  owing  to  its  construction  they 
come  under  the  influence  of  a  succession  of  poles  alternating  in 
polarity.  This  causes  the  particles  to  turn  over  constantly  and 
so  free  themselves  from  the  non-magnetic  or  slightly  magnetic 


FIG.  68 1. 


FIG.  682. 


grains,  which  fall  into  the  compartment  immediately  below  the 
belt,  destined  for  the  middlings.  The  thoroughly  magnetic  par- 
ticles travel  with  the  belt  to  B,  and  as  it  moves  up  and  the 
influence  of  B  becomes  less  sensible,  they  are  attracted  by  the 
third  magnetic  roller  F,  and  at  last  leaping  across  the  small  inter- 
vening space,  they  are  carried  up  the  belt  to  G,  where  they  drop 
off  into  the  box  containing  the  "  heads."  In  making  the  little 
jump  from  B  to  F  they  still  further  free  themselves  from  incom- 
pletely magnetic  middlings. 

(6)  The  Conkling  machine  (Fig.  682)  is  an  inclined  endless 
belt  travelling  upon  a  roller  at  each  end,  with  stationary  electro- 
magnets E  E  under  the  upper  half.  The  ore  is  fed  on  from  a 
hopper,  and  is  subjected  to  the  action  of  a  stream  of  water; 
this  washes  down  the  non-magnetic  particles,  whilst  the  magnetite 
adhering  to  the  belt  is  carried  over  the  top  end.  The  Conkling 
machine  may  therefore  be  looked  upon  as  a  Brunton  separator 

*  Sahlin,  "  Magnetic  Separation  of  Iron  Ore,"  Eng.  Min.  Jour.,  vol.  liii., 
1892,  p.  663.  This  article  gives  recent  information  on  the  subject  of 
magnetic  separation,  and  has  furnished  not  only  the  account  of  the  Chase 
machine,  but  also  many  of  the  details  concerning  some  of  the  others.  See 
also  Trans.  Amer.  List.  M.E.,  vol.  xvii.,  1890,  p.  728. 


602  ORE  AND  STONE-MINING. 

in  which  the  rich  grains  are  held  against  the  belt  by  magnetic 
attraction,  and  thus  enabled  to  resist  the  force  of  the  stream  of 
water. 

(c)  Edison's   second    separator,    which   is   used   for   the   final 
treatment  of  re-crushed  concentrates,  furnished  by  the  deflection 
machine  (p.  606),  is  an  endless  belt  placed  vertically,  with  electro- 
magnets behind  one  side;  they  attract  the  fine  particles  of  magnetite 
and  cause  them  to  adhere  sufficiently  to  be  carried  upwards,  whilst 
the  non-magnetic  grains  drop.     The  electro-magnets  are  arranged 
so  that  the  particles  travel  over  magnets  alternating  in  opposite 
polarity ;  this  causes,  as  in  the  Chase  machine,  a  succession  of 
tumbles  or  somersaults,  which  set  free  the  non-magnetic  particles 
and  allow  them  to  fall.     The  magnetite  is  carried  up  over  the  top 
roller  by  buckets  attached  to  one  side  of  the  belt. 

(d)  The  Hoffman  separator  *  (Fig.  683)  is  an  endless  belt  arranged 

horizontally    upon     the     two 

FIG.  683.  drums  A  and  B,  provided  with 

two   sets   of    magnets.      The 
I  magnets    C     and    also    those 

inside  the  drum  B  have  their 
poles     arranged     alternately. 

"W11611  the  ore  is  fed  on  to  the 
belt  from  the  hopper,  it  travels 
along  over  the  magnets  0,  and 
is  subject  to  magnetic  attrac- 
tion varying  in  amount,  ac- 
cording to  the  distance  from 
the  pole,  and  also  in  polarity.  This  action  tends  to  make  the 
magnetic  particles  group  themselves  into  a  layer  resting  imme- 
diately upon  the  belt,  whilst  the  non-magnetic  particles  lie  upon 
the  top.  On  arriving  at  B  these  latter  are  easily  thrown  off  by 
centrifugal  force,  and  fall  into  the  compartment  E,  whilst  the 
magnetic  grains  still  cling  to  the  belt.  Those  which  are  in- 
completely magnetic  drop  at  F ;  a  better  product  is  collected  at 
G,  and  a  clean  concentrate  at  H.  .  The  partitions,  which  separate 
the  waste  and  divide  the  orey  shower  into  classes  of  varying  rich- 
ness, can  be  set  so  as  to  obtain  any  kind  of  classification  which  is 
most  suitable  to  the  ore  under  treatment. 

A  blast  of  air  is  drawn  along  the  face  of  the  belt  in  the  opposite 
direction  to  that  of  its  travel,  and  helps  to  set  free  any  non- 
magnetic grains  caught  up  between  the  others. 

(e)  Kessler,f  of  Oberlahnstein,  is  the  inventor  of  a  machine 
acting  in  a  totally  different  manner  (Fig.  684).     It  is  a  broad, 
endless  belt  or  chain,  armed  with  a  number  of  iron  points,  travel- 
ling over  the  two  rollers  A  and  B  ;  the  former  is  an  electro- 

*  "  The  Hoffman  Magnetic  Separator,"  Eng.  Min.  Jour.,  vol.  lii.,  1891, 
p.  680, 

t  B.  u.  h.  Z.,  1891,  p.  382. 


DKESSING. 


603 


magnet,  the  latter  is  made  of  wood.  The  stuff*  falls  from  the 
hopper  F  into  the  conveyor  C,  which  feeds  it  across  the  whole 
width  of  the  cylinder  A,  and  then  drops  into  the  curved  gutter  G, 
where  the  iron  points  are  drawn  through  it  as  the  belt  revolves. 
The  points,  while  under  the  influence  of  the  electro-magnet  A, 
pick  up  the  magnetic  particles,  and  let  them  drop  into  the 
compartment  E  on  losing  their  power,  while  the  non-magnetic 
particles  fall  at  D.  The  partition  between  can  be  placed 


FIG.  684. 


FIG.  685. 


FIG.  686. 


in  any  suitable  position.  This  machine  has  been  used  in  Spain 
for  separating  iron  ore  from  calamine,  after  the  former  has  been 
made  magnetic  by  a  reducing  calcination. 

(/)  Lovett-Finney  machine  (Fig.  685 )  in  some  respects  resembles 
the  Conkling  separator.  It  is  a  wet  machine,  consisting  of  an  end- 
less canvas  belt  travelling  upon  two  drums,  A  and  B,  one  of  which, 
A,  has  its  outer  surface  made  of  bars  of  iron ;  these  become  magnets 
of  alternate  polarity,  as  they  are  connected  alternately  with  the 
iron  discs  forming  the  ends  of  the  drum,  which  form  the  poles  of 
an  electro-magnet.  The  ore  is  fed  against  the  belt  about  half-way 
up  the  magnetic  drum  A,  and  as  the  belt  revolves  with  the  drum, 
the  magnetic  particles  are  carried  up,  whilst  the  non-adherent 
waste  is  washed  off  by  a  stream 
of  water.  The  concentrate  is 
conveyed  over  the  pulley  B  into 
a  tank,  and  drops  off,  as  it  is  no 
longer  subject  to  the  attractive 
force. 

(g)  Rolls.— In  the  Ball-Norton 
machine  (Fig.  686)  the  magnetic 
particles  are  drawn  against  re- 
volving drums  made  of  paper  pulp, 
instead  of  being  attracted  to  the  surface  of  a  canvas  belt.  There  are 
two  drums,  A  and  B,revolvinginthesame  direction, in  each  of  which 
are  arranged  electro-magnets  capable  of  holding  magnetic  particles 
against  a  certain  portion  of  the  under  surface.  As  usual,  the  magnets 
are  alternate  in  polarity.  The  ore  is  fed  from  a  hopper  C  against 
the  roll  A,  the  tails  drop  at  once  into  D,  and  the  adherent 
magnetite  travels  along  with  the  roll  till  it  begins  to  leave  the 


604 


ORE  AND  STONE-MINING. 


FIG.  687. 


magnetic  field;  the  centrifugal  force  now  overpowers  the 
magnetic  attraction,  throwing  the  grains  against  the  roll  B. 
Those  which  are  completely  magnetic  attach  themselves  to  B,  while 
ore  mixed  with  waste  falls  into  the  compartment  E ;  lastly,  the 
clean  magnetite,  on  escaping  from  the  influence  of  the  magnets, 
yields  once  more  to  the  centrifugal  force  and  is  deposited  at  F. 
A  strong  current  of  air  is  being  constantly  drawn  through  the 
machine  in  the  opposite  direction  to  the  travel  of  the  ore  and 
assists  in  the  cleaning. 

(h)  The  Buchanan  separator*  (Fig.  687)  is 'made  of  two  cast- 
iron  rolls,  revolving  in  opposite  directions,  supported  on  the  ends 
of  an  electro-magnet ;  the  two  rolls  thus 
become  the  poles  of  a  huge  horse-shoe 
magnet,  and  the  magnetism  is  most 
strongly  developed  where  they  most 
closely  approach  each  other.  As  the  ore 
drops  down  between  the  rolls,  the  mag- 
netic particles  fly  to  them,  and  are 
carried  along  until  they  fall  off  at  the 
JS  sides,  when  the  centrifugal  force  over- 
powers the  now  diminishing  magnetic 
attraction.  The  poor  non-magnetic  par- 
ticles fall  vertically. 

(i)  Zinc  blende  found  mixed  with 
chalybite  at  Friederichssegen  is  roasted, 
so  as  to  convert  the  latter  mineral  into 
magnetite,  and  then  treated  in  the  machine  shown  in  Figures  688 
and  689.  It  is  composed  of  a  brass  cylinder  A,  with  a  number  of 
little  ridges  S,  parallel  to  the  axis,  and  four  sets  of  stationary 
electro-magnets  B.  T  is  the  ore-hopper  which  supplies  the  feeder 
D :  this  is  a  sheet-iron  tray,  which  is  made  to  oscillate  by  cams 
upon  a  little  shaft  driven  by  the  pulley  Q.  P  is  the  main  belt 
pulley  upon  H,  the  shaft  of  the  brass  drum,  and  R  is  a  pulley 
which  drives  Q  by  a  belt.f 

A  regular  stream  of  fine  ore  is  fed  against  the  brass  cylinder  by 
the  feeder  D,  and  the  grains  of  blende  at  once  fall  into  the  com- 
partment Z ;  the  magnetic  oxide  of  iron  is  held  against  the 
cylinder  by  the  attraction  of  the  electro-magnets,  and  is  carried 
over  by  the  little  longitudinal  ridges  until  it  falls  into  the  com- 
partment F. 

(j)  King's  I  magnetic  dressing  machine  works  by  the  aid  of 
permanent  magnets  fixed  upon  a  revolving  drum.  Like  other 
inventors  he  arranges  his  magnets  so  that  their  poles  alternate, 

*  Eng.  Min.  Jour.,  vol.  xxxv.,  1883,  p.  133  ;  vol.  xlvii.,  1889,  p.  542. 

t  Bellom,  "  Etat  actuel  de  la  preparation  mecanique  dans  la  Saxe,  le 
Hartz  et  la  Prusse  Rhenane,"  Annales  des  Mines,  ser.  8,  vol.  xx.,  1891,  p.  5  ; 
B.  u.  h.  Z.,  1892,  p.  37. 

J  Fifty-third  Ann.  Hep.  B.  Corn.  Pol.  Soc.     Falmouth,  1885,  P-  44- 


DRESSING. 


605 


and  he  thus  makes  the  grains  tumble  over  and  shake  off  any 
loosely  intermingled  non-magnetic  particles. 

(k)  The  Wenstrom  *  is  a  Swedish  machine,  which  has  been  in  use 
at  Dannemora  and  other  mines  for  some  years  (Fig.  690).  It  has  a 
stationary  electro-magnet  A,  and  a  revolving  armature  barrel  B,. 
consisting  of  a  number  of  soft  iron  bars  separated  by  strips  of 

FIG.  688. 


Scale'/™ 

wood.  The  electro-magnet  lies  on  one  side  of  the  centre  of  the 
barrel,  so  that  the  iron  bars  of  the  armature  become  magnetised 
only  during  part  of  the  revolution.  C  is  a  tray  feeding  the  ore 
on  to  the  top  of  the  barrel,  D  a  shoot  for  the  non-magnetic 
particles,  and  E  the  shoot  for  the  concentrate.  The  magnetic 
grains  adhere  to  the  soft  iron  bars  when  these  are  close  to  the 
electro-magnet,  and  are  carried  past  D  as  the  barrel  revolves; 

*  E.  M.  /.,  vol.  xlvi.,  1888,  p.  437.     B.  u.  h.  Z.,  1891,  p.  178. 


606  ORE  AND  STONE-MINING. 

as  the  bars  recede  from  the  electro-magnet,  they  lose  their  power 
and  let  the  iron  ore  drop  into  E. 

(1)  Deflection. — The  simplest  of  all  magnetic  separators  is  one 
devised  by  Edison  (Fig.  691).*  It  is  based  upon  the  fact  that  if  a 
thin  sheet  of  finely  crushed  ore  drops  past  a  powerful  electro- 
magnet, the  magnetic  particles  will  be  drawn  towards  it  and 
deflected  from  their  direct  downward  path,  whereas  the  non- 
magnetic particles  will  fall  vertically.  If  a  partition  is  fixed  in  a 
suitable  manner,  the  concentrate  falls  on  one  side  and  the  waste 
on  the  other.  Diagrammatically  the  machine  may  be  shown 
thus  : — A  A  represent  the  electro-magnets,  B  a  hopper  delivering 
the  fine  ore  through  a  long  narrow  slit;  C  is  a  thin  partition. 
The  waste  falls  vertically  into  the  compartment  D,  and  the  iron 
ore  into  E. 

Magnetic   separators  are   chiefly   used  for  concentrating   the 

FIG.  690.  FIG.  691. 


magnetite  from  ores  that  are  too  poor  to  go  to  the  furnace  in  the 
orude  state ;  and  it  has  been  proposed  to  make  brown  haematite 
magnetic  by  partial  reduction  at  a  low  red-heat,  but  other  uses 
have  been  mentioned  in  describing  the  various  machines.  For 
instance,  by  the  ordinary  washing  processes  it  is  impossible  to 
separate  chalybite  with  a  density  3-7  to  3*9  from  blende  with  a 
density  of  3*9  to  4*2.  The  aid  of  magnetism  is  here  invoked  with 
success  as  already  explained. 

The  Namaqua  Copper  Company  use  King's  magnetic  separator 
for  extracting  the  magnetite  which  is  mixed  with  bornite  and 
chalcopyrite,  in  order  to  obtain  a  product  richer  in  copper. 

In  a  similar  manner  a  magnetic  concentrator  of  the  Ball-Norton 
type  has  been  employed  in  Queensland  for  treating  a  mixed  con- 
centrate of  magnetite  and  bismuth  ore,  obtained  by  a  wet-dressing 
process.  The  percentage  of  bismuth  is  raised  in  this  way  from  10 
or  12  to  20  per  cent. 

On  a  small  scale,  the  magnet  is  of  service  for  extracting  magnetic 

*  E.  M.  J.,  vol.  lix.  1889,  p.  479,  and  vol.  liii.  1892,  p.  662. 


DRESSING.  607 

particles  when  washing  samples  of  tin  ore  on  the  vanning  shovel, 
or  gold  in  the  batea. 

(6)  FRIABILITY. — Some  minerals  are  more  easily  crumbled 
and  reduced  to  powder  than  others,  and  if  the  difference  in 
friability  is  great,  it  is  possible  after  crushing  to  effect  a  separation 
by  a  mere  process  of  sifting.  An  instance  of  this  rare  method  of 
concentration  occurs  at  the  graphite  mines  near  Passau,  in 
Bavaria.*  The  softer  kinds  of  mineral  obtained  from  the  mine  are 
ground  in  mills,  when  the  thin  greasy  elastic  plates  of  graphite 
arrange  themselves  parallelly  to  the  surface  of  the  stones,  and 
preserve  their  flat  shape,  while  pieces  of  more  brittle  minerals  are 
reduced  to  the  state  of  fine  powder.  The  ground  product  is  sifted 
upon  fine  silk  cloth,  the  dust  poor  in  graphite  passes  through  the 
fine  holes,  but  the  scales  of  graphite  are  left  behind.  As  might 
be  supposed,  the  separation  is  not  very  thorough. 

Biittengenbachf  has  separated  blende  from  iron  pyrites  in  a 
somewhat  similar  way,  the  former  mineral  being  much  more  easily 
pulverised  than  the  latter.  He  used  a  Vapart  disintegrator  to 
treat  a  mixture  of  blende  and  pyrites,  in  grains  J  inch  to  §  inch 
across,  and  by  suitably  regulating  the  speed,  he  was  able  to  reduce 
the  blende  to  the  state  of  fine  sand  without  affecting  the  pyrites 
to  any  appreciable  extent.  The  blende  extracted  by  sifting  con- 
tained 50  to  55  per  cent,  of  zinc,  whilst  the  pyrites  was  almost  free 
from  this  metal. 

The  dressing  of  the  plumbiferous  sandstone  of  Mechernich  is 
probably  the  most  important  instance  of  a  difference  in  friability 
affecting  the  method  of  treatment.  The  little  concretions  of 
galena  and  quartz  are  comparatively  hard  and  the  sandstone  very 
friable.  The  greater  part  of  the  stuff  coming  from  the  mine  has 
crumbled  to  the  state  of  loose  sand  before  it  reaches  the  works, 
so  that  the  first  comminution,  which  sets  free  the  rich  knots,  is 
sufficiently  effected  by  the  mere  handling,  without  the  powerful 
crushing  machinery  usually  required  for  the  preliminary  treatment 
of  a  lead  ore. 

III.  PROCESSES  DEPENDING  UPON  CHEMICAL 
PROPERTIES. 

(i)  SOLUTION,  EVAPORATION,  AND  CRYSTALLI- 
SATION.— Processes  of  this  kind  are  employed  by  the  miner  in 
some  of  the  few  cases  where  the  mineral  is  soluble  in  water ;  aid 
is  derived  from  certain  other  solvents,  such  as  benzine  and  hydro- 
chloric acid. 

The  principal  minerals  soluble  in  water  are  borax,  nitrate  of 
soda,  potassium  salts,  and  common  salt. 

*  Andree,  "Der  osterreichische  und  bayerische  Graphitbergbau," 
B.  u.  h.  Z.,  1890,  p.  270. 

t  " Auf bereitung  von  Blende  und  Schwefelkies,"  B.  u.  h.  Z.,  1881, 
p.  294. 


608  ORE  AND  STONE-MINING. 

The  crude  borax  of  California*  is  ground  and  thrown  into 
a  pan  containing  a  boiling  saline  solution,  frequently  the  mother- 
liquor  from  the  second  crystallisation.  The  salts  dissolve  and  the 
sand  sinks  to  the  bottom.  The  hot  solution  is  allowed  to  stand  so 
as  to  clarify,  and  is  then  run  off  into  pans  and  left  to  cool  for  five 
to  nine  days,  during  which  time  the  borax  crystallises  out.  The 
crystals  obtained  in  this  way  are  somewhat  impure.  They  are 
refined  by  being  dissolved  and  allowed  to  crystallise  a  .second  time. 

Nitrate  of  soda  is  treated  on  a  larger  scale. f  The  caliche, 
crushed  into  lumps  about  2  inches  across,  is  tipped  into  large 
rectangular  boiling  tanks  full  of  water,  which  are  heated  by  a 
spiral  3 -inch  steel  pipe  with  steam  at  a  pressure  of  60  Ibs.  to 
the  square  inch.  The  boiling  is  carried  on  by  Shanks'  lixiviating 
system,  which  causes  a  continual  circulation  of  the  lighter  liquid 
to  the  other  boiling  tanks  by  following  the  denser  and  heavier 
solution.  As  soon  as  the  solution  is  concentrated  to  no  by 
Twaddell's  hydrometer,  it  is  allowed  to  settle  for  a  short  time, 
and  is  then  drawn  off  to  the  crystallising  tanks.  The  refuse  in 
the  boiling  tanks  is  again  treated  with  water  in  order  to  extract  a 
little  nitrate  which  it  still  contains. 

The  crystals  are  shovelled  out  on  to  drying  floors  and  put  up 
in  sacks  for  export. 

The  mother-liquor,  which  contains  a  little  sodium  iodate,  is 
added  to  the  water  used  for  dissolving  a  fresh  stock  of  "  caliche," 
and  by  repetitions  of  the  process  it  becomes  rich  enough  for  the 
extraction  of  the  iodine ;  this  is  precipitated  by  sodium  bisulphite, 
washed  and  pressed  into  cakes.  The  crude  iodine  so  obtained  is 
purified  by  sublimation. 

The  principal  potassium  salt  of  Stassf urt  is  carnallite,  a  hydrated 
double  chloride  of  potassium  and  magnesium.  Some  of  it  is  treated 
on  the  spot  in  order  to  produce  commercial  chloride  of  potassium. 

The  crude  mineral,  after  being  coarsely  ground,  is  treated  with 
hot  water,  and  the  strength  of  the  solution  is  so  arranged  that  only 
the  chlorides  of  potassium  and  magnesium  are  dissolved  out.  The 
residues  are  treated  with  cold  water  which  dissolves  out  some 
sodium  chloride  and  leaves  behind  kieserite  (hydrated  magnesium 
sulphate).  This  is  passed  through  a  fine  sieve,  moulded  into 
blocks,  and  sold. 

The  solution  of  the  chlorides  of  potassium  and  magnesium  is 
allowed  to  settle  and  cool,  and  three  products  are  obtained  from 
it :  (a)  crystals  of  potassium  chloride ;  (b)  mother-liquor ;  (c)  slimes. 

The  crystals  (a)  still  contain  a  little  sodium  chloride.  They  are 
lowered  into  water  in  iron  vessels  and  much  of  the  sodium  chloride 

*  C.  Napier  Hake,  "An  Account  of  a  Borax  Lake  in  California,"  Jour. 
Soc.  Cliem.  2nd.,  vol.  viii.,  1889,  p.  854. 

t  Harvey,  "  Machinery  for  the  Manufacture  of  Nitrate  of  Soda  at  the 
Kamirez  Factory,  Northern  Chili,"  Proc.  Inst.  C.  E.,  vol.  Ixxxii.,  1884-85, 
P-  337- 


DRESSING.  609 

is  dissolved  out ;  they  now  contain  80  per  cent,  of  potassium  chloride, 
and  after  being  freed  from  moisture  in  Thelen's  drier,  they  are 
packed  in  bags  and  sold. 

The  mother-liquor  (6)  is  heated  and  gives  crystals  of  artificial 
carnallite,  which  are  treated  again  in  the  same  way  as  the  native 
mineral.  On  evaporation  the  final  mother-liquor  yields  hydrated 
magnesium  chloride. 

The  slimes  (c)  are  put  into  a  filter  press,  and  the  solid  cakes 
so  obtained  are  calcined  and  sold  as  manure  after  being  ground. 
They  owe  their  fertilising  value  to  some  potassium  chloride  which 
they  still  contain. 

The  evaporation  of  brine  may  be  carried  out  naturally  or 
artificially.  In  Southern  Europe,  and  in  other  countries  where 
the  sun  has  sufficient  power,  sea-water  led  into  shallow  ponds 
gradually  becomes  concentrated  enough  to  deposit  salt.  In 
Germany,  weak  brine  is  strengthened  by  allowing  it  to  trickle 
down  through  brush-wood  contained  in  huge  frameworks  of 
timber.  A  great  surface  is  thus  exposed  to  the  atmosphere  with 
much  evaporative  effect  if  the  weather  is  dry. 

In  this  country  common  salt  is  mostly  obtained  from  brine 
pumped  up  out  of  bore-holes  or  out  of  inundated  salt  mines. 
After  being  allowed  to  settle,  the  brine  is  evaporated  in  large 
sheet-iron  pans  heated  by  the  flame  of  a  coal  fire  passing  under- 
neath along  flues.  Some  of  the  pans  in  the  Middlesbrough  district 
are  70  feet  long  and  24  feet  wide,  with  a  depth  of  20  inches  at 
the  fire-end,  and  gradually  lessening  to  16  inches  at  the  other. 
In  Cheshire,  even  larger  pans  may  be  seen,  some,  in  fact,  as  much 
as  TOO  feet  long  by  45  feet  wide.  The  heat  of  the  fire  gradually 
drives  off  the  water,  and  crusts  of  salt  form  on  the  surface ;  they 
fall  to  the  bottom  and  are  shovelled  out ;  after  being  allowed  to 
drain,  the  salt  is  ready  for  despatch  to  the  alkali  works. 

At  Bex,  in  Switzerland,  where  fuel  is  dear  and  water-power 
abundant,  the  brine  is  evaporated  in  a  closed  boiler,  like  a  large 
egg-ended  steam  boiler,  heated  from  below;  the  process  of 
evaporation  goes  on  continuously,  brine  being  constantly  pumped 
in  and  salt  being  drawn  off  as  it  is  deposited. 

Benzine  is  employed  in  the  exceptional  case  of  ozokerite  for  dis- 
solving out  remnants  of  the  mineral  left  in  some  of  the  residues. 

Heavy  spar  stained  by  oxide  of  iron  is  "  bleached  "  by  sulphuric 
acid ;  the  mineral,  after  being  crushed  to  the  state  of  coarse 
powder,  is  put  into  lead-lined  vats  with  dilute  sulphuric  acid, 
which  is  brought  to  the  boiling-point  by  the  injection  of  steam. 
The  acid  dissolves  the  oxide  and  leaves  white  barytes  ready  for 
grinding  after  it  has  been  dried. 

Tin  ore  contaminated  with  copper  ore  may  be  freed  from  the 
latter  metal  by  hydrochloric  acid  ;  the  so-called  "  burnt  leavings," 
that  is  to  say  the  tailings  produced  in  washing  the  roasted 
•concentrates  of  tin  ore,  originally  enveloped  or  accompanied  by 

2  Q 


6 jo  ORE  AND  STONE-MINING. 

sulphides,  are  treated  with  hydrochloric  acid ;  the  coppery  solution 
is  led  into  pits,  where  the  metal  is  precipitated  by  iron. 

(2)  ATMOSPHERIC  WEATHERING.— I  must  point  out 
that  though  weathering  often  results  from  mere  loss  of  water, 
it  may  in  other  cases  be  caused  by  the  chemical  decomposition  of 
one  of  the  minerals  contained  in  the  stuff  under  treatment.  As 
already  stated,  the  boundaries  between  the  various  dressing  pro- 
cesses are  not  distinctly  defined. 

The  crumbling-up  of  the  diamond-bearing  rock  under  atmospheric 
agencies  plays  an  important  part  in  the  extraction  of  the  gems, 
and  with  no  other  mineral  is  a  weathering  action  of  this  kind 
carried  out  on  so  large  a  scale  or  in  such  a  systematic  manner. 
The  floors  devoted  to  this  process  at  De  Beers*  mine  occupy 
some  thousands  of  acres.  They  are  merely  fairly  level  ground 
from  which  the  bush  and  grass  have  been  removed,  and  which 
has  been  rolled  to  make  it  hard.  The  ground  is  laid  out  in 
rectangular  sections,  600  yards  long  and  200  wide,  and  is  enclosed 
by  high  wire  fences.  Main  lines  of  rails  on  each  side  of  the 
floors  and  subsidiary  portable  lines  serve  to  bring  the  trucks  of 
"blue,"  which  is  tipped  and  spread  out  so  that  a  load,  i.e.,  16 
cubic  feet  or  1600  Ibs.,  will  occupy  an  area  of  21  square  feet. 

After  being  left  for  some  time,  the  "  blue  "  is  broken  up  by 
means  of  picks  into  pieces  not  larger  than  4  inches  cube,  and 
is  again  left  to  dry  for  a  farther  period,  until  most  of  the  natural 
water  has  evaporated.  The  artificial  "  diamond  field  "  is  then 
watered,  to  aid  the  disintegration,  and  lastly  harrowed  and  rolled  ; 
in  fact,  the  miner  endeavours  to  bring  about  the  pulverisation 
somewhat  in  the  same  way  that  the  farmer  prepares  his  land  for 
tillage. 

The  stuff  is  known  at  first  as  "coarse  blue  ground,",  then  as 
"  broken  blue  ground,"  and  finally,  after  the  rolling,  as  "  pulverised 
blue  ground." 

The  length  of  time  required  for  this  disintegration  depends  not 
only  upon  the  atmospheric  conditions — that  is  to  say,  the  season 
of  the  year  and  the  amount  of  rain — but  also  upon  the  mine 
from  which  the  blue  is  obtained.  The  blue  from  Kimberley 
mine  becomes  sufficiently  disintegrated  in  three  months  in 
summer,  whilst  the  De  Beers  blue  requires  double  that  time.  It 
is  evident,  therefore,  that  a  very  large  stock  of  blue  has  to  be 
kept  on  the  floors,  if  the  washing  machines  are  to  be  supplied 
regularly. 

The  diamond  is  not  the  only  gem  which  may  be  released  from 
its  matrix  by  disintegration  under  atmospheric  agencies.  The 
garnetiferous  gravel  of  Bohemia  f  was  at  one  time  allowed 

*  De  Beers  Consolidated  Mine?,  Limited,  Second  Annual  Report  for  the 
Year  ended  $ist  March,  1890,  p.  18. 

f  Kaymond,  Discussion  upon  Kunz's  paper  on  "  Bohemian  Garnets," 
Irans.  Amer.  Inst.  M.  E.t  vol.  xxi.,  1892,  p.  249. 


DRESSING.  611 

to  weather  for  three  months  on  the  surface,  in  order  to  fit  it  for 
the  subsequent  washing  process. 

Phosphate  of  lime  occurring  in  the  form  of  nodules  in  clay  is 
treated  in  a  like  manner.  The  phosphate  dug  from  open  pits  in 
the  Lias  in  the  department  of  the  Haute-Saone  *  is  left  exposed 
to  the  air  often  all  the  winter ;  a  part  of  the  earthy  matter  falls 
off,  and  the  nodules  have  simply  to  be  screened  dry,  in  order  to 
separate  a  large  portion  of  the  clay  with  which  they  were 
only  originally  mixed.  Again,  in  the  Yosges  there  is  a  phos- 
phatic  bed  of  the  same  geological  age,  consisting  of  soft  nodules 
forming  only  -—^  or  ^  of  the  bed  of  brown  clay  by  which  they 
are  enveloped.  The  stuff  is  spread  out  on  the  fields  and  raked 
over  occasionally.  The  clay  crumbles  off,  and  at  the  same  time 
the  nodules  harden  from  losing  their  moisture ;  they  are  then 
picked  out  by  hand. 

Nodules  of  clay  ironstone  are  freed  from  shale  in  a  similar 
way ;  and  ores  of  iron  more  or  less  contaminated  with  iron  or 
copper  pyrites  gradually  have  a  portion  of  their  sulphur  washed 
out  in  the  form  of  soluble  sulphates,  if  exposed  for  a  sufficient 
time  to  the  action  of  air  and  rain. 

Fire-clay  is  found  to  be  better  suited  for  making  bricks  after 
weathering  for  some  months,  than  when  first  raised  from  under- 
ground. 

(3)  CALCINATION  OB  ROASTING.— The  object  of 
calcination  or  roasting  may  be  : 

a.  To  effect  a  change  in  the  chemical  composition  of  a  valuable 
mineral,  and  so  produce  either  an  ordinary  article  of  commerce  or 
one  that  is  more  readily  saleable  than  the  raw  material. 

b.  To  effect  a  change  in  the  chemical  composition  of  some  of 
the  substances  accompanying  a  valuable  mineral,  and  so  get  rid 
of  them  partially  or  render  them  more  easily  separable  by  other 
processes. 

The  commonest  example  which  can  be  cited  is  burning 
limestone  ;  the  action  of  heat  is  made  use  of  to  drive  off 
the  carbonic  acid  and  leave  quicklime.  Another  instance  is 
furnished  by  clay  ironstone,  or  any  ore  in  which  the  iron  occurs 
mainly  in  the  form  of  carbonate.  Simple  exposure  to  heat  con- 
verts ferrous  carbonate  into  magnetic  oxide ;  the  former  contains 
48  per  cent,  of  iron,  the  latter  7  2  per  cent. ;  consequently,  if  the 
ore  has  to  be  sent  to  a  distance  there  is  a  saving  in  freight, 
besides  which  the  ore  is  more  acceptable  to  the  ironmaster  for  his 
furnaces. 

Gypsum  is  calcined  in  order  to  expel  the  water  chemically 
combined  with  it,  and  convert  it  into  plaster  of  Paris. 

With  the  ores  of  arsenic,  it  is  the  valuable  ingredient  which  is 
driven  off.  Mispickel  and  other  arsenical  ores  are  roasted  at 

*  titatistique  del 'Industrie  mintrale  en  France  et  en  Algtrie  en  1 886,  Paris, 
1888,  p.  268  and  p.  282. 


612  ORE  AND  STONE-MINING. 

mines  in  order  to  produce  arsenious  acid,  which  is  collected  in 
special  flues. 

Ores  of  copper  are  sometimes  calcined  at  mines,  with  the 
object  of  extracting  the  arsenic  before  sale  to  the  smelters,  who 
would  pay  nothing  for  this  latter  metal  and  prefer  its  absence. 

Calcination  is  resorted  to  in  the  case  of  some  iron  ores  in  order 
to  get  rid  of  the  sulphur,  due  to  intermixed  iron  pyrites  or  pyrrho- 
tine,  and  so  free  the  ore  from  an  element  which  the  smelter  dislikes. 
Thus  in  Northamptonshire  the  undecomposed  greenish  lumps  in 
the  bed  are  picked  out  on  account  of  the  sulphur  they  contain, 
and  put  aside.  When  a  sufficient  quantity  has  accumulated,  a 
heap  is  made  with  a  little  coal  and  fired ;  the  ore  loses  nearly  all 
its  sulphur  in  the  burning  and  is  thus  fitted  for  the  blast- 
furnace. 

Auriferous  ores  are  roasted  in  some  instances  for  the  purpose 
of  liberating  the  gold  which  is  so  enveloped  in  sulphides  and 
sulpharsenides,  such  as  iron  pyrites  and  mispickel,  as  to  be  caught 
with  difficulty  by  mercury. 

Partially  concentrated  tin  ore  (whits)  is  roasted  in  order  to 
convert  iron  pyrites  and  mispickel  into  pulverulent  oxides  which 
can  easily  be  separated  by  washing.  Again,  tin  ore  is  occasionally 
associated  with  a  considerable  amount  of  wolfram,  which 
approaches  it  so  closely  in  density  that  separation  by  washing  is 
impossible.  The  mixed  concentrate  obtained  by  the  ordinary 
dressing  processes,  consisting  of  cassiterite  mixed  with  wolfram, 
is  roasted  with  carbonate  or  sulphate  of  soda;  soluble  tungstate 
of  soda  is  produced,  which  is  dissolved  out  by  water,  leaving 
behind  the  insoluble  cassiterite  fit  for  the  smelter. 

Lastly,  we  may  take  the  case  of  zinc  ore.  Blake  *  renders  the 
separation  of  blende  from  marcasite  commercially  possible,  by 
roasting  the  mixed  minerals  at  a  temperature  sufficient  to  convert 
the  latter  into  oxide,  while  the  former  remains  unchanged.  The 
difference  in  specific  gravity  is  then  sufficient  to  allow  the  ordi- 
nary washing  processes  to  take  effect.  Smithsonite  mixed  with 
limonite  f  is  roasted  with  coal  in  order  to  reduce  the  ferric  oxide 
to  the  state  of  magnetic  oxide,  and  thus  render  it  separable  by  a 
magnetic  process. 

It  now  remains  to  be  seen  how  calcination  is  carried  out. 
Minerals  may  be  burnt  in  heaps,  in  kilns  and  in  furnaces. 

Clay  ironstone  is  usually  burnt  in  heaps  with  the  addition  of  a 
little  coal ;  but  one  variety,  black  band  ironstone,  contains  a 
sufficient  amount  of  carbonaceous  matter  to  burn  of  itself. 

The  spat  hose  ore  underlying  the  limonite  ("  rubio  ")  at  Bilbao 
is  now  being  successfully  calcined  on  a  very  large  scale  previous 
to  shipment.  According  to  Mr.  Windsor  Kichards,J  the  raw  ore 

*  "  The  Separation  of  Zinc  Blende  from  Iron  Pyrites. "  Trans.   Amer. 
Imt.  M.  H.,  vol.  xxii.,  1893-4  ;  and  (t)  Payne  in  the  Discussion. 
J  "Pres.  Address  to  I.  and  S.  Inst.,"  Coll  Guard.,  vol.  lxv.}  1893,  p.  955. 


DRESSING.  613 

contains  43  per  cent,  of  iron  and  25  per  cent,  of  carbonic  acid, 
whilst  the  calcined  ore  gives  58  per  cent,  of  iron  and  only  2  per 
cent,  of  moisture.  One  of  the  large  kilns  gets  through  1500  tons 
of  raw  ore  weekly. 

The  commonest  example  of  calcination  in  kilns  is  making 
lime.  At  large  works  the  time-honoured  semi -spheroidal  kiln 
with  intermittent  action  is  often  supplanted  by  the  Hofmann 
kiln,  in  which  the  processes  of  charging,  burning,  arid  discharging 
go  on  continuously. 

Some  of  the  baking  ovens  used  for  converting  gypsum  into 
plaster  of  Paris,  by  the  simple  expulsion  of  the  water  of  combi- 
nation, are  cylindrical  brick  kilns  so  arranged  that  the  flame 
nowhere  comes  in  contact  with  the  mineral.  The  fireplace  is  in 
the  centre,  and  the  hot  gases  are  drawn  down  flues  into  an 
annular  arched  passage  all  round  the  bottom  of  the  kiln,  and 
then  ascend  through  the  charge  by  means  of  a  number  of 
cast-iron  pipes.  The  kiln  is  covered  by  a  brick  dome  over 
which  comes  a  conical  hood  or  chimney. 

In  making  Parian  cement  from  gypsum  a  different  oven  is 
employed,  in  which  a  central  coke  fire  sends  out  its  hot  gases 
directly  on  to  the  charge  itself. 

The  furnaces  used  by  the  miner  are  usually  of  the  reverberatory 
type,  in  which  the  flame  plays  into  the  space  containing  the 
charge ;  the  bed  may  be  stationary  or  revolving.  The  two  most 
frequently  employed  in  Cornwall  and  Devon,  for  roasting  the 
ores  of  arsenic,  copper  and  tin,  are  Brunton's  calciner  and 
Hockin  and  Oxland's  calciner.  The  former  (Fig.  692)  *  has  a 
revolving  circular  bed  about  10  feet  in  diameter,  supported  by  a 
vertical  shaft,  which  is  made  to  revolve  slowly  by  any  convenient 
source  of  power,  whilst  the  flames  of  two  fireplaces  at  the  sides 
play  upon  it  and  produce  the  requisite  amount  of  heat.  Depend- 
ing from,  cast-iron  frames  fixed  in  the  roof  of  the  furnace,  are 
three  sets  of  knives  or  teeth,  inclined  in  such  a  manner  as  to 
shift  the  ore  gradually  from  the  centre,  where  it  is  fed  on, 
towards  the  circumference,  where  it  is  discharged.  The  action  of 
heat  in  the  presence  of  atmospheric  oxygen  converts  the  sulphur 
and  arsenic  into  sulphurous  and  arsenious  acids,  which  escape 
with  the  other  hot  gases,  and  are  led  into  long  condensing  flues. 
These  are  brick  or  stone  passages  high  enough  for  a  man  to 
stand  upright,  with  partial  partitions  so  arranged  as  to  make 
the  hot  gases  take  a  tortuous  path.  There  are  large  openings 
on  one  side  for  drawing  out  the  arsenical  soot  at  intervals. 
During  the  actual  calcination  these  doors  or  manholes  are  closed 
by  sheets  of  iron  carefully  luted  with  clay. 

The  Hockin  and  Oxland  calciner  is  not  unlike  the  Bruckner 
furnace  used  in  the  United  States,  as  it  is  a  revolving  cylinder 

*  Hendersofi.     Op.  cit. 

TTN1 


614 


OKE  AND  STONE-MINING. 


lined  with  fire-brick.  Figures  693  and  694*  show  the  construction 
of  such  a  furnace.  A  is  the  cylinder  lined  with  fire-brick,  set  at  a 
slight  inclination  and  supported  on  rollers.  It  is  made  to  revolve  at 
the  rate  of  six  to  eight  revolutions  per  hour  ;  B  is  a  screw  which 

FIG.  692. 


brings  down  a  regular  supply  of  ore  from  a  hopper.  The  ore 
travels  along  very  gradually  in  the  direction  of  the  arrow  and 
finally  drops  into  the  chamber  C.  D  is  the  fireplace  opening  into 
the  lower  end  of  the  cylinder,  and  E  is  the  beginning  of  the  flues, 

*  Ferguson,  "  On  the  Appliances  used  for  Dressing  Tin  and  Copper  Ores 
in  Cornwall,"  Proc.  Inst.  Mech.  Eng.,  1873,  p.  128. 


DRESSING. 


6'S 


in  which  the  arsenious  acid  is  condensed  and  through  which  the 
sulphurous  acid  passes  on  its  way  to  the  chimney.  The  longi- 
tudinal ribs  of  fire-brick,  extending  two-thirds  of  the  length  of 
the  furnace  from  the  lower  end,  serve  to  lift  up  the  charge  and 
let  it  fall,  so  as  to  expose  new  surfaces  to  the  action  of  the  air. 
One  of  these  calciners  used  some  years  ago  at  Devon  Great 
•Consols  mine  was  simply  an  old  boiler  tube,  30  feet  long  by  3  feet 
-6  inches  in  diameter,  lined  with  4^-inch  fire-brick,  so  that  the 
clear  diameter  inside  was  2  feet  9  inches.  Another  was  made  of 
an  old  boiler  5  feet  in  diameter.  The  inclination  was  i  in  24. 


FIG.  693. 


SCALE 


20  FEET 


7  METRES 


Some  of  the  calamine  at  Monteponi,  which  has  been  concen- 
trated by  the  ordinary  wet  methods  until  it  contains  20  per  cent, 
of  zinc,  is  still  much  mixed  with  oxide  of  iron  and  dolomite.  Two 
per  cent,  of  coal  are  added,  and  the  ore  is  passed  through  the 
rotary  furnace,  42  feet  (13  m.)  long,  working  continuously  like 
the  Hockin  and  Oxland  calciner  ;  the  iron  is  thus  brought  to  the 
state  of  magnetic  oxide.  On  leaving  the  furnace  the  ore  is 
moistened  with  water,  which  causes  the  calcined  dolomite  to  fall 
to  powder.  It  is  next  treated  on  screens,  and  the  various  cate- 
gories produced  are  sent  separately  to  a  magnetic  concentrator.* 

*  Oest.  Zeitschr.f.  B.  u.  IF.,  vol.  xxxvii.,  1889,  p.  36;  and  Eng.  Min. 
Jour.,  vol.liv.,  1892,  p.  77. 


616  ORE  AND  STONE-MINING. 

(4)  CEMENTATION. — The  precipitation  of  copper  by  iron 
may  fairly  be  regarded  as  coming  within  the  province  of  the 
miner,  when  the  solution  flows  naturally  out  of  an  adit  level 
or  is  pumped   up  from   underground,  or  when   it   is   obtained 
artificially  as  a  by-product  in  tin-dressing.     On  the  other  hand, 
the    metallurgist    may    fairly  claim   such    operations    as    those 
conducted  on  a  huge  scale  at  Rio  Tinto,  where  the  cupreous 
solution  is  mainly  produced  by  leaching  the  ore  which  has  been 
burnt  in  heaps,  or  a  mixture  of  burnt  ore  and  raw  ore.    However, 
as  in  other  cases,  the  line  of  demarcation  between  the  two  do- 
mains is  an  arbitrary  one,  and  on  this  account  it  is  advisable  that 
the  mining  student  should  be  well  grounded  in  metallurgy. 

The  famous  old  Parys  mine  in  Anglesey,  now  shorn  of  its  glory 
owing  to  the  low  price  of  copper,  affords  the  most  important 
example  of  cementation  carried  on  at  a  mine  in  this  country. 
Coppery  water  is  pumped  out  of  the  mine,  and  is  led  into 
brick-lined  pits  containing  scrap-iron.  The  iron  is  raked  over 
from  time  to  time,  and  eventually  the  old  pots,  kettles,  shovels, 
meat-tins,  &c.,  pass  into  solution,  while  the  copper  is  precipi- 
tated. As  might  be  imagined,  when  one  looks  at  the  heterogeneous 
mixture  of  articles  constituting  the  scrap-iron  thrown  into  the 
pits,  the  precipitate  is  very  impure  and  contains  only  some  20  to 
30  per  cent,  of  metallic  copper. 

The  iron  used  is  not  lost ;  the  ferruginous  solution  running 
away  from  the  precipitating  pits  is  led  into  large  pools,  and 
there  exposed  to  the  action  of  air  and  rain.  The  dissolved  iron 
gradually  passes  to  a  higher  state  of  oxidation,  producing  in- 
soluble ochre,  and  little  by  little  a  deposit  of  this  substance  forms 
upon  the  bottom  of  the  big  ponds.  According  to  the  strength  of 
the  irony  solution  supplied,  the  ponds  are  run  dry  and  cleared 
out  once  in  every  two  or  three  months.  Wind  and  rain  aid  the 
process  of  oxidation. 

(5)  AMALGAMATION.— Two  metals,  gold  and  silver,  are 
extracted  from  their  ores  by  amalgamation,  that  is  to  say,  by 
processes  based  upon  their  affinity  for  mercury ;  and  here  we  are 
once  more  on  the  borderland  between  mining  and  metallurgical 
practice.     In   the  case   of  silver   ores,  the   processes   are  often 
complex  and  require  the  precious  metal  to  be  brought  into  the 
state  of  chloride  before  amalgamation  is  possible ;  besides  which 
they  are  frequently  carried  on  at  works  which  do  not  belong  to  the 
mining  company.     I  therefore  consider  that  the  miner  would  be 
encroaching  upon  the  territory  of  his  neighbour  by  interfering  in 
this  instance,  whilst,  on  the  other  hand,  with  gold  the  process  is 
generally  simple,  and  the   ore  goes  straight  from  the  shaft  or 
adit  to  crushing  and  amalgamating  works  owned  by  the  same 
company  as  the  mine. 

The  amalgamation  of  gold  takes  place  by  mere  contact,  either 
when  the  particles  touch  the  mercury  as  they  slide  or  roll  along. 


DRESSING.  617 

in  a  current  of  water,  or  when  they  are  in  some  way  mechanically 
rubbed  against  it. 

An  instance  of  the  first  kind  of  action  has  already  been  given 
in  the  description  of  hydraulic  mining  in  Chapter  VI.,  and  another 
may  be  taken  from  the  ordinary  stamping  mill  of  most  gold 
mines  in  which  auriferous  quartz  is  being  treated.  The  pulp 
discharged  through  the  grates  of  the  mortar-box  is  allowed  to 
flow  over  an  inclined  table,  covered  with  a  sheet  of  copper  which 
has  been  amalgamated.  The  surface  of  the  copper  plate  is  first 
very  carefully  scoured,  then  cleaned  with  a  solution  of  cyanide  of 
potassium,  and  finally  rubbed  with  mercury  arid  a  little  sal- 
ammoniac.  The  bright  silvery  surface  is  then  capable  of  picking 
up  the  little  particles  of  gold  in  the  pulp  and  retaining  them  in 
the  form  of  a  coating  of  amalgam,  which  is  naturally  thickest 
where  the  pulp  first  comes  upon  the  table.  When  a  sufficient 
thickness  has  accumulated,  the  amalgam  is  scraped  off,  washed, 
mixed  with  a  little  fresh  quicksilver,  washed  with  water,  and 
finally  squeezed  through  canvas  or  chamois  leather.  The  hard 
amalgam  so  obtained  is  retorted. 

Various  devices  are  in  use  for  making  the  little  particles  of 
gold  turn  over  from  time  to  time  and  so  expose  fresh  surfaces  to 
the  quicksilver,  in  order  to  increase  the  chances  of  such  intimate 
contact  as  will  ensure  amalgamation.  Sometimes  steps  are  made 
in  the  tables,  giving  the  thin  stream  of  pulp  a  little  drop,  some- 
times the  tables  are  shaken,  whilst  in  the  Hungarian  mill  the 
pulp  flows  over  the  surface  of  a  bath  of  mercury,  the  surface  of 
which  is  lightly  skimmed  by  revolving  iron  knives. 

Amalgamation  will  not  take  place  unless  the  two  metals  are 
bright  and  clean ;  any  slight  film  upon  the  mercury,  such  as 
is  produced  by  grease  or  tarnish,  prevents  contact,  and  the  little 
particle  of  gold  rolls  or  slides  down  over  the  plate,  just  as  it 
would  do  on  a  plain  sheet  of  copper,  and  is  liable  to  escape. 
The  greatest  care  has  therefore  to  be  taken  to  keep  the 
amalgamated  plates  clean,  and  from  time  to  time  any  tarnish 
may  be  removed  by  brushing  them  with  a  solution  of  cyanide 
of  potassium.  Other  means  of  keeping  quicksilver  bright  are 
the  addition  of  a  little  sodium  amalgam,  or  the  production  of 
nascent  hydrogen  upon  the  surface  of  a  mercury  bath  by  the 
passage  of  a  current  of  electricity.  This  is  the  principle  of 
Molloy's  amalgamator,  and  that  invented  by  Chaster  and  Beck.  It 
is  evident  from  experiments,  when  the  mercury  covered  with  water 
is  connected  to  the  negative  pole  of  a  dynamo,  and  lead  plates 
forming  the  anode  are  connected  to  the  positive  pole,  that  the 
disengagement  of  hydrogen  does  keep  the  bath  constantly  bright 
and  lively,  and  fully  entitles  the  metal  to  its  familiar  name 
"  quicksilver."  Under  these  circumstances  it  takes  hold  of  the 
gold  more  readily,  but  the  process  does  not  appear  to  have  gone 
beyond  the  experimental  stage  at  present. 


618  ORE  AND  STONE-MINING. 

Considering  the  ease  with  which  amalgamation  is  impeded 
or  prevented  by  a  flimsy  coating  upon  the  mercury  or  upon  the 
gold,  it  is  not  surprising  that  rubbing  of  some  kind  should  have 
been  tried  in  order  to  brighten  the  surfaces  of  the  two  metals 
and  so  secure  perfect  contact.  It  seems  probable  that  when  gold 
was  worked  by  the  Romans  in  the  Alps,  the  precious  metal  was 
extracted  by  rubbing  the  ore  to  powder  with  water  and  mercury 
upon  slabs  of  gneiss  by  stone  mullers.  {Subsequently,  no  doubt,  the 
quern  was  pressed  into  the  service  of  the  gold-miner,  and  by  adding 
a  rude  horizontal  water-wheel  to  the  quern,  the  hardy  Piedmontese 
miners  developed  their  molinello,  or  small  mill,  by  means  of  which 
large  quantities  of  gold  have  been  obtained.  Proceeding  one  step 
further,  we  have  the  arrastra,  the  most  perfect  form  of  which  can 
probably  be  seen  in  Italy,  and  substituting  iron  and  steel  for 
stone  we  have  the  various  pans.  All  these  mills  perform  a  double 
service  ;  they  not  only  break  up  the  ore  and  set  free  the  minute 
particles  of  gold,  but  they  at  the  same  time  scour  the  gold, 
make  it  bright  and  rub  it  against  the  quicksilver.  Probably  in 
many  cases  the  gold  makes  a  streak  upon  the  bed,  just  as  it 
would  do  if  rubbed  upon  a  jeweller's  touchstone,  and  so  gives  a 
clean  bright  surface  with  which  the  mercury  at  once  amalgamates. 
The  mills  may  also  be  worked  as  concentrators,  for  if  a  stream  of 
water  is  run  through  them  while  they  are  being  driven  slowly,  the 
light  particles  are  carried  off,  and  the  heavy  metallic  sulphides  lie 
at  the  bottom  in  contact  with  the  mercury,  ready  to  give  up  the  gold 
they  contain  as  soon  as  they  are  crushed  fine  enough  to  liberate 
it.  The  heat  developed  by  the  friction  of  the  muller  is  consider- 
able and  may  assist  the  process  of  amalgamation,  and  indeed  it  may 
explain  how  it  is  possible  to  extract  80  percent,  of  the  gold  from 
ores  containing  10  to  20  per  cent,  of  iron  pyrites  by  simple  amal- 
gamation in  arrastras.  The  arrastra  is  a  more  suitable 
amalgamator  for  such  ores  than  the  copper  plate,  but  it  is  a 
slow  grinder  and  it  causes  a  large  loss  in  quicksilver  when  raw 
ore  is  treated  by  it.  Various  other  mills  are  used  for  the  same 
purpose. 

APPLICATION  OF  PROCESSES.— Having  now  passed 
in  review  the  various  mechanical,  physical,  and  chemical  processes 
which  are  employed  by  the  miner  in  preparing  his  minerals  for 
sale,  it  remains  to  say  a  few  words  upon  the  manner  in  which 
they  are  applied  in  different  cases.  Space  will  not  admit  more 
than  an  outline,  nor  is  it  necessary  in  a  general  text-book  to 
enter  deeply  into  details. 

For  the  sake  of  convenience  the  various  minerals  will  be  taken 
in  alphabetical  order. 

Amber. — The  lumps  are  separated  by  washing  from  the  enclos- 
ing sand,  and  are  sorted  according  to  colour  and  size.  The  small 
pieces  are  treated  in  a  steam  bath  at  a  temperature  of  150°  with 
certain  re-agents  in  order  to  remove  the  dark  rind,  and  the  clear 


DRESSING.  619 

kernels  which  remain  are   melted  up  together  and  sold  to  the 
varnish  merchants. 

Arsenic. — Arsenious  acid  is  obtained  by  roasting  and  sublima- 
tion. The  crude  arsenic  resulting  from  the  treatment  of  tin 
" whits"  is  usually  of  a  dirty  grey  colour  owing  to  the  ad- 
mixture of  solid  carbonaceous  particles  deposited  by  the  smoke ; 
it  is  spoken  of  as  "  arsenical  soot,"  and  is  sold  by  the  miner  to 
works  where  it  can  be  purified  by  being  re-sublimed. 

At  some  mines,  however,  which  yield  large  quantities  of  mis- 
pickel,  the  final  purification  is  performed  on  the  spot,  and  white 
sublimed  arsenic  and  arsenical  glass  are  prepared  by  re-sublima- 
tion, put  into  barrels  and  sent  out  into  commerce. 

Asbestos. — The  dressing  of  the  asbestos  (chrysolite)  of  Canada 
is  simply  a  process  of  cobbing — i.e.,  the  separation  of  the  valuable 
mineral  from  the  enclosing  serpentine  by  well-directed  blows  of 
the  hammer. 

Asphalt. — The  crude  Trinidad  pitch  is  purified  or  refined  on 
the  island  by  melting  it  in  iron  pans  and  allowing  the  earthy 
matter  to  fall  to  the  bottom.  In  France  the  process  is  some- 
what different :  the  crude  pitch  is  boiled  with  a  heavy  tar  oil 
obtained  from  the  distillation  of  shale,  in  the  proportion  of  9 
of  pitch  to  4  of  tar  oil.  The  30  per  cent,  of  water  in  the  pitch  is 
driven  off  and  a  small  amount  of  earthy  matter  is  deposited,  but 
the  refined  pitch,  consisting  of  the  two  ingredients  which  were 
mixed,  still  contains  a  large  percentage  of  clay. 

Bituminous  sandstone  *  is  made  to  yield  up  its  pitch  by  melting 
with  water.  The  sandstone  is  broken  up  into  lumps  about  3 
inches  across,  thrown  into  cauldrons  of  boiling  water,  and  stirred 
for  an  hour.  The  bitumen  melts  and  rises  to  the  top,  whilst 
the  sand  falls  to  the  bottom.  The  bitumen  is  skimmed  off,  though 
it  is  by  no  means  free  from  sand,  if  the  original  sandstone  was  fine- 
grained. It  is  then  re-melted  and  the  sand  allowed  to  sink; 
the  liquid  bitumen  is  drawn  off  and  allowed  to  cool  in  moulds, 
but  the  sandy  deposit  at  the  bottom  still  contains  a  good  deal  of 
pitch  which  cannot  profitably  be  separated. 

The  treatment  of  the  bituminous  limestone  of  Seyssel  has 
already  been  described  in  the  general  part  of  this  chapter. 

Barytes. — The  principal  processes  in  preparing  barytes  for 
the  market  are  drying  and  grinding. 

The  barytes  coming  from  the  mine  is  washed  and  picked,  and 
pieces  intermixed  with  rock  are  cleaned  by  cobbing.  The  lumps 
are  dried  upon  a  tiled  floor  heated  by  flues  underneath,  and  are 
then  crushed,  either  by  rolls  or  an  edge-runner,  to  a  coarse 
powder,  which  is  twice  ground  in  mills  like  flour- mills.  French 
burr  stones  are  preferred.  The  second  grinding  yields  a  powder 
as  fine  as  flour,  which  is  put  up  into  barrels  ready  for  sale. 

*  Malo,  UAsplialte,  Paris,  1888,  p.  68. 


62o  ORE  AND  STONE-MINING. 

Iron-stained  barytes  is  "  bleached "  by  acid,  as  already  ex- 
plained. 

Borax. — The  earth  obtained  at  the  borax  la.ke,  California,  is 
ground,  and  then  dissolved  in  water  brought  to  the  boiling 
point  in  large  iron  vats  by  injecting  steam.  The  contents  are 
allowed  to  settle,  and  the  clear  solution,  containing  the  carbonate, 
sulphate,  chloride,  and  borate  of  sodium,  is  drawn  off  into  pans 
and  allowed  to  cool.  The  borax  is  the  first  to  crystallise  out,  and 
the  crystals  are  collected  and  sold,  or  are  re-dissolved  ;  this  second 
solution  furnishes,  on  crystallising,  the  refined  borax  of  com- 
merce.* 

Boric  Acid. — The  solution  of  boric  acid,  obtained  in  Tus- 
cany by  passing  natural  steam-puffs  (soffioni)  through  water,  is 
evaporated  either  by  the  heat  of  some  of  these  soffioni,  or 
artificially,  until  the  gypsum  and  other  impurities  separate; 
the  liquid  is  drawn  off  and  the  acid  is  allowed  to  crystallise 
out. 

Carbonic  Acid. — If  not  at  once  piped  off  to  white  lead  or  soda 
works,  carbonic  acid  is  compressed  and  sold  in  the  liquid  state. 

Clay. — Common  clays  are  used  on  the  spot,  and  made  into 
bricks,  tiles,  or  drain-pipes.  The  potter's  clay  of  Devonshire 
is  sent  away  in  cubical  lumps  just  as  they  come  from  the  pit, 
but  the  china  clay  is  obtained  by  a  true  dressing  process.  The 
stream  of  water  running  down  the  side  of  the  openwork,  and 
carrying  with  it  all  the  ingredients  of  the  decomposed  granite,  is 
led  into  a  pit  where  the  coarse  particles  of  quartz  settle,t  whilst  the 
clayey  water  is  conducted  into  long  channels  in  which  fine  sand  and 
mica  are  deposited  gradually.  Lastly,  the  milky  stream  reaches 
circular  pits,  20  to  40  feet  in  diameter,  and  6  to  20  feet  deep, 
drops  its  kaolin,  and  passes  off  as  almost  clean  water.  The 
creamy  deposit  is  dried  in  the  manner  already  described  (Fig.  676), 
and  the  china  clay  of  commerce  is  the  result. 

Fuller's  earth  is  also  a  clay  which  has  to  be  dressed  before  being 
sent  into  the  market.  The  processes  to  which  it  is  usually  sub- 
jected are  drying,  sifting,  and  grinding. 

The  clay  coming  from  the  pits  is  dried  in  kilns  (Fig.  677)  and 
sifted  by  hand  to  take  out  the  fine,  if  the  customer  insists  upon 
having  nothing  but  lumps.  The  dry  lumps  are  put  up  into  sacks, 
and  the  small  is  sifted  again.  The  very  fine,  below  J  inch,  is 
thrown  away,  and  the  coarser  part  is  ground  to  fine  flour  in  an 
Askham  mill,  and  so  sold. 

In  addition  to  this  dry  dressing,  some  of  the  clay  is  ground  in 
an  edge-runner,  run  into  settling  tanks,  and  dried  much  in  the 
same  way  as  china  clay. 

*  Napier  Hake,  "  An  Account  of  a  Borax  Lake  in  California,"  Jour.  Soc. 
Chem.  Jnd.,  vol.  viii.,  1889,  p.  856;  E.  L.  Fleming,  "Borax,"  Chem.  Neics, 
vol.  Ixiii.,  1891,  p.  74. 

f  Collins,  Ihe  Hensbqrrow  Granite  District,  Truro,  1878,  p.  18. 


DRESSING.  621 

Copper  Ore.* — The  ores  of  copper  are  so  different  that  no 
general  scheme  of  treatment  suitable  to  all  of  them  can  be  pre- 
scribed. Thus,  for  instance,  the  copper  shale  of  Mansfeld  is 
merely  picked  at  the  mine  before  going  to  the  smelting  works, 
which  receive  an  ore  containing  only  2  to  3  per  cent,  of  metal.  At 
the  Lake  Superior  mines  concentration  by  water  can  be  carried 
to  such  a  pitch  that  the  "  barrel  copper "  leaving  the  dressing 
establishments  often  has  more  than  70  per  cent,  of  metal. 

Hand-picking  is  generally  an  important  part  of  the  dressing 
when  the  ore  consists  largely  of  a  mineral  like  chalcopyrite, 
because  it  is  easily  crushed  to  powder  liable  to  be  carried  away  by 
water  in  washing.  At  the  Rio  Tinto  mines  t  the  following  are 
the  principal  varieties  separated  by  picking : 

a.  Rich  ore  with  5  cr  6  per  cent,  of  copper,  which  is  smelted  on  the 

spot. 

b.  Lump  ore  with  2  to  3  per  cent  of  copper,  which  is  exported. 

c.  Lump  ore  with  2  per  cent,  of  copper,  which  is  burnt  in  heaps  on 

the  spot. 

d.  Fine  ore,  which  is  added  to   the  burnt  ore,  so  that  its  copper 

may  be  gradually  rendered  soluble. 

e.  Quartzose  ore,  which  is  retained  for  the  furnaces. 

When  copper  pyrites  occurs  coarsely  intermixed  with  quartz  and 
other  earthy  minerals,  the  dressing  usually  begins  with  hand-picking 
and  crushing  by  rolls  ;  the  coarser  grains  are  jigged,  and  the  finest 
particles  are  cleaned  and  rendered  rich  enough  for  sale,  by  buddies, 
frames,  revolving  tables,  or  endless  belts.  Intermediate  products 
made  up  of  ore  and  waste  have  to  be  re-crushed  before  a  complete 
separation  is  possible. 

At  the  Lake  Superior  mines,  where  the  mineral  is  native 
copper,  the  treatment  is  different.  The  rock  from  the  mine  is 
stamped  by  huge  Ball  or  Leavitt  stamps  until  it  will  pass  through 
holes  of  T3F-  inch,  and  the  copper-bearing  stream  is  delivered 
into  upward  current  separators,  which  make  five  classes;  the 
four  coarsest  sizes  are  treated  on  Collom  jigs,  and  the  fifth  upon 
revolving  tables. 

Diamonds. — The  dressing  of  the  diamond-bearing  rock  of 
South  Africa  J  may  be  divided  into  the  following  separate 
operations : 

a.  Natural  disintegration,  under  atmospheric  agencies,  aided  by 
watering,  rolling  and  harrowing. 

*  Egleston,  "  Copper  Dressing  in  Lake  Superior,"  Metallurgical  JReview, 
New  York,  vol.  ii.,  1878. 

Henderson,  "  On  the  Methods  generally  adopted  in  Cornwall  in  Dressing 
Tin  and  Copper  Ores,"  Proc.  Inst.  C.  E.,  vol.  xvii.,  1857-58,  p.  106. 

Rathbone,  "  On  Copper  Mining  in  the  Lake  Superior  District,"  Proc. 
Inst.  Meek,  fing.,  1887,  p.  86. 

t  Collins,  "  On  the  Geology  of  the  Rio  Tinto  Mines,"  Q.  J.  Geol.  Soc.t  vol. 
xli.,  1883,  p.  256. 

£  De  Beers  Consolidated  Mines,  Limited,  Second  Annual  Report,  for  the 
Year  ending  %ist  March  1890,  p.  19. 


622  ORE  AND  STONE-MINING. 

b.  Screening  in  a  revolving  screen,  with  holes  i  inch  by  i  inch, 
or  i  inch  by  T  J,  which  take  out  coarse  lumps  ;  these  are  returned 
to  the  depositing  floors  to  undergo  the  weathering  process  a  little 
longer. 

c.  Washing  the  fine  in  rotary  pans,  which  separate  clean  gravel 
from  the  fine  sand  and  mud;  the  latter  flow  into  another  similar 
washer,  where  the  process  is  repeated  in  case  any  diamonds  should 
have  escaped  in  the  overflow  from  the  first. 

d.  Screening  the  clean  gravel  through  a  cylindrical  sieve,  with 
round  holes  varying  from  J  inch  to  f  inch  in  diameter,  making 
in  all  five  sizes.    The  largest  grains  discarded  by  the  sieve  are 
picked  at  once. 

e.  Treatment  in  a  "  pulsator,"  which  is  simply  a  jig  with  con- 
tinuous feed  and  discharge  like  the  Hartz  jigs.  The  bed  is  formed 
of   leaden    bullets.     A   concentrate,   containing   the    diamonds, 
passes  through   the  bed,  and  refuse  goes  over  the  edge  of   the 

jig- 

f.  Picking  out  the  diamonds  by  hand,  first  by  white  men  when 
the  gravel  is  wet,  and  then  by  native  convicts  when  it  is  dry. 
The  operation  of  picking  is  repeated  as  often  as  enough  diamonds 
are  found  to  repay  the  cost  of  the  labour. 

Flint  and  Chert. — Flints  are  trimmed  into  square-faced 
lumps  for  building  purposes,  or  are  split  and  trimmed  into 
gun-flints.  Chert  is  trimmed  by  hammering  into  blocks  for  use 
in  the  potteries. 

Gold.  — The  precious  metal  may  be  extracted  from  simple  sand 
and  gravel  by  mere  washing,  or  by  washing  combined  with  amal- 
gamation. Hydraulic  mining  affords  an  example  of  the  latter 
method.  When  the  gold  is  enclosed  in  hard  rock  such  as  quartz, 
or  occurs  in  a  hard  tightly  cemented  conglomerate,  the  auriferous 
stone  has  to  be  crushed  in  order  to  set  the  metal  free. 

The  crushing  is  most  often  effected  by  a  stonebreaker,  followed 
by  stamps,  and  the  pulp  is  run  over  amalgamated  copper  plates. 
Mercury  is  often  added  in  the  battery  so  as  to  catch  the  coarse 
gold  at  once.  The  amalgam  scraped  off  the  plates  and  taken  out 
of  the  battery-box  is  cleaned  and  retorted,  giving  spongy  gold, 
which  is  melted  in  crucibles  and  cast  into  bars.  If  the  ore 
contains  much  pyrites  or  other  heavy  metallic  sulphides,  the  stuff 
leaving  the  amalgamated  plates  is  taken  to  a  dressing  machine  of 
some  kind,  such  as  a  Frue-vanner,  which  furnishes  a  concentrate 
consisting  largely  of  metallic  sulphides,  more  commonly  known  to 
miners  by  their  older  name  of  "  sulphurets."  These  are  sure  to 
contain  gold,  and  they  are  further  treated  in  various  ways :  by 
direct  amalgamation  in  pans,  which  means  a  still  finer  grinding, 
to  liberate  more  of  the  fine  particles  of  gold,  by  smelting,  by 
chlorination,  or  by  the  cyanide  process. 

Gold  is  also  extracted  by  grinding  up  the  ore  in  mills  or  arras- 
tras  with  water  and  a  little  mercury.  Excellent  results  have 


DRESSING.  623 

been  obtained  in  Italy  by  this  method,  even  with  highly  pyritic 
ores. 

It  is  very  necessary  that  the  miner  should  recollect  that  gold 
does  not  always  exist  in  the  same  state  in  the  ore,  and  that  the 
value  of  the  ore  depends  not  only  upon  the  amount  of  metal  in 
it,  but  also  upon  the  ease  with  which  it  is  extracted.  A  mere 
assay  gives  information  upon  the  first  point  only.  It  tells  how 
much  gold  there  is  per  ton,  but  it  does  not  say  whether  the 
metal  is  in  the  native  state,  or  whether  it  is  combined  with  some 
other  element  which  may  render  extraction  by  amalgamation 
quite  impossible.  Even  when  the  gold  is  all  native,  the  size  of 
the  particles  varies  considerably,  and  they  may  or  may  not  be 
wrapped  up  in  iron  pyrites  or  other  metallic  sulphides.  Con- 
sequently it  is  futile  to  suppose  that  all  gold  ores  can  be  treated 
by  one  and  the  same  method. 

Graphite. — The  graphite  of  Ceylon  is  first  picked  at  the 
mine,  and  then  despatched  to  Colombo  to  undergo  the  processes  of 
cobbing,  picking,  and  screening.  Men  and  women,  using  a  tool 
like  a  little  axe,  chip  off  the  waste  material  from  the  lumps,  and 
sift  the  small  fragments  upon  slightly  inclined  screens  made  of 
sheet-iron.  They  also  clean  the  lumps  with  brushes  made  of 
cocoa-nut  husks.  In  this  manner  four  different  kinds  of  graphite 
are  produced — viz.,  "  large  lumps,"  pieces  about  as  big  as  the  fist 
or  larger  ;  "  ordinary  lumps,"  about  the  size  of  walnuts  ;  "  chips," 
about  the  size  of  grains  of  wheat ;  and  "  dust,"  which  includes 
everything  smaller.  The  graphite  is  now  ready  to  be  barrelled 
for  export. 

One  mode  of  concentrating  certain  kinds  of  graphite  has  been 
mentioned  as  an  instance  of  a  method  depending  upon  differences 
of  friability ;  but  in  addition  to  these  dry  processes,  graphite  is 
also  dressed  by  the  aid  of  water.  In  Moravia  and  Bohemia 
graphite  is  found  in  gneiss,  and  may  be  intermixed  with  lime- 
stone, quartz,  iron  pyrites,  garnets  and  hornblende.  Rock  of  this 
kind  is  pulverised  by  grinding  in  mills,  or  by  stamping,  and  the 
pulp  is  made  to  flow  into  rectangular  wooden  boxes  in  which  the 
coarser  particles  and  part  of  the  rock  and  pyrites  are  deposited. 
The  graphite-bearing  water  passes  on  into  a  number  of  long 
rectangular  wooden  troughs  (tyes,  strips,  or  strakes,  Cornwall),  in 
which  the  graphite  deposits  itself  gradually,  whilst  clean  water 
flows  out  of  the  last  trough.  The  first  trough  has  the  worst 
graphite,  and  the  last  the  best  quality  of  the  mineral.  The 
deposit  is  dug  out,  pressed  in  filter  presses,  and  the  resulting 
cakes  are  dried  in  stoves.* 

Gypsum. — The  preparation  of  gypsum  for  the  market  resolves 

*  Andree,  "  Der  osterreichische  und  bayerische  Graphitbergbau,"  B.  u. 
li.  Z.<  1890,  p.  269. 

Schauenstein,  DenHuch  des  osterreicliischen  Berg-  und  Hiittenwesens, 
Vienna,  1873,  p.  116. 


624  ORE  A^D  STONE-MINING. 

itself  into  picking,  breaking,  burning  and  grinding  ;  or  where  the 
gypsum  is  required  for  other  purposes  than  cement  making,  the 
burning  or  baking  is  omitted. 

In  Sussex  the  waggons  coming  from  the  mine  are  tipped  on  to  a 
floor,  the  large  lumps  are  broken  up  with  a  sledge  hammer,  and  any 
pieces  much  mixed  with  worthless  rock  are  picked  out  as  useless. 
The  remainder  is  sent  to  a  stonebreaker,  and  the  broken  lumps  go 
either  to  a  baking  oven  to  be  made  into  plaster,  to  a  burning 
oven  if  Parian  cement  is  required,  or  to  a  grinding  apparatus  if  the 
gypsum  is  sold  to  manure  merchants. 

After  burning  or  baking,  the  product  is  ground,  first  by  toothed 
rolls  and  then  under  edge-runners.  It  is  now  taken  up  by  an 
elevator,  put  through  a  tine  revolving  screen,  and  is  drawn  off 
into  sacks. 

Iron. — With  a  substance  of  small  intrinsic  value  like  iron  ore, 
the  methods  of  dressing  must  be  inexpensive  if  they  are  to  be 
commercially  profitable  ;  and  at  the  present  time  it  may  be  said 
that  most  of  the  iron  of  commerce  is  obtained  from  ores  which 
go  direct  to  the  smelter  without  any  preparation  beyond  picking 
out  refuse  underground.  A  few  instances  of  calcination  have 
already  been  noted,  and  also  the  separation  of  fine  ore  by  a 
sieve.  Iron  ore  is  sometimes  washed  in  order  to  get  rid  of 
adherent  clay,  and  at  the  mines  of  North  Lancashire  some  of 
the  haematite,  mixed  with  clay  and  siliceous  matter,  is  made  fit 
for  the  blast  furnace  by  crushing  and  jigging.* 

The  same  line  of  treatment  is  pursued  in  the  dressing  works  of 
the  Chateaugay  Ore  and  Iron  Company,  at  Lyon  Mountain,  N.Y. 
The  mine  produces  magnetic  iron  ore,  the  richer  parts  of  which 
are  picked  out,  whilst  the  leaner  parts,  consisting  of  grains  of 
magnetite  disseminated  through  gneiss,  go  to  the  mills  .for  con- 
centration. This  mixed  ore  is  crushed  by  Blake  breakers,  and  after 
screening  is  treated  in  Conkling  jigs.f 

Haematite  for  fettling  puddling  furnaces  is  ground  under  edge- 
runners,  and  that  which  is  used  for  making  castings  malleable  is 
carefully  screened.  Special  qualities  are  picked  out  for  these 
purposes. 

In  this  country  the  supply  of  magnetic  iron  ore  is  insignificant, 
and  consequently  we  cannot  show  examples  of  concentrating  by 
the  aid  of  magnetism,  such  as  may  be  found  in  Sweden  and  the 
United  States,  where  this  method  is  occupying  much  attention, 
as  may  be  inferred  from  the  descriptions  of  magnetic  separators 
just  given. 

Lead.J — A  few  mines  produce  lumps  of  galena  so  pure  that 

*  J.  G.  Lawn. 

t  Euttmann,  "  Concentrating  Magnetite  with  the  Conkling  Jig  at  Lyon 
Mountain,  N.Y.,"  Trans.  Amer.  Inst.  M.E.,  vol.  xvi.,  1888,  p.  609  ;  and 
E.  M.  J.,  vol  xlvi.,  1888,  p.  870. 

J  For  details  consult  Bellom,  "  Etat  actuel  de  la  preparation  mecanique 


DRESSING.  625 

they  merely  require  washing  in  order  to  be  ready  for  sale  to  the 
smelter  or  the  potter. 

Much  of  the  lead  ore  from  veins  is  dressed  by  crushing, 
sizing  and  jigging ;  the  particles  under  i  mm.,  or  at  all  events 
under  \  mm.,  are  treated  by  revolving  tables,  percussion  tables, 
endless  belts,  or  buddies. 

The  crushing  is  done  first  by  a  stonebreaker  and  then  by  rolls. 
Blende  is  often  associated  with  galena,  but  owing  to  the  difference 
in  their  specific  gravities,  a  separation  can  be  made  by  the 
appliances  just  mentioned.  Products  obtained  from  the  jigs 
consisting  of  mixed  minerals  have  to  be  re-crushed,  and  then 
treated  once  more  by  machinery  similar  to  that  used  for  the 
original  ore.* 

The  soft  lead -bearing  sandstone  of  Mechernich  f  crumbles  to 
pieces  so  easily,  that  by  the  time  it  reaches  the  dressing  establish- 
ment, after  having  fallen  down  in  the  underground  chambers  and 
dropped  through  shoots  into  the  waggons,  most  of  it  is  in  a  fit  state 
for  the  concentrating  machinery.  The  works  are  specially  designed 
for  treating  very  large  quantities  of  poor  ore  consisting  almost 
entirely  of  galena  and  quartz  sand ;  their  main  feature  is  the  use 
of  the  siphon  separator  (p.  578),  by  which  a  very  large  pro- 
portion of  the  stuff  is  at  once  concentrated  into  clean  concretions 
(Knotten)  containing  about  22  per  cent,  of  lead.  This  concentrate 
goes  to  another  establishment,  where  it  is  stamped  and  passed 
through  siphon  separators,  jigs,  revolving  tables  and  round 
buddies,  in  order  to  separate  lead  ore  fib  for  the  furnaces. 

Manganese. — The  only  preparation  of  the  Welsh  manganese 
ore  is  separating  the  fine  ore  under  J  inch,  by  sifting  in  the  mine, 
and  picking  out  of  any  pieces  of  waste  or  very  poor  rock. 

The  Devonshire  ore,  which  consisted  largely  of  psilomelane, 
was  washed  and  picked,  and  the  "  smalls  "  were  jigged.  Some  of 
the  large  ore  was  crushed ;  the  coarse  part  was  jigged,  and  the 
fine  cleaned  in  buddies. 

Mica.  | — The  rough  blocks  obtained  from  the  mine  are  cleaved 
by  means  of  steel  wedges  into  sheets  |  inch  or  less  in  thickness, 
and  these  are  cut  by  the  "  scriber "  into  the  shapes  required  for 
stove  windows.  There  are  a  very  large  number  of  patterns, 
ranging  in  size  from  ixitoSxio  inches.  The  cutting  is  done 

des  minerals  dans  la  Saxe,  le  Hartz  et  la  Prusse  Rhenane,''  Annales  des 
Mines,  ser.  8,  vol.  xx.,  1891,  p.  5. 

Munroe,  "  The  New  Dressing  Works  of  St.  Joseph  Lead  Company,  at 
Bonne  Terre,  Missouri,"  Trans.  Amer.  Inst.  M.E.,  vol.  xvii.,  1888,  p.  659. 

*  Sopwith,  "  The  Dressing  of  Lead  Ores,"  Proc.  Inst.  C.  E.,  vol.  xxx., 
1869-70,  p.  1 06. 

f  Der  Bergbau  und  Hiitteribetrieb  des  Jlechernicher  Bergwerks-Actien- 
Vereins,  Cologne,  1886,  p.  10,  and  Tables  II.  and  III.  ;  and  B.  u.  h.  Z., 
1886,  p.  476. 

£  Phillips,  "  Mica  Mining  in  North  Carolina,"  Eng,  Min.  Jour.,vc].  xlvi., 
1888,  p.  418. 

2   R 


626  ORE  AND  STONE-MINING. 

with  a  knife  along  the  edges  of  a  template  made  of  iron  or  tin- 
plate.  The  blocks  of  crude  mica  yield  from  ^  to  J  of  cut  mica 
fit  for  the  market.  The  refuse  scraps  are  now  ground  up  into 
fine  powder  and  used  in  the  manufacture  of  wall-paper,  tinsel, 
hair-powder,  and  lubricants.* 

Nitrate  of  Soda. — The  process  of  extracting  the  commercial 
nitrate  from  the  crude  caliche  has  already  been  sufficiently 
described,  in  speaking  of  the  preparation  of  minerals  by  solution 
and  crystallisation. 

Ochre. — Native  ochre  is  ground  under  an  edge-runner  with 
water,  and  the  product  is  run  into  settling  pits.  Coarse  sand 
settles  first,  and  further  away  the  sediment  consists  of  fine  ochre, 
which  is  dug  out  and  dried.  The  ochre  deposited  by  the  water 
coming  from  cementation  pits  has  simply  to  be  dug  up  and  dried. 

The  native  umber  of  Devonshire  is  stamped  and  ground  under 
edge-runners ;  the  umber  suspended  in  water  is  pumped  up  and 
allowed  to  settle  in  tanks  until  it  can  be  dug  out.  It  is  then 
dried  in  the  same  way  as  china  clay.t 

Ozokerite. — Some  of  the  mineral  is  brought  up  in  the  form 
of  fairly  clean  lumps  which  have  been  picked  out  underground 
and  put  into  sacks.  These,  together  with  similar  pieces  picked 
out  above  ground  and  scraped  free  from  dirt,  are  melted  in  large 
semi-spherical  open  cast-iron  pans  and  boiled.  When  allowed  to 
settle,  the  earthy  matter  falls  to  the  bottom  and  clean  ozokerite 
floats  on  the  top.  This  is  ladled  out  into  cylindrical  moulds,  and 
on  cooling  furnishes  the  large  loaves  of  commercial  ozokerite. 
Water  is  added  to  the  earthy  residues  at  the  bottom  of  the  pans, 
and  the  whole  brought  to  the  boiling-point.  Ozokerite  rises  to 
the  top  and  is  skimmed  off,  whilst  the  residues  remaining  at  the 
bottom,  which  still  contain  some  10  per  cent,  of  wax,  are  sold  to 
dealers  who  extract  it  by  means  of  benzine. 

The  small  stuff  coming  from  the  mine  which  will  go  through 
a  grating  with  bars  2  inches  apart  is  put  into  a  tub  of  water ;  the 
wax  rises,  is  skimmed  off  with  a  sieve  and  purified  by  melting, 
and  the  earthy  residues  are  sold,  or  are  stocked  until  the  miner 
puts  up  plant  for  extraction  by  benzine. 

Phosphate  of  Lime. — The  varieties  of  this  mineral  are  so 
numerous,  from  the  hard  compact  apatite  of  Canada  to  the  pulveru- 
lent mineral  of  the  Somme  district,  that  the  modes  of  treatment 
must  necessarily  be  extremely  different ;  sometimes  also  the  mineral 
is  sold  finely  ground  and  put  up  in  sacks  ready  for  the  farmer,  in 
other  cases  the  miner  satisfies  himself  with  removing  all  waste, 
and  leaves  to  other  persons  such  processes  as  milling  or  manu- 
facture into  superphosphate. 

*  Nitze,  "  Ground  Mica  Industry  in  North  Carolina,"  Eng.  Min.  Jour., 
vol.  liv.,  1892,  p.  292. 

t  Frecheville,  "  The  Umber  Deposits  at  Ashburton,"  Ivans.  JR.  Geol. 
Soc.,  Cornwall,''  vol.  ix.  p.  219. 


DRESSING.  627 

As  a  rule,  the  treatment  may  be  summed  up  as  drying  and 
grinding,  often  preceded  by  a  preliminary  washing.  For  instance, 
the  phosphate  of  the  Somme  is  dried  first  upon  iron-plated  floors, 
and  then  in  a  Ruelle  stove  or  a  revolving  calciner.  This  prepares 
it  for  grinding.  The  first  grinding  is  done  between  two  vertical 
stones,  and  all  that  is  fine  enough  is  drawn  out  by  an  exhaust 
fan  j  the  portion  which  is  too  coarse  to  be  sucked  up  by  the 
current  of  air  passes  into  a  mill  with  horizontal  stones  and  is  re- 
ground.  After  being  put  into  sacks  it  is  ready  for  the  manure 
merchant,  or  for  the  farmer  if  he  applies  it  to  his  land  direct. 

The  nodules  of  the  South  Carolina  phosphate  are  freed  from 
the  sand  and  clay  by  a  mechanical  washer,  in  the  form  of  a  helix 
revolving  i  n  a  trough.  The  material  is  fed  in  at  the  lower  end 
and  is  gradually  screwed  up  to  the  other  against  a  strong  stream 
of  water.  The  water  carries  away  the  waste,  and  clean  lumps  are 
delivered  at  the  other  end.  The  washed  nodules  are  dried  in. 
kilns  and  are  then  ready  for  export.* 

Potassium  Salts. — The  two  principal  potassium  salts  obtained 
by  mining  are  carnallite  and  kainite.  Simple  grinding  is  often  the 
only  preparation  before  sale,  but  in  some  cases,  as  explained  on 
page  608,  the  carnallite  undergoes  a  complicated  treatment  by 
solution  and  crystallisation,  for  the  purpose  of  extracting  chloride 
of  potassium  and  utilising  the  by-products  obtained  in  these 
processes. 

Quicksilver. — The  great  intrinsic  value  of  quicksilver  ore 
enables  hand-picking  to  be  carried  further  than  would  be 
compatible  with  a  mineral  of  little  worth.  At  Idriaf  the  loss  of 
mercury  was  so  great  under  the  old  system  of  wet  dressing, 
in  spite  of  the  high  specific  gravity  of  cinnabar,  that  this, 
method  was  given  up  some  fifty  years  ago.  Nowadays,  the 
preparation  for  the  smelting  is  done  solely  by  crushing,  sizing,  and 
hand-picking.  The  stuff  broken  in  the  mine  is  separated  under- 
ground into  waste,  poor  ore  and  rich  ore.  The  first  is  left  in  the 
workings,  and  the  two  kinds  of  ore  are  tipped  separately  on  to  a 
grating  with  holes  of  4  inches  (100  mm.)  across.  The  coarse 
lumps  are  crushed  by  Blake's  stonebreakers,  and  the  broken  ore 
which  is  too  big  to  pass  through  holes  of  £  inch  (20  mm.)  is 
hand-picked ;  the  portions  so  separated  are  made  ready  for  the 
smelting  works  by  further  crushing.  When  poor  ore  is  being 
treated,  waste  can  be  picked  out  and  thrown  away  at  once.  The 
stuff  passing  through  the  20  mm.  mesh  is  crushed  by  rolls  and 
sent  to  the  smelting  works. 

The  "smalls"  which  passed  the  100  mm.  grating  are  screened 
on  a  2-inch  (50  mm.)  sieve;  the  coarse  goes  to  the  stonebreaker 
and  the  fine  to  screens  of  different  sizes.  All  that  is  over  £  inch 

*  Benedict,  "  Mining,  Washing,  and  Calcining  South  Carolina  Phosphate,'" 
Eng.  Min.  Jour.,  vol.  liii.,  1892,  p.  349. 

t  Das  k.  k.  Quecksilberwerk  zu  Idria  in  Krain,  Vienna,  1881,  p.  19. 


628  ORE  AND  STONE-MINING. 

(20  mm.)  is  picked,  and  some  waste  taken  out ;  what  is  under 
this  size  is  passed  through  the  rolls  and  so  made  fit  for  the 
furnaces. 

Salt. — The  mode  of  making  a  saleable  product  from  brine  has 
already  been  described ;  but  it  must  not  be  forgotten  that  brine 
itself  is  sold  as  such  to  works  which  make  alkali  by  the  Solvay 
process. 

Some  rock-salt  is  prepared  for  the  market  by  crushing.  At 
one  of  the  Cheshire  mines  there  are  three  pairs  of  crushing  rolls 
one  above  the  other,  the  first  pair  coarsely  fluted,  the  second  pair 
fluted,  but  less  coarsely,  and  the  third  or  lowest  pair  smooth.  The 
rolls  are  from  18  inches  to  2  feet  in  diameter  and  2j  feet  long. 
The  rolls  of  another  crusher  are  made  up  of  toothed  rings 
threaded  upon  shafts,  and  so  arranged  that  the  teeth  of  one  roll 
fit  between  two  of  the  rings  of  the  opposite  roll.  Some  of  the  salt 
is  also  ground  by  a  disintegrator. 

Silver. — The  ores  of  silver  may  be  divided  into  two  classes : 
silver  ores  proper  and  argentiferous  lead  and  copper  ores. 

Many  of  the  silver  minerals  are  very  friable,  and  are  liable  to  be 
carried  off  with  the  refuse,  if  subjected  to  the  ordinary  wet  dress- 
ing processes ;  the  preparation  of  such  ores  at  the  mine  is  gene- 
rally limited  to  crushing,  picking,  and  cobbing.  The  miner  then 
relegates  to  others  the  task  of  extracting  the  precious  metal  by 
methods  based  upon  its  affinity  for  quicksilver  or  molten  lead,  or 
upon  the  leaching  properties  of  hyposulphite  of  soda. 

Argentiferous  lead  and  copper  ores  are  concentrated  by  the 
processes  in  vogue  for  the  baser  metals ;  but  if  the  proportion  of 
silver  is  large,  a  greater  amount  of  labour  may  be  expended  upon 
hand-picking  and  cobbing  than  would  be  permissible  with  ores  of 
lead  and  copper  alone. 

Slate. — Two  articles  of  commerce  are  made  at  the  quarries : 
roofing  slates  and  thick  slabs  used  for  cisterns,  billiard-tables, 
and  tombstones.  The  slate  arrives  at  the  surface  in  the  form 
of  large  blocks,  often  weighing  two  tons  or  more.  These  are 
divided  by  splitting  into  slabs  about  3  inches  thick,  which  go  to  the 
sawing  tables.  The  circular  saws  cut  up  the  slabs  into  pieces 
suitable  for  the  operation  of  fine  splitting ;  by  the  careful  and 
dexterous  use  of  his  wedge  and  mallet,  the  quarryman  is  able  to 
split  the  slab  into  thin  sheets,  which  at  Festiniog  often  do  not 
exceed  ^  inch  in  thickness.  These  have  to  be  trimmed,  generally 
into  a  rectangular  form.  Though  this  operation  can  be  and 
often  is  performed  by  hand,  it  is  more  common  to  use  some 
kind  of  knife  worked  by  machinery  (Fig.  639).  The  slates  are 
then  sorted  by  hand  according  to  their  quality.  The  slabs  are 
first  split  out  of  blocks,  and  are  finished  by  being  sawn  into  shape 
and  planed  smooth  by  machinery. 

Stone. — It  is  impossible  in  a  general  treatise  to  enter  into  any 
details  concerning  the  preparation  of  stone  at  mines  and  open- 


DRESSING.  629 

works.  Some  stone  is  shaped  by  hammering,  into  paving  blocks 
or  "  setts  " ;  much  is  crushed  by  stonebreakers  and  sold  as  road- 
metal  after  removal  of  the  fine  by  screening ;  freestone  is  sawn  so 
as  to  suit  the  builder ;  flags  are  obtained  by  splitting  micaceous 
sandstone  along  the  planes  of  bedding  and  trimming  the  edges, 
and,  lastly,  gunflints  are  made  from  the  well-known  nodules  by 
the  dexterous  chipping  of  the  "  knapper." 

Sulphur. — This  element  is  obtained  from  the  rock,  which 
contains  it  in  the  native  state,  by  simple  liquation  in  a  kiln  of 
some  kind,  intermittent  (calcarone)  (Fig.  677)  or  continuous  (Gill's 
furnace),  by  liquation  in  steam-heated  cylinders,  or  by  distillation 
in  iron  retorts ;  this  last  process,  which  was  at  one  time  practised 
with  rich  ore  in  the  Romagna.  is  now  almost  entirely  abandoned. 

Tin.* — The  tin  ore  obtained  from  veins  usually  contains 
the  cassiterite  so  finely  disseminated  through  the  stone,  that  a 
considerable  amount  of  comminution  is  required  before  the  valu- 
able grains  are  thoroughly  liberated,  and  so  rendered  capable  of 
being  separated  by  washing.  In  Cornwall  the  first  process  is  a 
preliminary  crushing  by  a  Blake's  stonebreaker,  followed  by 
stamping  until  the  pulp  will  pass  through  a  fine  grate.  The  pulp 
is  led  into  round  buddies  in  order  to  produce  a  first  concentrate, 
containing  not  only  all  the  cassiterite,  but  also  the  iron  pyrites, 
mispickel  and  other  metallic  sulphides  with  which  it  is  so  often 
associated.  By  repeating  the  operation  of  huddling,  a  concentrate 
is  obtained,  which  is  subjected  to  "  tossing  and  packing ;'  in  order 
finally  to  prepare  it  for  the  furnace.  This  first  concentrate,  known 
in  Cornwall  by  the  name  of  whits,  is  dried  upon  the  top  of  the 
calciner  and  then  roasted  in  the  manner  already  described.  After 
roasting,  the  buddling  is  repeated,  and,  lastly,  the  tossing  and 
packing,  with  the  result  that  clean  tin  ore  with  65  to  70  per  cent, 
of  metal  can  be  put  away  in  bins,  ready  to  be  done  up  in  sacks 
and  despatched  to  the  smelting  works.  In  some  cases  the  ore  is 
not  contaminated  with  sulphides,  and  no  roasting  is  required. 

The  tin-bearing  sand  and  gravel,  which  have  furnished  and  are 
still  furnishing  such  a  large  proportion  of  the  world's  supply  of  the 
metal,  can  be  treated  in  a  speedier  fashion.  The  wash-dirt  is 
simply  shovelled  or  hoed  against  a  stream  of  water  in  a  ditch  or 
trough  -,  the  light  waste  is  washed  away,  and  the  heavy  pebbles 
and  clean  grains  of  cassiterite  are  left  at  the  head.  This  is  the 
method  usually  employed  in  the  East. 

The  tin-gravel  worked  at  Restronguet  Creek,t  near  Truro,  was 
washed  with  water  in  order  to  separate  adherent  clay,  and  then 

*  Ferguson,  "  On  the  Mechanical  Appliances  used  for  dressing  Tin  and 
Copper  Ores  in  Cornwall,"  Proc.  Imt.  Mech.  Eng.,  1873,  P-  I19  >  Henderson, 
"On  the  Methods  generally  adopted  in  Cornwall  in  dressing  Tin  and 
Copper  Ores,"  Proc.  Inst.  C.E.,  vol.  xvii.,  1857-58,  p.  106. 

f  Taylor,  "  Description  of  the  Tin  Stream  Works  in  Restronguet  Creek, 
near  Truro,"  Proc.  Imt.  Mech.  Eng.,  1873,  p.  161. 


630  OEE  AND  STONE-MINING. 

passed  to  a  revolving  sieve.  The  fine  stuff  was  jigged,  and  finally 
cleaned  by  a  propeller-knife  huddle ;  the  large  pebbles  were 
picked  over,  and  those  containing  tin  were  stamped  and  treated 
like  vein  rock. 

At  Mount  Bischoff,*  in  Tasmania,  the  process  of  dressing  may 
be  briefly  summed  up  as  follows :  Comminution  by  stamps,  and 
extraction  of  the  tin  ore  from  the  pulp  by  jigs  and  revolving 
tables. 

Zinc. — Calamine  has  sometimes  to  be  washed,  in  order  to  rid 
it  of  clay,  before  it  is  crushed  and  jigged  like  lead  ore. 

Blende  is  dressed  in  the  same  way  as  lead  ore,  and  is  often  ob- 
tained from  one  compartment  or  portion  of  a  dressing  machine, 
whilst  galena  is  being  discharged  from  another. 

LOSS  IN  DRESSING. 

The  loss  in  dressing  is  frequently  very  great,  and  proofs  of  this 
fact  constantly  come  under  one's  notice.  Old  heaps  of  mining  refuse 
left  by  former  workers  may  be  seen  yielding  an  abundant  harvest 
to  a  later  generation,  and  even  with  the  machinery  of  to-day  the 
extraction  is  far  from  perfect.  For  instance,  in  the  year  1891  no 
less  than  879  tons  of  dressed  tin  ore,  worth  ,£33,704,  were  ex- 
tracted from  the  muddy  water  discharged  into  the  "  Red  River  " 
and  its  tributaries  by  some  of  the  large  tin  mines  near  Camborne 
and  Redruth. 

The  loss  is  due  to  several  causes.  First  comes  imperfect 
severance  of  the  valuable  mineral  from  the  worthless  constituents 
of  the  ore  during  the  crushing  process  r}  this  is  unavoidable  if  the 
mineral  occurs  in  the  state  of  very  minute  particles.  Secondly, 
the  thickness  of  the  dirty  water  escaping  from  the  machines, 
which  impedes  the  subsidence  of  the  fine  grains ;  thirdly,  want  of 
care  on  the  part  of  the  persons  placed  in  charge  of  the  machinery. 
In  addition  to  these  causes,  which  are  general,  special  reasons  ac- 
counting for  loss  will  be  found  with  certain  minerals :  the 
amalgamation  of  gold  is  prevented  by  grease,  by  any  coating  or 
film  upon  it  which  impedes  close  contact  with  the  mercury,  by  the 
presence  in  the  ore  of  substances  which  have  an  injurious  effect 
upon  the  mercury,  "  sickening  "  it,  or  in  other  words  depriving  it 
of  its  natural  activity.  Again,  if  the  mineral  is  flaky,  it  will  not 
fall  so  easily  in  water  as  if  the  particles  more  nearly  approached 
a  spherical  shape. 

The  actual  loss  has  been  very  carefully  ascertained  in  some 
cases,  though  less  attention  is  paid  to  exact  determinations  than 
the  subject  deserves.  M.  Bellomf  cites  three  cases  of  loss  at  mines 
producing  argentiferous  galena  and  blende. 

The  ore  delivered  to  the  Himmelfahrt  Works,  near  Freiberg, 

*  Kayser,    "  Advantages   of   Ore-dressing    by    Automatic    Machinery/' 
Trans.  Min.  Assoc.  and  Inst.  Cornwall,  vol.  ii.,  1888,  p.  51. 
f   Op.  cit.,  p.  624. 


DRESSING.  631 

contains  2§  per  cent,  of  lead,  0*275  percent,  of  zinc,  and  7*3  ozs. 
of  silver  per  metric  ton  (23  grammes  per  100  kil.),  besides  a 
little  copper,  J  per  cent,  of  arsenic,  and  5  per  cent,  of  sulphur. 
The  galena  is  dressed  to  85  per  cent,  of  lead  and  96  ozs.  of  silver 
(3°°  grammes  per  100  kil.),  the  blende  to  40  per  cent,  of  zinc  and 
9-6  ozs.  of  silver  (30  grammes  per  100  kil.),  the  pyritic  minerals 
to  40  per  cent,  of  sulphur  and  16  ozs.  of  silver  (50  grammes 
of  silver  per  100  kil.).  The  losses  are  found  to  be  21  per  cent,  of 
the  silver,  38  per  cent,  of  the  lead,  and  60  per  cent,  of  the 
sulphur. 

At  the  Churprinz  Works,  also  near  Freiberg,  the  raw  ore  con- 
tains 3  per  cent,  of  lead,  and  3  ozs.  of  silver  per  metric  ton  (9^ 
grammes  per  100  kil.),  and  a  dressed  product  is  prepared  with 
70  per  cent,  of  lead  and  16  ozs.  of  silver  per  ton  (50  grammes 
of  silver  per  100  kil.).  The  loss  in  dressing  is  2 2 '8  per  cent,  of 
the  silver  and  14*9  per  cent,  of  the  lead. 

The  ore  treated  at  Ems  contains  4  per  cent,  of  lead,  2  J  per  cent, 
of  zinc,  and  i"j  ozs.  of  silver  per  metric  ton  (5*4  grammes  per  100 
kil.),  but  the  enrichment  by  washing  is  not  carried  so  far  as  at  the 
other  works.  The  galena  is  dressed  to  36  per  cent,  of  lead  and 
9- 6  ozs.  of  silver  per  metric  ton  (30  grammes  per  100  kil.),  and 
the  blende,  which  is  not  argentiferous,  to  44 \  per  cent,  of  zinc.  The 
losses  are  8  per  cent,  of  the  silver,  6  per  cent,  of  the  lead,  and  34 
per  cent,  of  the  zinc. 

It  is  to  be  regretted  that  so  many  dressing  establishments  in 
this  country  are  working  entirely  in  the  dark,  and  are,  therefore, 
utterly  ignorant  of  the  losses  that  are  going  on. 

At  few  places  in  the  world  is  the  loss  more  carefully  studied 
than  at  the  mines  of  the  Pestarena  Company  in  Northern  Italy, 
for  a  sample  is  taken  from  every  waggon  of  crushed  ore  before  it 
goes  to  the  mills.  The  quantity  of  gold  in  the  ore  treated  can, 
therefore,  be  ascertained  with  great  accuracy,  and  by  comparing 
this  amount  with  the  quantity  extracted,  it  is  found  that  about 
one-fifth  escapes  amalgamation  and  is  lost ;  the  ores  sometimes 
contain  10  to  20  per  cent,  of  pyrites. 

Another  kind  of  loss  which  requires  to  be  ascertained  is  the 
purely  mechanical  waste  in  preparing  stone  for  the  market.  In 
the  case  of  slate  it  is  very  large,  for  the  blocks  brought  from 
the  workings  into  the  mills  frequently  yield  only  25  per  cent,  of 
roofing  material.  As  the  amount  of  rubbish  produced  in  getting 
out  the  blocks  is  also  considerable,  the  quantity  of  saleable  slate  is 
often  only  one-twelfth  of  the  actual  rock  excavated. 

Seeing  that  the  proportion  of  waste  material,  whether  in  ore 
mines  or  stone  mines,  is  usually  large,  it  behoves  the  miner  in 
laying  out  his  dressing  establishment,  to  make  provision  for  the 
disposal  of  great  quantities  of  refuse. 


632  ORE  AND  STONE-MINING. 

SAMPLING. 

The  miner  may  have  to  sample  the  produce  of  his  mine  tor  a 
variety  of  reasons.  Sometimes  sampling  is  necessary  in  order  to 
ascertain  the  amount  of  money  due  to  the  workmen ;  it  is  indis- 
pensable when  the  loss  in  dressing  has  to  be  ascertained,  and, 
lastly,  the  miner,  after  preparing  his  various  products  for  sale, 
requires  samples  for  possible  purchasers. 

Sampling  may  be  done  by  hand  or  by  machinery.  Four  methods 
of  hand-sampling  may  be  mentioned : 

HAND-SAMPLING. — i.  Sampling  by  taking  out  small 
lots. — If  the  mineral  is  in  coarse  lumps  and  the  valuable  ingredient 
irregularly  distributed,  picking  up  a  few  stones  here  and  there 
is  not  likely  to  yield  a  very  correct  sample ;  but,  on  the  other 
hand,  if  the  mineral  is  already  crushed,  and  if  the  small  lot 
is  taken  regularly,  say  for  instance  every  tenth  shovelful,  it  is 
possible  to  obtain  great  accuracy.  Thus  at  the  Pestarena  mines 
the  gold  ore  before  being  milled  is  crushed  by  rolls  until  it  will 
pass  a  sieve  with  three  holes  to  the  inch ;  and  from  each  waggon 
of  crushed  ore  about  2  kilos,  are  taken  by  a  tin  measure.  The 
load  is  spread  out  horizontally  with  the  hand  and  a  tin  measure 
is  filled  from  this  flat  surface  and  thrown  into  a  tub.  Each 
waggon  is  weighed,  and  the  2  kil.  represent  about  o^th  °^  ^he 
load.  At  the  end  of  the  day  the  tubful  is  taken  as  the  sample  of 
the  stuff  sent  to  the  mills.  From  this  large  sample  a  small  one 
is  prepared  by  the  process  of  quartering,  which  will  be  described 
immediately. 

This  method  of  sampling  will  also  suffice  in  the  case  of  an  ore 
of  small  intrinsic  value,  such  as  an  iron  ore,  consisting  in  the 
main  of  one  mineral. 

2.  Trenching. — In  order  that  this  method  of  sampling  may 
be  accurate,  it  is  necessary  that  the  mineral  be  well  mixed,  and 
where  a  valuable  ore  is  concerned,  great  care  is  expended  upon 
the  operation.  It  may  happen  that  there  are  a  number  of  small 
heaps  of  dressed  ore,  each  produced  by  a  different  gang  of  men, 
which  have  to  be  mixed  before  being  sold  in  one  lot.  The  stuff 
from  the  first  heap  is  spread  out  evenly  on  a  smooth  flat  floor. 
Layer  after  layer  is  added  from  the  other  small  heaps  until 
a  large  square  or  rectangular  pile  is  obtained  made  up  of 
horizontal  strata.  The  mixing  is  now  carried  out  by  taking 
off  a  slice  from  the  side  of  the  heap  with  a  shovel,  so  as  to 
cut  through  all  the  layers ;  the  stuff  is  tossed  on  to  the  floor 
and  spread  over  a  large  area,  and  the  thorough  intermingling 
is  aided  by  a  boy  who  stirs  it  as  it  falls.  The  original  heap  is 
cut  away  slice  after  slice,  and  gradually,  at  the  side  of  it,  another 
heap  is  formed  with  the  particles  thoroughly  mixed,  which  is  ready 
for  the  operation  of  trenching  ;  it  may  be,  for  instance,  10  ft.  wide 
by  15  ft.  long,  and  18  inches  high.  If  the  operation  of  turning 


DRESSING.  633 

over  and  mixing  was  carried  on  along  the  long  side  of  the  rectangle, 
a  couple  of  trenches  are  dug  across  the  heap  at  right  angles  to 
this  direction,  or  in  other  words  parallel  to  the  short  sides.  The 
trenches  are  cut  down  to  the  bottom,  and  after  they  have  been 
carefully  swept  out,  the  sampler  slices  off  small  portions  of  the 
sides  with  his  shovel.  All  that  he  cuts  down  in  this  way  is 
shovelled  into  hand-barrows,  and  constitutes  the  large  sample, 
which  has  simply  to  be  reduced  in  bulk  by  quartering. 

With  coarsely  broken  mineral  the  part  shovelled  out  in  making 
the  trench  is  often  taken  as  a  first  sample  and  not  the  thin  slices 
from  the  sides,  as  is  done  with  fine  material. 

The  two  trenches  are  sometimes  cut  at  right  angles  to  one 
another,  forming  an  ordinary  cross,  or  along  the  diagonals,  forming 
a  St.  Andrew's  cross,  and  the  heaps  are  often  round  instead  of 
being  rectangular. 

(3)  Quartering. — Quartering  is  a  process  of  dividing  a  given 
lot  of  mineral  again  and  again  until  a  sufficiently  small  sample 
remains.  The  mineral  is  made  into  a  conical  heap  by  letting  each 

FIG.  695.  FIG.  696. 


shovelful  which  is  emptied  fall  down  evenly  over  the  apex  of  the 
cone.  The  apex  is  pressed  down,  and  the  heap  is  spread  out  till 
it  forms  a  low  truncated  cone,  a  cross  is  marked  upon  it  with 
the  point  of  the  shovel,  and  the  two  opposite  quarters,  say 

1  and  3  (Fig.  695),   are   scraped   aside   and   discarded,   leaving 

2  and    4,    or    one-half    of    the    original    sample.       These   two 
quarters,   2   and  4,   are   mixed   by   hand,   a   new   conical   heap 
made  and  the  quartering  repeated.     The  next  time  the  sampler 
will  retain  the  quarters  i  and  3,  and  put  aside  2  and  4.     If  the 
mineral  is  not  fine,  it  should  be  crushed  once  or  twice  and  put 
through  a  finer  sieve  during  the  process.     In  this  manner  a  large 
sample  is  reduced  sufficiently  in  bulk,  to  give  the  miner  a  small 
lot  which  is  a  fair  average  of  the  whole. 

(4)  Sampling  Shovel.* — This  implement  is  designed  for 
the  purpose  of  obtaining  an  average  sample  of  a  heap  of 
mineral  by  merely  shovelling  it  over.  It  consists  of  a  flat 
rectangular  plate  with  vertical  sides  (Fig.  696),  and  two  vertical 
partitions  which  enclose  a  central  compartment  occupying  one 
fourth  of  its  area.  This  compartment  is  closed  at  the  back  or 
handle  end,  whilst  the  rest  of  the  plate  is  open.  After  the 

*  Eng.  Hin.  Jour.,  vol.  li.,  1891,  p.  718. 


634  ORE  AND  STONE-MINING. 

shovel  has  been  filled  by  a  thrust  into  the  heap  of  finely  crushed 
mineral,  it  is  easy  to  discharge  the  outer  three-fourths  of  its  con- 
tents over  the  back  end,  and  then,  turning  it  over,  to  deposit 
the  central  quarter  in  a  separate  place  as  the  sample. 

MACHINE  SAMPLING.— While  we  have  generally  been 
content  on  this  side  of  the  Atlantic  to  go  on  with  the  old- 
fashioned  methods  of  hand-sampling,  much  ingenuity  has  been 
displayed  in  the  United  States  with  the  object  of  producing 
machinery  for  doing  the  work,  and  thereby  saving  time  and 
labour,  to  say  nothing  of  furnishing  more  accurate  results. 

According  to  the  principle  upon  which  they  work,  sampling 
machines  may  at  once  be  divided  into  two  great  classes  :  * 

(1)  Machines  which  take  part  of  the  stream  of  material  for  the  whole 

of  the  time. 

(2)  Machines  which  take  the  whole  of  the  stream  of  material  for  part 

of  the  time. 

(i)  In  the  former  class  a  spout  or  opening  of  some  kind  is 
arranged  so  as  to  divert  part  of  the  stream  of  ore,  coming  from  a 
crusher  for  instance,  into  a  separate  receptacle. 

Two  samplers  used  some  years  ago  in  Colorado  belong  to  the 
first  class.  One  of  them  is  a  hollow  cone  with  four  large  holes  ; 
the  stream  of  crushed  ore  falls  upon  the  apex,  and  the  particles 
spreading  themselves  out  slide  down  over  the  steep  surface.  The 
path  of  some  of  the  particles  leads  them  to  the  holes,  where  they 
drop  through,  forming  a  sample  of  the  whole.  The  size  of  the 
holes  can  be  arranged  so  as  to  extract  a  given  percentage  of  the 
total  quantity,  and  this  first  sample  can  be  reduced  in  bulk  by  a 
second  passage  over  the  cone. 

In  the  other  the  desired  result  is  obtained  by  letting  the  ore 
fall  on  to  three  inclined  shelves  one  above  the  other,  f  Each  shelf 
has  openings  which  allow  a  'portion  of  the  ore  to  drop  through. 
The  ore  dropping  through  the  first  shelf  falls  upon  the  second, 
which  in  its  turn  eliminates  part  and  lets  the  remainder  drop  on 
to  the  third  shelf,  where  the  process  is  repeated.  The  portion 
which  has  passed  through  the  three  shelves  constitutes  the 
sample. 

Clarkson's  Rapid  Sampler,  an  English  machine  (Fig.  697), 
consists  of  a  revolving  conical  hopper,  supplied  with  the  mineral, 
which  runs  through  a  hole  in  the  bottom,  and  drops  on  to  the 
apex  of  a  cone.  In  the  path  of  the  falling  stream  of  mineral, 
now  converted  into  a  hollow  rotating  cylinder,  there  are  two 
segmental  spouts,  which  intercept  any  desired  proportion  of  it, 
and  so  furnish  two  independent  samples.  The  size  of  the  spout 
determines  the  percentage  which  is  diverted  as  a  sample. 

*  Bridgman,  "A  new  System  of  Ore-sampling,"  Trans.  Amer.  Inst.M.E., 
vol.  xx.,  1891,  p.  416. 

t  Egleston,  "  Sampling  Ores  in  Colorado,"  Engineering,  vol.  xxii.,  1876, 
P.  495- 


DRESSING. 


635 


(2)  In  the  second  class  the  whole  stream  is  deflected  at  regular 
intervals,  and  this  method  has  the  advantage  of  ensuring  the 
proper  proportion  between  the  fine  and  the  coarse,  which  cannot 
always  be  attained  by  the  fixed  spout ;  where  the  constituent 
minerals  vary  in  friability  the  accuracy  of  the  result  must  de- 
pend upon  this  proportion  being  strictly  maintained.  In 
Brunton's  *  sampler  the  stream  of  ore  falling  down  a  vertical 
trough  is  diverted  to  one  side  or  the  other  by  a  partition  which 
is  moved  backwards  and  forwards  by  very  simple  machinery. 
There  are  means  of  regulating  the  proportion  of  the  time  during 
which  the  stream  is  being  turned  into  the  side  for  receiving  the 
sample. 

Bridgman's  ore-sampler  f  has  the  advantage  of  supplying  two 


FIG.  697. 


FIG.  698. 


FIG.  699. 


absolutely  independent  samples,  and  it  divides  them  as  often  as 
desirable  previous  to  a  recrushing. 

The  work  is  begun  by  a  horizontal  revolving  wheel  formed  of 
two  concentric  rings,  with  vertical  partitions  dividing  it  into 
eight  segments  (Fig.  698).  Underneath  this  first  "  apportioner," 
as  it  is  called  by  the  inventor,  comes  a  second  one  (Fig.  699)  ;  it  is 
a  funnel  with  openings,  a,  b,  c,  d,  on  the  side,  and  is  made  to 
revolve  in  the  opposite  direction  to  the  first.  It  is  succeeded  by 
a  third  of  similar  construction.  The  ore  is  fed  from  a  pipe  on  to 
some  point  of  the  first  apportioner,  and  each  segment  necessarily 
receives  one-eighth  of  the  stream ;  segment  No.  i  has  a  spout 
which  travels  round  the  outer  circumference  of  the  apportioner 
below  it,  passing  over  the  holes  a  and  6,  whilst  the  spout  of  No. 

*  "A  new  System  of  Ore-sampling,"  Trans.  Amer.  lust.  M.E.,  vol.  xiii., 
1885,  p.  639.  t  Op.  tit. 


636  GEE  AND  STONE-MINING. 

5  takes  an  inner  path,  including  the  holes  c  and  d  ;  the  spouts 
of  2,  3,  4,  6,  7,  and  8,  deliver  their  ore  into  the  centre  C.  One- 
eighth  of  the  stream  from  the  spout  of  No.  i  drops  through  a  and 
another  eighth  through  b  ;  the  rest  falls  on  to  the  parts  A  and 
B  of  the  funnel  and  is  discharged  into  the  centre.  Likewise 
the  original  one-eighth  from  spout  5  drops  in  part  through 
c  and  d,  and  in  part  on  to  A  and  B.  The  portion  passing 
down  through  a  and  5,  or  through  c  and  d,  is  therefore  one- 
quarter  of  one-eighth,  or  one-thirty-second,  of  the  original  bulk. 
The  third  apportioner  again  collects  one-quarter  and  discards 
three-quarters  of  each  of  the  two  samples  coming  to  it,  so  that  the 
final  samples  furnished  by  the  machine  are  both  T^g-  of  the  total. 
These  first  samples  are  then  recrushed  and  passed  through 
another  machine  of  similar  construction  but  giving  only  one 
sample. 

Mr.  Bridgman  has  likewise  devised  a  small  sampler  for  use  in 
the  laboratory. 


637 


CHAPTER  XIV. 
PRINCIPLES  OF  EMPLOYMENT  OF  MINING  LABOUK. 

Modes  of  payment,  according  to  time,  measure  or  weight ;  tribute 
systems. 

PERSONS  employed  at  mines  may  have  their  wages  reckoned  in  one 
of  four  different  ways  : 

1.  By  time. 

2.  ,,     measure  or  weight. 

3.  „     a  combination  of  Nos.  i  and  2  systems. 

4.  .,     value  of  the  mineral  obtained. 

(i)  The  first  system  is  largely  adopted  for  surface  labour, 
such  as  is  required  on  the  dressing  floors.  Enginemen,  stokers, 
millmen,  smiths  and  carpenters  are  likewise  paid  so  much  a 
day  of  a  stated  number  of  hours.  A  time-book  is  kept,  and 
the  wages  are  reckoned  up  at  the  end  of  the  week,  fortnight, 
or  month  by  a  simple  multiplication  sum.  For  true  mining 
or  quarrying — that  is  to  say,  for  excavating  valuable  mineral 
and  removing  worthless  rock — this  system  is  far  less  common 
than  the  other  three.  There  are  objections  to  it  both  on 
the  part  of  mine-owners  and  on  the  part  of  many  of  the  men. 
The  owner  has  to  employ  more  foremen  to  look  after  the  work, 
and  an  amount  of  supervision  which  would  be  sufficient  at  the 
surface  is  utterly  inadequate  below  ground,  because  the  working 
places  are  not  within  sight  from  any  one  point,  and  can  only  be 
reached  by  traversing  low  and  tortuous  passages,  or  by  climbing 
down  and  up  ladders.  The  men,  too,  in  many  cases  prefer  to  be 
paid  on  some  system  which  gives  the  skilled  and  steady  miner 
the  advantage  of  deriving  some  profit  from  his  exertions,  over  and 
above  the  average  daily  wage  he  would  receive  if  time  were  the 
only  standard  for  good  and  bad  workers  alike. 

In  rare  cases  persons  are  hired  for  the  day  only ;  this  is  done 
sometimes  at  the  ozokerite  mines  at  Boryslaw,  where  the  agent 
picks  out  in  the  morning  as  many  men  as  he  wants  from  those 
assembled  at  the  top  of  the  pit. 

In  new  countries  or  districts,  payment  of  miners  by  the  day 
may  be  necessary  at  first,  because  the  work  is  so  strange  that 
the  men  are  afraid  to  enter  into  contracts,  which  would  appear 
perfectly  reasonable  and  satisfactory  to  them  if  they  had  been 


638 


ORE  AND  STONE-MINING. 


used  from  boyhood  to  this  system  of  arranging  earnings. 
After  the  more  enterprising  men  have  learnt  by  actual  practice 
what  they  are  capable  of  doing,  they  drop  into  the  contract 
system,  and  in  due  course  of  time  the  others  follow  them. 

(2)  Much  of  the  work  at  mines  is  regulated  by  a  system  of 
piecework  of  some  kind,  calculated  by  measure  or  by  weight. 
In  Cornwall  and  some  other  districts,  work  done  in  this  fashion 
is  known  as  "tutwork."  No  doubt  the  original  meaning  of  the 
word  was  "  dead  work,"  from  the  German  word  "  todt,"  because 
preliminary  and  unremunerative  work  was  paid  for  in  this  manner ; 
nowadays  the  meaning  of  the  term  is  extended,  and  it  includes 
the  excavation  of  ore.  In  driving  a  level,  for  instance,  the  man- 
ager specifies  that  the  height  shall  be  7  feet  and  the  width  5  feet, 
and  agrees  to  pay  so  many  pounds  for  every  yard  or  fathom  of 
advance.  As  a  rule  the  mine-owner  provides  all  the  necessary 
materials,  and  deducts  their  value  at  the  end  of  the  contract. 
An  example  or  two  will  make  the  system  plain. 

THE   ADVENTUKE   MINING  COMPANY,    LIMITED. 
Tutwork  pay  for  the  Month  of  May  1886. 


JOHN  SMITH  AND  PAETNERS.    6  Men. 

Amount. 

Fms.    Ft. 

In. 

Price. 

£ 

s. 

d. 

Sinking      .         ,         .         .         .42 

o 

I40/- 

30 

6 

8 

Stoping      .....20 

0 

6o/- 

6 

0 

0 

Putting  in  9  stulls 

10  1- 

4 

10 

0 

40 

,6 

8 

£ 

«. 

d. 

DEDUCTIONS. 

Cash  on  account          .... 

21 

0 

O 

Candles,  72  Ibs.  at  4^.         .        ^ 

I 

4 

O 

Powder,  100  Ibs.  at  40?. 

I 

13 

4 

Dynamite,  20  Ibs.  at  is.  8d. 

I 

*3 

4 

Fuse,  34  coils,  at  $d.  .        «        . 

H 

2 

Hilts,  at  6d.         .               ... 

Shovels,  at  25.      .                 .        . 

Smith's  cost         .                 .... 

Powder  cans,  at  is. 

Doctor  and  club          ... 

18 

0 

27 

2 

10 

Balance          .        .        ,        .       £ 

13 

13 

TO 

PRINCIPLES  OF  EMPLOYMENT.  639 

The  meaning  of  this  pay-bill  is  that  John  Smith  and  five  other 
men  took  a  contract  to  sink  a  certain  shaft  at  ^7  per  fathom, 
and  to  stope  part  of  the  lode  at  ^3  per  fathom.  They  sank  the 
shaft  4  fathoms  2  feet,  and  stoped  away  2  fathoms ;  in  addition 
to  this  they  put  in  some  timber,  a  matter  not  included  in  the 
original  contract,  and  for  which  they  are  credited  with  £4.  IQS. 
extra.  The  gross  balance  due  to  them  is  therefore  £40  i6s.  Sd., 
against  which  they  are  debited  with  the  cost  of  the  candles  and 
explosives  supplied  to  them,  and  with  their  subscriptions  for 
medical  attendance  and  accident  club.  While  the  contract 
was  running  they  received  £2 1  on  account,  so  that  on  the  pay- 
day they  took  up  a  balance  of  ^13  13$.  iod.  In  a  contract 
of  this  kind  the  leading  man,  John  Smith,  is  known  as  the 
"  taker." 

In  stoping  a  vein,  the  price  is  calculated  per  square  fathom  of 
advance  for  its  whole  width ;  thus  if  a  lode  is  4  feet  wide,  stoping 
i  fathom  of  ground  means  the  removal  of  a  block  6  ft.  high 
6  ft.  long  and  4  feet  wide  ;  in  other  words,  144  cubic  feet.  In  wide 
lodes  the  men  are  sometimes  paid  per  cubic  fathom  excavated.  At 
one  British  lead  mine,  where  the  lode  sometimes  measures  several 
fathoms  from  wall  to  wall,  a  standard  price  is  arranged  for  a 
width  of  6  feet,  and  where  the  stopes  are  wider  than  this  the 
men  are  paid  extra.  In  order  to  prevent  loss  of  ore  through 
carelessness,  the  men  are  paid  a  premium  of  155.  a  ton  for  all  the 
lead  ore  they  save. 

Another  example  (p.  640)  gives  an  instance  of  "  tutwork  "  wages 
calculated  by  weight.  It  is  copied  from  the  figures  on  the  back  of 
the  little  envelope  in  which  the  money  is  handed  to  the  "taker  "  on 
the  pay-day.  The  account  shows  that  Richard  Williams  and  his 
six  partners  excavated  120  tons  9  cwt.  of  tin  ore  ("tinstuff") 
at  6s.  per  ton,  and  were  credited  with  ^36  2s.  Sd.  Against  this 
they  had  to  pay ^£5  43.  ^d.  for  materials  (candles,  explosives,  &c.), 
75.  for  doctor,  55.  $d.  for  club  and  is.  gd.  for  barber,*  leaving  a 
balance  of  ,£30  45.  ^d.  to  be  divided  among  them,  that  is  to  say 
£j  is.  yd.  per  man  per  week. 

A  third  basis  of  payment  is  the  number  of  inches  bored  in  the 
shift.  This  plan  was  in  vogue  in  stoping  the  wide  lead-lodes  in  the 
Upper  Hartz  some  years  ago ;  it  necessitated  careful  supervision, 
for  otherwise  the  men  bored  their  holes  in  the  softest  places  they 
could  find,  or  in  positions  enabling  them  to  wield  their  hammers 
with  the  greatest  ease,  without  any  thought  for  the  work  required 
from  the  shots.  A  foreman  came  round  at  the  beginning  of  the 
shift,  and  pointed  out  how  the  holes  were  to  be  placed  ;  in  the 
middle  of  the  shift  he  returned,  measured  the  depths  bored,  and 
then  charged  and  fired  the  holes  while  the  men  rested.  The 
positions  for  fresh  holes  were  then  indicated,  and  at  the  end  of 

*  The  item  "barber,"  a  charge  of  yL  per  man  per  month,  still  remains 
in  a  few  of  the  oldest  mines  in  Cornwall.  The  barber  attends  at  the 
mines  on  Saturdays. 


640 


ORE  AND  STONE-MINING. 


the  shift  the  depths  were  measured  and  booked,  previous  to  the 
charging  and  blasting.  The  price  paid  was  i  M.  38  Pf.  per 
metre  of  hole  bored  upwards,  and  i  M.  13  Pf.  per  metre  of  hole 
bored  downwards ;  in  the  latter  case  the  men  could  put  water  in 
the  holes,  which  keeps  the  finely  powdered  rock  in  suspension  and 
allows  the  cutting  edge  of  the  tool  to  do  better  execution. 

The  men  working  away  the  great  pyrites  deposit  at  Rammels- 
berg  in  the  Lower  Hartz  by  means  of  boring  machinery  are  paid 

WHEAL  CHANCE. 

EICHAED  WILLIAMS  AND   PAETNERS. 

Pay  for  4  weeks  ending  27th  May. 
Paid  loth  June  1893. 


TUTWORK. 

Fms. 

Ft. 

Ins. 

Price. 

£ 

8. 

rf. 

Driving 

Sinking 

Kising 

Tons. 

Cwts. 

Stoping 
Stems         .         . 

1  2O 

9 

61- 

36 

2 

8 

Subsist           .... 

£ 

s. 

d. 

Materials       .... 

5 

4 

4 

Doctor,  Club,  and  Barber      .   i 

14 

0 

5 

18 

4 

I 

Balance        •        •        •        •  '    j6 

30 

'  4          4 

per  metre  of  hole  bored,  as  this  method  is  more  convenient  than 
measuring  up  the  amount  of  "ground"  removed  in  wide  work- 
ings and  paying  per  cubic  metre.  The  latter  system,  however,  is 
adopted  in  driving  levels  and  sinking  shafts  where  the  dimensions 
of  the  excavation  are  regular. 

In  removing  overburden,  where  everything  has  to  be  sent  away 
indiscriminately,  payment  per  cubic  yard  excavated  is  common, 
just  as  it  is  in  making  railway  cuttings ;  this  system  is  adopted 
with  the  men  who  uncover  the  iron  ore  in  Northamptonshire 
(Fig.  324),  whilst  those  employed  in  getting  the  ore  are  paid  so 
much  per  ton  put  into  the  waggons. 


PRINCIPLES  OF  EMPLOYMENT.  641 

(3)  The  combination  of  the  two  methods,  payment  by  time 
and  payment  by  measure  or  weight  of  some  kind,  may  be  adopted 
when  men  are  too  inexperienced  or  too  timid  to  take  contracts 
depending   solely  upon   results.     This   plan   has  been  found  to 
answer  at  a  pyrites  mine  in  North  Wales,  where  the  mineral  is 
got  by  the  aid  of  rock  drills  worked   by   compressed   air.     The 
miners  receive  a  fixed  wage  of  a  pound  per  week  and  a  premium 
of  a  penny  per  foot  for  every  foot  bored  over  12  feet  per  day  of 
eight   hours.     The   company    finds  the   machines  and  all   tools 
The  mine  is  worked  in  three  shifts  of  eight  hours  each ;  in  two  of 
them  the  men  are  merely  boring,  and  in  the  third  shift  a  set  of 
blasters  come  round  to  charge  and  fire  the  holes.    Of  course,  as  in 
the  Hartz,  the  position  of  the  holes  is  planned  by  the  foreman. 
By  working  in  this  way  the  men  generally  make  from  3$.  to  45.  a 
week  extra  pay,  for  they  are  able  to  bore  40  or  50  feet  a  week 
more  than  the  standard  task.     The  ore  is  fairly  uniform  in  hard- 
ness, for  otherwise  it  would  be  impossible  to  maintain  a  single 
tariff  for  the  whole  of  the  mine.     This  system  has  been  advan- 
tageous both  to  the  men  and  to  the  company.     Previous   to   its 
introduction  the  men  were  all  on  one  dead   level,  and  had  no 
interest  in  exerting  themselves ;  they  each  got  their  £i  a  week 
by  doing  the  minimum  amount  which  enabled  them  to  escape  a 
scolding  from  the  foreman,  whilst  now  the  man  who  works  hard 
feels  that  he  will  get  some  recompense  for  his  extra  exertions. 
The  company  benefits  by  having  an  increased  output  at  a  smaller 
cost  per  ton,  without  any  extra  plant. 

(4)  We  now  come  to  the  fourth  or  last  system — viz.,  payment 
by  value  of  the  product.     This  system  has  had  its  home  in  the 
south-west  of  England  for  many  years,  and  has  been  transplanted 
by  the  ubiquitous  Cornishman  to  many  other  ore-mining  districts. 
In  Cornwall  it  is  known  as  working  on  "  tribute." 

Under  the  tribute  system  a  gang  of  men  agree  to  hand  over 
to  the  mining  company  all  the  ore  they  raise,  on  condition  that 
they  receive  a  certain  proportion  of  its  value.  Thus,  supposing 
that  the  tribute  is  ^,  or  55.  in  the^i,  and  that  a  couple  of  men 
produce  marketable  copper  ore  worth  ^£50,  their  share  will  be 
j£>S°  •*•  i  °r  j£12  i  os.,  less  the  cost  of  the  materials  they  have 
been  supplied  with,  and  all  the  expenses  for  winding,  dressing, 
sampling,  &c.  In  other  words,  the  tributer  may  be  said  to  take  a 
sublease  of  part  of  the  mine  and  pay  a  royalty,  in  this  case  of  J 
or  75  per  cent,  for  the  permission  to  work  accorded  to  him.  But 
it  must  be  recollected  that  the  mining  company  renders  the  place 
accessible  to  him,  keeps  it  drained  and  ventilated,  and  supplies 
him  with  machinery  for  raising  his  ore  to  the  surface  and  dressing 
it,  which  he  could  not  provide.  The  tributer  is  therefore  a 
person  who  can  speculate  upon  the  value  of  the  ore  in  a  certain 
small  working  area,  without  having  any  capital  beyond  his  brain 
and  his  muscle. 

2  S 


642 


ORE  AND  STONE-MINING. 


The  precise  nature  of  this  mode  of  payment  will  be  best  under- 
stood by  an  actual  example. 

John  Jones  and  Partners, 

WHEAL  CHANCE. 

Pay  for  4  weeks  ending  27th  May. 

Paid  loth  June,  1893. 


TBIBTTTB 

Tribute. 

Amount. 

T.              C.               Q.              LBS. 

£ 

«. 

d. 

Tin          i       :      6        :       3       :       23 

Price  £$2  per  ton 

Value  £70  is.  Sd. 

13/4 

46 

14 

5 

Keturning  charges 
Subsist  and  dressing 

£ 

8. 

d. 

10 

10 

3 
13 

6 
I 

Materials  and  drawing  . 

4 

4 

9 

Doctor,  club,  and  barber 

ii 

25 

12 

4 

Balance                                          £ 

21 

2 

i 

The  pay-ticket  shows  that  John  Jones  and  his  partners,  a 
gang  of  three  men,  raised  a  certain  quantity  of  crude  tin  ore 
(tinstuff)  which,  according  to  assays,  contained  i  ton  6  cwt. 
3  qrs.  23  Ibs.  of  clean  tin  ore  (black  tin).  The  value  of  this 
quantity,  at  £$2  per  ton,  is  £*]Q  is.  Sd.  The  pay -ticket  also 
states  that  the  tribute  was  13$.  ^d.  in  the  pound,  or,  in  other 
words,  two-thirds  of  the  value.  The  gross  total  credited  to 
the  gang  was  therefore  ^46  145.  $d.  Against  this  come  the 
returning  charges,  subsist,  dressing,  drawing,  and  sampling,  as 
follows  : — 

£    s.    d. 
Eeturning  charges  .         .         .  10    3     6 

Subsist  8  10    o 

Dressing 231 

Materials 2  10    8 

Drawing  and  sampling:    .         .         .         .         i   14     i 
Doctor,  55.,  Club,  4.9.  6d.,  Barber,  is.  6d.          on     o 

£25  12     4 

These  deductions  require  a  word  of  explanation.  The  return- 
ing charges  represent  the  cost  of  treating  the  "stuff "from  the 
time  it  goes  to  the  stamps  until  the  dressed  tin  .  ore  (black  tin) 


PKINCIPLES  OF  EMPLOYMENT. 


643 


is  fit  for  the  smelter.  The  amount  charged  varies  slightly  in 
different  mines.*  "  Subsist "  is  another  name  for  an  advance,  or 
money  paid  on  account,  during  the  running  of  the  contract,  which 
in  this  case  lasted  eight  weeks.  The  term  "  dressing"  as  used  in 
these  accounts  is  not  very  happily  chosen,  because  the  returning 
charges  represent  all  the  cost  of  stamping  and  washing.  The 
"  dressing  "  referred  to  in  the  pay-bill  is  the  preparation  of  the 
"tinstuff"  for  the  stamps  by  "ragging,"  "spalling,"  &c.  The 
charge  varies  from  4^.  to  6d.  per  ton,  according  to  the  hardness 
of  the  veinstuff.  In  this  case  the  books  of  the  company  showed 
that  96  tons  6  cwt.  i  qr.  of  tinstuff  had  been  dressed.  The 
"  materials"  included  candles,  powder,  fuse,  dynamite,  pick  hilts, 
detonators,  a  shovel,  clay  for  the  candles,  and  the  smith's  cost 
for  sharpening  drills  and  picks. 

"  Drawing "  is  the  Cornish  term  for  winding,  and  is  charged 
at  the  rate  of  $d.  per  ton.  The  "sampling"  refers  to  the  assays  of 
the  tin  ore  made  upon  the  vanning  shovel  by  the  mine  agent ; 
they  are  charged  at  the  rate  of  is.  each,  and  it  is  upon  the 
results  of  these  assays  that  the  mine-owner  ascertained  that  the 
96  tons  6  cwt.  i  qr.  of  "  tinstuff"  contained  i  ton  6  cwt.  3  qr.  23  Ib. 
of  "  black  tin."  One  of  the  three  men  being  a  bachelor,  paid  only 
6d.  per  month  for  the  doctor,  instead  of  the  usual  is.  of  the 
married  man,  whose  wife  and  family  are  likewise  entitled  to 
receive  medical  attendance. 

In  former  days  the  "  tribute,"  or  proportion  of  the  value  re- 
tained by  the  workmen,  was  publicly  fixed  by  Dutch  auction  on 
the  "setting"  day.  The  miners  assembled  outside  the  mine 
office  (counting-house),  and  the  manager,  after  reading  out  the 
nature  of  the  "  pitch,"  or  working  place,  asked  for  bids ;  the 
lowest  bidder  received  the  contract.  If  a  certain  place  seemed 
likely  to  be  profitable,  there  was  frequently  much  competition 
among  the  men  in  order  to  get  the  "  pitch."  Nowadays  the 
agreements  are  often  made  privately.  It  is  evident  that  the 
richer  the  lode,  the  smaller  will  be  the  proportion  of  the  value 
necessary  for  giving  the  men  a  fair  return  for  their  labour ;  in 
other  words,  the  tribute  will  decrease  as  the  lode  improves. 

This  system  of  working  has  many  advantages,  which  have 
rendered  it  popular  with  men  and  masters  in  Cornwall  and  else- 
where. The  man's  pay  does  not  depend  solely  upon  his  muscular 
exertion,  but  also  upon  his  judgment.  He  exercises  his  wits,  he 

*  Common  rates  are  : — 

«.  d. 

On  tinstuff  producing  i^  %  (or  less)  of  "  black  tin,"     2    o  per  ton. 

i4%  to  24%  3    o 

24%  »   3f%  3    6 

3i%   „   5    %  40 

5    %   „   6i%  50 

6i%  »    74%  7    o 

10    %  or  above  10    o 


644  OEE  AND  STONE-MINING. 

observes  the  nature  of  the  ground,  and  notices  what  conditions 
are  most  favourable  for  ore-bearing,  such  as  colour  and  texture 
of  the  surrounding  rock ;  what  signs  are  the  forerunners  of  richness 
or  poverty  of  the  lode,  such  as  intersections  with  "  droppers " 
or  "  feeders,"  joints  in  certain  directions,  "the  appearance  of  asso- 
ciated minerals.  Guided  by  slight  indications  of  this  kind,  which 
would  pass  unnoticed  by  the  inexperienced,  he  is  ready  to  back 
his  favourable  opinion  of  a  certain  working  place  (pitch)  by 
agreeing  to  work  it  at  a  price  (tribute),  which  would  seem  quite 
inadequate  if  one  judged  by  the  actual  ore  in  sight  at  the  time 
of  making  the  agreement.  If  he  is  correct  in  his  inference,  he 
may  make  a  large  sum  of  money,  and  receive,  for  instance,  one 
fourth  of  ^200,  instead  of  one-fourth  of  ^50,  which  seemed 
probable  from  the  original  appearance  of  the  ground. 

This  constant  study  of  the  geological  features  of  the  working- 
places  and  the  calculations  concerning  the  probable  expenditure 
for  explosives  and  other  materials,  educate  the  miner,  make  him 
brighter,  shrewder,  and  more  self-reliant,  and  so  raise  him 
mentally. 

The  advantages  of  this  training  are  also  felt  by  the  mining 
company;  they  have  in  the  mine  a  body  of  expert  detectives 
constantly  on  the  watch  for  clues  to  lead  them  to  hidden  ore- 
bodies  which  might  otherwise  go  undiscovered,  and  while  the 
tributer  is  at  work  in  any  given  "  pitch,"  the  mine-owner  feels 
little  fear  of  ore  being  thrown  away  in  the  rubbish,  or  of  "  waste  " 
being  unnecessarily  sent  to  the  surface.  As  the  interests  of  the 
employer  and  the  employed  are  in  these  respects  identical,  the 
former  knows  that  little  or  no  supervision  is  required  on 
his  part  to  prevent  loss  from  either  of  the  two  causes  just 
mentioned.  The  tributer  is  therefore  left  much  more  to  himself 
than  the  man  employed  upon  tutwork.  Lastly,  it  may  be 
pointed  out  that  so  long  as  the  profit  made  out  of  each  bargain 
is  sufficient  to  pay  its  proportion  of  the  general  expenses  of 
pumping,  ventilating,  and  management,  the  mining  company 
cannot  lose  by  employing  tributers.  It  is  not  to  be  wondered 
that  with  these  advantages  the  tribute  system  should  be  vaunted 
to  the  skies  by  many  mining  engineers. 

The  other  side  of  the  picture  must  not  be  forgotten.  In  the 
first  place,  the  system  is  apt  to  promote  duplicity  among  the  men. 
They  are  constantly  endeavouring  to  outwit  the  agent  by  fair 
means  or  foul,  and  will  candidly  confess  that  "  the  whole  art  of 
mining  is  fooling  the  captain."  The  latter  has  often  been  a 
tributer  himself,  and  is  fully  alive  to  all  the  tricks  which  the 
men  are  likely  to  practise  upon  him,  such  as  concealing  any 
indication  of  an  approaching  improvement,  in  order  to  get  better 
terms  at  the  next  "  setting."  This  is  not  all ;  it  may  happen  that 
two  "pitches"  not  very  far  from  one  another  are  being  worked 
at  very  different  tributes,  one  bargain  being  rich  and  the  other 


PRINCIPLES  OF  EMPLOYMENT.  645 

poor.  One  gang  may  be  getting  two-thirds  of  the  value  of  the 
ore  they  raise,  the  others  only  one-tenth ;  the  men  with  the  low 
tribute,  that  is  to  say,  the  men  in  whose  working  place  the  ore 
is  abundant,  are  often  ready  enough  for  a  consideration  to  part- 
with  some  of  their  stock  to  their  neighbours,  who  transfer  it 
secretly  to  the  "  pile  "  which  they  are  sending  up  to  the  surface, 
carrying  it  perhaps  from  one  working  place  to  the  other  in  an 
improvised  sack  made  out  of  a  pair  of  trousers.  The  result  is 
that  the  squad  with  the  high  tribute  are  paid  at  a  far  better  rate 
for  some  of  their  ore,  than  the  trouble  of  getting  it  warranted. 
When  the  rates  of  tribute  vary  between  narrow  limits  the  case  is 
different.  For  instance,  the  manager  of  a  zinc  mine  was  lately 
paying  405.  per  ton  for  blende  as  the  highest  tribute  and  305.  as 
the  lowest,  which,  with  the  ore  selling  at  ^5  per  ton,  corresponded 
to  8s.  and  6s.  in  the  pound  respectively ;  there  was  therefore  little 
or  no  temptation  to  transfer  ore  from  one  "  pitch  "  to  another, 
and  so  defraud  the  company. 

The  training  in  trickery  which  is  inherent  to  this  system  may 
have  its  effect  later  on,  when  the  tributer  is  promoted  to  a  higher 
position ;  from  having  been  taught  to  consider  that  cheating 
the  captain  is  perfectly  fair  and  legitimate,  he  may  be  ready  to 
conclude  that  "  the  whole  art  of  mining  is  fooling  the  public." 
And  blunting  of  the  moral  sense  of  the  men  is  an  undoubted 
•evil. 

Payment  by  tribute  involves  the  necessity  of  ascertaining  the 
value  of  each  gang's  raisings  separately.  In  the  case  of  tin  ore 
the  percentage  of  cassiterite  is  learnt  by  washing  a  sample  upon 
the  vanning  shovel,  and  from  the  result  of  this  assay  the  total 
amount  is  easily  reckoned ;  but  with  lead  and  zinc  each  parcel  is 
dressed  by  itself,  and  the  final  lots  of  clean  galena  or  clean  blende 
are  weighed  separately,  before  being  mixed  and  made  into  heaps 
for  sale  to  the  smelter.  This  multiplication  of  small  operations, 
cleanings-up,  and  weighings,  naturally  makes  the  cost  of  dressing 
higher  than  it  would  be  if  all  the  ore  were  treated  alike,  without 
regard  to  the  persons  who  had  raised  it. 

Another  objection  to  the  tribute  system  is  that  the  lessened 
amount  of  supervision  for  commercial  purposes  may  tend  to  a 
lessened  amount  of  supervision  for  purposes  of  security;  the 
working  place  is  not  visited  so  often  by  the  agent,  and  he  has  fewer 
opportunities  of  pointing  out  to  the  men  possible  dangers  from 
want  of  timbering  or  other  sources.  The  men  sometimes  court  this 
lack  of  supervision  by  making  access  to  their  "  pitch  "  difficult,  or, 
at  all  events,  troublesome.  Lastly,  there  is  an  element  of  gambling 
involved  in  the  tribute  system,  which  it  is  scarcely  advisable  to 
cultivate.  The  tributer  is  a  speculator,  who  hopes  by  a  lucky  hit, 
as  comrades  have  done  before,  to  make  a  lot  of  money  in  a 
short  time.  Where  one  succeeds  in  so  doing,  how  many  fail  ? 
According  to  the  report  of  Lord  Kinnaird's  Commission  in 


646  ORE  AND  STONE-MINING. 

1864,*  the  tutworker  at  that  time  was  better  housed  than  the- 
tributer  ;  the  moral  of  this  is  that,  on  the  whole,  it  is  better  for 
the  working  miner  to  be  in  receipt  of  fairly  constant  regular 
wages  than  to  trust  to  the  chance  of  occasional  runs  of  luck. 

The  advantages  accruing  to  a  mine  from  the  tribute  system  are 
far  less  marked  when  there  is  a  lode  of  pretty  even  character,  than 
when  the  deposit  is  fitful  and  uncertain  in  its  nature.  This 
explains,  to  some  extent,  why  the  tribute  system  occupies  a  less 
important  place  in  Cornwall  now  than  it  did  in  the  first  half  of 
this  century.  Cornish  mines  at  the  present  day  are  mainly 
dependent  upon  tin  lodes,  in  which  the  cassiterite  is  finely  dis- 
seminated through  a  hard  close-grained  rock.  The  consequence 
is  that  it  is  impossible  to  do  much  picking  underground,  or  indeed 
at  the  surface  ;  the  whole  of  the  stuff  raised  from  the  stopes  has 
to  be  sent  to  the  stamps.  For  deposits  of  this  kind  it  is  more 
advantageous  to  employ  the  tutworker,  who  excavates  the  ground 
at  so  much  per  fathom,  than  the  tributer.  Fifty  years  ago  things 
were  different ;  copper  was  then  the  mainstay  of  Cornwall,  and 
the  chief  ore  was  chalcopyrite.  While  cassiterite  is  a  mineral 
well  adapted  for  dressing  by  water,  chalcopyrite  is  not ;  it  crumbles 
to  dust  very  easily,  and  the  fine  particles  are  liable  to  be  washed 
away  with  the  refuse.  A  large  amount  of  hand-picking  was 
required,  in  order  to  save  as  much  of  the  ore  as  possible  from 
treatment  in  water.  The  care  of  the  tributer  in  the  stopes  of 
copper  mines  was  a  matter  of  vital  importance  in  the  old  days, 
and  his  services  were  really  valuable. 

Where  an  old  mine  is  re-worked  after  a  period  of  abandonment, 
the  tribute  system  often  does  good  service,  especially  if  the  object 
is  to  recover  some  mineral  considered  worthless  in  former  times, 
or  when  branches  of  ore  exist  in  the  sides,  after  the  main  part  of 
the  vein  has  been  removed. 

In  a  like  manner  it  proved  a  valuable  remedy  f  in  the  Eureka 
district  for  evils  which  had  resulted  from  the  plan  of  working 
the  ore  by  day  labourers.  The  ore  occurs  in  bodies  of  irregular 
shape  and  size ;  men  working  by  the  day  had  not  been  careful  to 
get  out  as  much  ore  as  they  might  have  done,  and  others  were 
induced  by  the  tribute  system  to  extract  the  portions  remaining 
behind,  which  would  otherwise  have  been  lost  altogether.  Besides 
which  it  was  known  that  small  ore-bodies  had  been  passed  over  as 
too  poor  or  too  insignificant  to  be  worth  removing  in  the  ordinary 
way,  but  which  were  quite  good  enough  to  afford  a  scope  for  the 
talents  of  a  man  who  had  a  direct  interest  in  the  ore  he  got  out. 
In  1881  the  men  received  $2-50  for  all  ore  assaying 


*  Report  of  the  Commissioners  appointed  to  Inquire  into  the  Condition  of 
all  Mines  in  Great  Britain  to  which  the  Provisions  of  the  Act  23  &  24  Viet, 
c.  151  do  not  apply. 

t  Curtis,  "  The  Silver-lead  Deposits  of  Eureka,  Nevada,"  Hon.  U.S.  Geol. 
Purvey,  vol.  vii.,  Washington,  1884,  p.  151. 


PRINCIPLES  OF  EMPLOYMENT.  647 

per  ton,  and  50  per  cent,  of  all  that  it  assayed  above  $30.  Thus 
an  ore  worth  $65  per  ton  brought  to  the  tributer  $2*50  + 
$17*50,  or  $20.  In  cases  of  this  kind  the  services  of  the 
tributer  are  often  requisitioned  with  good  results  to  the  mine ; 
that  is  to  say,  when  the  greater  part  of  the  ore  has  been  extracted 
by  some  other  method  of  payment,  and  when  more  judgment  and 
care  are  required  to  ferret  out  and  take  away  partly  hidden 
treasures  distributed  here  and  there  in  the  workings. 

Under  the  old  Cornish  system  of  tribute,  the  partners  are  all 
working  men,  who  are  all  employed  in  the  particular  "  pitch  " 
assigned  to  them  ;  but  in  Colorado  one  meets  with  a  modification 
of  the  method,  in  which  the  actual  miner  avails  himself  of  outside 
aid,  and  may  or  may  not  employ  labourers  who  have  no  interest 
in  the  adventure.  A  party  of  miners  who  have  confidence  in  the 
future  resources  of  some  part  of  a  mine,  take  it  upon  lease  and 
obtain  the  assistance  of  shopkeepers  or  others  in  the  neighbour- 
hood, in  order  to  buy  tools,  explosives,  and  materials,  and  to 
have  means  of  living  during  the  unproductive  stage  of  the  under- 
taking. If  the  hopes  of  the  miners  are  realised,  the  sleeping 
partners  receive  a  share  of  the  profits ;  if  the  speculation  turns 
out  badly,  the  miners  have  had  a  bare  subsistence,  and  the 
petty  capitalists  lose  their  money.  This  system  has  the  advantage 
that  it  enables  a  certain  amount  of  dead  work  to  be  combined 
with  the  extraction  of  ore.  Under  the  Cornish  system  working 
men  will  not  drive  levels  and  sink  shafts  in  unproductive  ground ; 
because,  however  high  the  tribute  may  be,  they  receive  nothing  so 
long  as  they  raise  no  ore,  and  they  cannot  afford,  on  their  own 
resources,  to  spend  weeks  and  months  in  making  the  preliminary 
openings,  which  may  be  required  before  some  given  block  of 
ground  is  made  ready  to  yield  up  its  supposed  riches.  A 
little  outside  capital  tides  the  workers  over  their  difficulty,  and 
gives  them  a  chance  of  making  money  by  the  exercise  of  their 
brains  as  well  as  by  the  expenditure  of  their  muscular  strength. 
The  question  will  be  asked  :  How  does  the  small  capitalist  guard 
himself  against  the  risk  of  having  to  provide  for  the  living  of 
some  lazy  miners,  who,  hidden  below  ground,  are  merely  making 
a  pretence  of  working  ?  In  the  first  place,  he  may  take  a  pre- 
caution, often  omitted  by  the  large  capitalist,  of  associating 
himself  only  with  men  whom  he  knows  and  can  trust,  and 
secondly,  as  he  is  frequently  a  bit  of  a  miner  himself,  he  visits 
the  mine  from  time  to  time,  and  watches  the  progress  of  the 
work. 

The  mine-owner  favours  this  system,  and  even  becomes  a 
partner  himself,  because  he  gets  some  of  his  dead  work  done 
without  any  risk  to  his  pocket.  In  the  case  of  mines  drained  by 
adit-levels  and  swept  through  by  natural  draughts,  as  is  commonly 
the  case  in  Colorado,  the  mine-owner  is  put  to  no  cost  whatever 
for  pumping  or  ventilation,  and  therefore  he  loses  no  money  even  if 


ORE  AND  STONE-MINING. 


the  "  lease  "  turns  out  a  failure,  whereas  he  is  bound  to  be  a 
gainer  if  any  ore  is  met  with. 

The   following   are   two   actual   examples   which    explain   the 
system  very  clearly  : — 


COLOEADO  LEASE. 

Profitable  Lease  to  both  Company  and  Lessee.     Company  or  Owner 
having  ^  interest)  and  Lessee  ^  interest. 

LEASE  ACCOUNT. 

Dr.  Or. 

$  c.  $     c. 

Nov.  30.  To  Lessee's  wages        .         .        .    '.   „  72.00 

,,  Other  wages    .         .         .        .        .  407.00 

„  Supplies,  powder,  &c.       .        .-      .  19.25 

,,  151  ore  sacks  .         .         .         .         -,  30.20 

„  Hoisting,  training,  &c.     .         .         .  99-55 

„  Blacksmithing         .         .         .         .  12.40 

,,  Hauling  ore  to  mill          .         ,         ,  26,70 

By  Proceeds  of  ore                .        *  .      .     .  2238.95 

To  Koyalty  .         .         .         ...         .  1119.40 

Dec.  30.    ,,  Lessee's  wages         .        ..''      .        .  78.00 

Other  wages   .               „  \         .         ,  573. 10 

Powder,  fuse,  &c.     .         ,         .         .  27.05 

100  ore  sacks  .         .         .         .         .  20.00 

Hoisting,  training,  &c.     .         ,     <.  ..  131.45 

Blacksmithing         .         .         .         ,  17.25 

Hauling  ore  to  mill          .         .         .  36.00 

By  Proceeds  of  ores     ....  3471-75 

To  Koyalty 1735.85 

4405-20  5710.70 

Net  profit  on  lease        ....       1305.50 

$5710.70          $5710.70 

Lessee  received : 

Wages  for  his  labour        .        .         .         .         150.00 
£  of  profits        .        .         .         .        '.         .         326.40 

476.40 
Company  or  owner  received : 

Royalty 2855.25 

|  of  profits 979. 10 

3834.35 
Cost  of  work  exclusive  of  lessee's  labour        .  1399-95 

Total        .         .  $57io.7o 


PRINCIPLES  OF  EMPLOYMENT. 


649 


COLORADO  LEASE. 

Unprofitable  Lease  to  Lessee.     Owner  \  Interest^  and  Lessee 
Interest. 


LEASE   ACCOUNT. 


Sept.  30.  To  Lessee's  wages 
Other  wages  , 
Powder,  fuse,  &c.    . 
Hoisting  and  training 
Hauling  ore  to  mill 
By  Proceeds  of  ore 
To  Royalty  . 

Oct.  31.     ,    Lessee's  wages 
Other  wages  . 
Powder,  fuse,  &c.    . 
Hoisting  and  training 
Hauling  ore  to  mill 
loo  ore  sacks  . 
By  Proceeds  of  ore 
To  Royalty  . 

Nov.  30.    „   Lessee's  wages    -    . 
,,   Other  wages  .        , 
,,   Powder,  fuse,  &c.    . 
„   Hoisting  and  training 
,,   Hauling  ore  to  mill 
By  Proceeds  of  ore 
To  Royalty   . 


Loss  on  lease 


Thus  the  lessee  received  : 

His  wages  for  working  amounting  to 
Less  half  loss  on  lease 

Leaving  him  for  his  work 

The  Company  received : 

Koyalty  amounting  to       .         .     '  . 
Less  half  loss  on  lease 

Net  profit  by  the  Company 


Dr. 

$    c. 

117.00 

442.30 

50-30 

07.85 

26.95 

660.80 
117.00 
483.90 

25.15 
66.95 
16.65 
17-35 


3846.60 


Cr. 
$    c. 


1321.60 


1070.20 


1322.60 


3714.40 
132.20 

3846.60 


356.20 
66.10 

290.10 


1857.20 
66..IO 

$1791.10 


The  men  who  are  excavating  slate  rock  (rock-men),  and 
those  who  are  subdividing  it  into  merchantable  slates  (quarry- 
men) ,  in  the  Festiniog  district,  are  paid  by  a  method  which 
in  principle  resembles  the  tribute  system.  The  earnings  of 
the  men  depend  upon  the  value  of  the  stock  of  merchantable 
slate  which  they  obtain  from  their  working  place  or  "  bargain." 
At  the  end  of  the  month  the  stock  of  each  partnership  is  counted, 


650  ORE  AND  STONE-MINING. 

and  the  men  are  credited  with  the  value  of  their  make  according 
to  a  fixed  tariff.  Thus,  for  instance,  we  may  suppose  that  the 
men  had  made  fourteen  hundred  slates  of  the  size  24"  x  14",  at 
27$.  6d.  per  thousand  ;  for  this  their  account  would  be  credited 
with  £i  1 8s.  6d.,  and  so  on  with  each  size.  On  looking  down 
an  account,  it  will  often  be  found  that  the  men  have  made  "  best  " 
slates  of  twenty  different  merchantable  sizes,  to  say  nothing  of 
several  kinds  of  "  seconds."  The  total  of  these  various  items  is  a 
first  basis  of  the  amount  due  to  the  partnership  ;  but  as  the 
"  rock  "  varies  in  quality  in  the  different  working  places,  owing  to 
the  presence  or  absence  of  joints,  the  interference  of  quartz  veins, 
or  alterations  of  texture,  the  result  of  a  given  amount  of 
labour  must  necessarily  vary  also.  In  good  rock  the  men  will 
make  a  large  quantity  of  "  best  "  slates  of  large  sizes ;  elsewhere, 
though  working  equally  hard  and  excavating  quite  as  many  cubic 
feet,  they  will  be  able  to  make  only  slates  of  small  sizes,  or 
"  seconds  "  in  the  place  of  "  bests."  The  companies  find  the 
simplest  method  of  adjusting  these  differences  is  to  pay  a  premium 
or  allowance,  varying  with  the  quality  of  the  rock  in  each 
"  bargain,"  and  determined  at  the  "  letting,"  i.e.,  at  the  time  of 
making  the  contract.  A  "  bargain  "  may  be  let  for  a  month  or  for 
several  months.  The  premium  is  called  "  poundage." 
Thus  to  take  an  actual  case  : 

£     s.    d. 

Value  of  the  slate  produced,  at  tariff  prices     .        .         16     19     i 
Poundage  io«.  .......          896 


Total    .        .     £25      8     7 

The  "  poundage  "  of  105.  means  a  premium  of  IDS.  in  the  pound ; 
for  every  pound's  worth  of  slate  at  tariff  prices,  the  workmen 
receive  an  additional  half-sovereign;  in  other  words,  the  value 
of  the  total  make  is  reckoned  at  50  per  cent,  more  than  the 
tariff"  prices.  If  the  bargain  is  a  good  one,  the  poundage  will  be 
low ;  if  the  rock  deteriorates  in  quality,  the  poundage  will  have 
to  be  raised  at  the  next  letting. 

Another  example  will  make  this  plainer : 

£     s.    d. 

Value  of  the  slates  produced,  at  tariff  prices  .         .          9     19     i 
Poundage  325.  6d.      .......         16       3     6 

Total    .         .      £26      2    7 

These  two  amounts,  ,£25  85.  yd.  and  £26  28.  yd.,  are  the 
gross  earnings,  in  each  case,  of  four  men  for  a  month,  and  are 
subject  to  deductions  for  materials  supplied. 

In  the  former  case  the  deductions  were  :  explosives,  6s.  6d., 
fuse,  is.,  candles,  45.,  smith,  55.  ii<#.,  or  175.  $d.  in  all,  leaving  a 
balance  of  £24  us.  2d.  which  was  handed  to  the  men.  In  this 


PRINCIPLES  OF  EMPLOYMENT. 


651 


bargain  there  were  three  partners,  who  employed  a  labourer,  and 
worked  twenty-four  days.  The  company  leaves  the  division  of 
the  money  to  the  men  themselves,  but  keeps  an  account  so  as  to 
know  precisely  what  the  earnings  are.  The  recognised  wages 
of  a  labourer  at  Festiniog  were  45.  2d.  a  day,  so  the  labourer  was 
paid  ^"5,  i.e.,  twenty-four  times  45.  2d.  There  remained,  there- 
fore, a  net  balance  of  ;£i9  us.  2d.  to  be  divided  among  three 
men.  According  to  the  time-book,  these  men  worked  70 J  days 
between  them,  and  therefore  their  average  wages  were  55.  6d. 
per  man  per  day. 

In  the  other  case  the  account  stood  thus  : 


£ 

«. 

d. 

Gross  earnings 

• 

- 

26 

2 

7 

DEDUCTIONS. 

£ 

s. 

d. 

Powder 

14 

IO 

Blasting  gelatine 

6 

6 

Detonators    . 

i 

6 

Fuse      . 

2 

o 

Candles 

4 

4 

Smith    .         . 

4 

6 

i 

13 

8 

Net  balance 

.     .  . 

£ 

24 

8 

ii 

Here  there  were  four  partners  and  no  labourer;  they  made 
94  days  between  them,  or  at  the  rate  of  55.  2d.  per  man  per 
day.  In  spite,  therefore,  of  the  very  great  difference  in  the  rock, 
the  poundage  was  so  fixed  beforehand  as  to  enable  each  set  of 
men  to  earn  very  nearly  the  same  wage  per  day. 

At  Festiniog  the  partnership  commonly  consists  of  four  per- 
sons :  two  working  below  ground,  and  engaged  in  getting  the  slate- 
rock,  and  two  working  above  ground  in  the  mills,  engaged  in 
making  the  blocks  into  merchantable  slates.  The  reason  for  this 
arrangement  is  the  fact  that  the  yield  of  slate  from  any  given 
block  depends  very  largely  on  the  skill  of  the  dressers,  and  if  the 
splitting  and  making  of  the  slates  were  confided  to  men  paid  by 
the  day,  these  would  have  no  interest  in  doing  their  best  with 
the  material  delivered  to  them.  Now  the  men  working  below 
ground  can  rely  upon  their  own  partners  to  work  up  the  blocks 
into  slates  with  the  least  possible  loss ;  the  case  is  a  totally 
different  one  from  dressing  a  metallic  ore.  Owing  to  the 
nature  of  the  substance  which  is  being  quarried,  the  payment  by 
a  varying  "  poundage  "  is  free  from  some  of  the  objections  which 


652  OHE  AND  STONE-MINING. 

are  inseparable  from  the  "  tribute  "  system  at  ore  mines.  At  the 
latter  the  change  in  the  value  of  a  lode  may  be  so  sudden,  that  a 
single  blast  will  convert  a  "  pitch  "  originally  "  set  "  at  a  tribute 
of  two-thirds,  into  one  which  could  be  worked  profitably  by  the 
men  at  one-twentieth.  If  such  a  change  takes  place  some  time 
before  the  end  of  the  contract,  the  men  raise  far  more  ore  than 
was  thought  possible  when  the  bargain  was  arranged,  and  make 
what  is  known  to  Cornishmen  as  a  "  start  "or  "  sturt,"  in  other 
words  "a  big  haul."  Cases  are  known  in  which  a  party  of 
tributers  have  earned  as  much  as  ^100  each  in  a  month,  instead 
of  the  expected  ^£4  or  ^£5.  The  possibility  of  such  good  fortune 
naturally  encourages  the  miner  to  take  the  risks  incident  to  work- 
ing upon  tribute,  and  at  the  same  time  prompts  him  to  deceive 
his  superiors  if  he  can.  With  slate,  the  "  rockman "  may  be 
favoured  by  unexpected  joints,  and  he  may  be  able  to  earn  twice 
as  much  as  was  expected  when  he  entered  into  his  contract,  but 
he  does  not  get  twenty  times  as  much,  nor  is  he  liable  to  find  his 
"  bargain"  so  suddenly  become  poor  or  absolutely  worthless  as 
may  happen  with  a  copper  lode  in  Cornwall.  There  are  also 
fewer  opportunities  of  hiding  coming  improvements  from  the  eyes 
of  the  agents.  The  result  is  that  there  are  fewer  attempts  at 
concealment,  and  consequently  there  is  less  chance  of  the  moral 
feeling  being  blunted  ;  sudden  great  variations  in  the  earnings  are 
rare,  and  the  solution  of  the  problem  of  payment  by  results  seems 
very  satisfactory. 

As  a  final  instance  of  the  payment  of  wages,  may  be  mentioned 
that  of  piecework  combined  with  premiums  for  good  conduct. 
This  system  was  introduced  at  the  large  stone  quarries  of 
Quenast  in  Belgium  *  in  order  to  make  the  men  stick  to  their 
work  during  the  regular  hours,  and  not  absent  themselves,  on  the 
pretext  that,  as  they  were  paid  by  results,  they  could  do  as  they 
pleased.  The  company  instituted  a  higher  rate  of  wages  and 
prices  applicable  only  to  men  who  did  not  leave  the  quarry 
during  working  hours  without  permission.  The  men  soon  dis- 
covered that  it  was  to  their  advantage  to  get  the  higher  tariff, 
the  public-houses  were  less  frequented,  the  average  earnings 
increased,  and  the  company  had  more  work  done. 

*  "  Continental  Notes,"  reporting  communication  by  Urban  to  Brussels 
Section  of  the  Liege  Engineers.  Coll.  Guard.,  vol.  Ixiii.  1892,  p.  844. 


CHAPTER  XV. 
LEGISLATION  AFFECTING  MINES  AND  QUAEEIES. 

Ownership — Taxation — Working  regulations  ;  Metalliferous  Mines  Regula- 
tions  Acts,  1872,  1875,  and  ^91  ;  Coal  Mines  Regulation  Act,  1887  ; 
Alkali  Acts — Boiler  Explosions  Acts — Brine  Pumping  (Compensation 
for  Subsidence)  Act — Elementary  Education  Acts — Employers' 
Liability  Act — Explosives  Act ;  Factory  and  Workshop  Acts — Quarry 
Fencing  Act — .Rivers  Pollution  Prevention  Act — Stannaries  Act,  1887 — 
Truck  Acts. 

THE  object  of  this  chapter  is  to  call  the  student's  attention  to  the 
principal  laws  affecting  the  working  of  mines  and  quarries  in  the 
British  Isles. 

The  subject  may  be  taken  under  the  following  heads  : 

1.  Ownership. 

2.  Taxation. 

3.  Working  regulations. 

4.  Sundry  special  statutes. 

i .  Ownership. — In  the  United  Kingdom  the  person  owning 
the  surface  is  primd  facie  entitled  to  all  the  minerals  under- 
neath, excepting  in  the  case  of  mines  of  gold  and  silver,  which 
belong  to  the  Crown.  The  Crown,  however,  does  not  claim  gold 
and  silver  extracted  from  the  ores  of  the  baser  metals.  Thus  we 
find  that  the  Crown  receives  a  royalty  for  the  gold  extracted 
from  auriferous  quartz  raised  upon  private  property  in  Wales, 
but  gets  nothing  whatever  for  the  silver  contained  in  argenti- 
ferous galena. 

The  ownership  of  the  minerals  can  be,  and  often  is,  severed 
from  that  of  the  surface,  the  latter  being  sold  whilst  the  mineral 
rights  are  reserved  by  the  original  owner.  Minerals  lying  under 
the  surface  between  high  and  low  water  mark  are  claimed  by  the 
lord  of  the  manor,  while  everything  under  the  sea  and  beyond  low 
water  mark  is  the  property  of  the  Crown. 

In  the  majority  of  cases  in  the  British  Isles,*  the  proprietor  of 
the  minerals  does  not  work  them  himself,  but  concedes  the  right 

*  Final  Report  of  the  Royal  Commission  appointed  to  Inquire  into  the 
subject  of  Mining  Royalties.  London,  1893.  This  Report  contains  much 
information  also  about  the  Mining  systems  of  the  Colonies  and  foreign 
countries. 


654  ORE  AND  STONE-MINING. 

to  another  person  in  return  for  an  annual  rent  and  a  royalty. 
Usually  a  certain  minimum  rent  is  fixed,  which  has  to  be  paid 
even  if  no  mineral  is  being  raised,  but  this  rent  merges  in  the 
royalties ;  that  is  to  say,  the  amount  paid  as  royalty  is  put  to  the 
credit  of  the  rent,  or,  if  sufficient,  covers  it  entirely. 
The  royalty  may  be  : 

(a)  A  fixed  sum  per  acre  worked. 
(&)  A  fixed  siim  per  ton  raised. 

(c)  A  fixed  proportion  of  the  value  of  the  mineral  raised. 

(d)  A  varying  proportion  of  the  value  of  the  mineral  sold,  regulated 

by  a  sliding  scale. 

The  first  principle  is  more  especially  adopted  in  the  case  of 
coal ;  on  the  other  hand,  a  fixed  rate  per  ton  is  common  in  the 
case  of  stratified  ironstone.  In  the  Cleveland  district,  the  royalty 
is  6d.  per  ton  on  an  average,  and  the  leases  extend  for  42 
years. 

Mineral  veins  are  generally  worked  upon  the  third  system ; 
royalties  vary  from  one-tenth  downwards,  though  this  amount  is 
quite  exceptional.  It  is  not  uncommon  for  the  lessee  to  pay  one- 
eighteenth  or  one-twenty-fourth  as  royalty,  and  if  a  mine  is 
struggling  against  low  prices  of  metal,  the  "lord"  is  often 
induced  to  abate  his  legal  claims  very  considerably,  or  even  to 
agree  to  forego  all  payments  until  trade  revives.  The  royalty  is 
calculated  upon  the  ore  made  ready  for  the  market.  Thus,  for 
instance,  in  one  of  the  reports  of  Dolcoath  mine  in  Cornwall  we 
read : 

By  tin  ore,  257  tons  igcwt.  I  qr.  ?lbs          .     ^19,596     13     6 
Deduct  G-.  L.  Basset,  Esq.,  dues  i-2oth.      .  979     16    8 

,£18,616     16-10 

Leases  in  Cornwall  are  usually  granted  for  21  years.  The 
lessor  stipulates  that  a  certain  number  of  men  shall  be  kept  con- 
stantly at  work.  Ground  for  tipping  rubbish  has  to  be  paid  for, 
and  sometimes  at  extravagant  rates.  When  a  lease  is  drawing  to 
a  close,  a  new  one  is  usually  granted  upon  terms  at  least  as 
favourable  as  those  of  the  old  ones;  but  cases  have  arisen  in 
which  the  "  lord  "  has  required  a  heavy  premium  before  he  would 
grant  a  new  lease. 

The  haematite  of  the  Carboniferous  Limestone  of  Cumberland 
and  North  Lancashire  is  usually  leased  upon  a  sliding  scale, 
which  increases  the  proportion  paid  as  royalty  when  the  price  of 
ore  goes  up.  Thus  if  iron  ore  is  selling  under  93.  per  ton  the 
lessor  receives  lod.  per  ton  as  royalty,  i.e.,  exactly  one-tenth  if 
the  price  is  8s.  4d.  Supposing  the  value  of  the  ore  to  rise  to  143. 
per  ton,  the  lessee  would  have  to  pay  2S.  or  one-seventh.  With 
intermediate  prices  the  fraction  might  be  one-eighth  or  one-ninth. 
The  leases  are  for  2 1  years. 


LEGISLATION  AFFECTING  MINES,  ETC.        655 

Many  centuries  ago  the  Crown  claimed  the  right  to  all 
minerals,  and,  in  order  to  promote  mining,  privileges  were 
granted  to  persons  who  would  endeavour  to  discover  and  work 
mines ;  from  these  privileges  and  from  old  usages  have  resulted 
special  mining  rights  peculiar  to  certain  districts.  Those  per- 
taining to  Derbyshire  have  now  been  definitely  fixed  by  two 
special  Acts  of  Parliament,  the  High  Peak  Mining  Customs  and 
Mineral  Courts  Act,  1851  (14  &  15  Viet.  c.  94)  and  the  Derby- 
shire Mining  Customs  and  Mineral  Courts  Act,  1852  (15  &  16 
Viet.  c.  43).  Again,  there  are  two  special  statutes  (i  &  2  Viet.  c. 
43  and  24  &  25  Viet.  c.  40)  which  regulate  the  opening  and 
working  of  mines  and  quarries  in  the  Forest  of  Dean,  where  the 
"  free  miners  "  have  certain  peculiar  rights. 

These  Acts  are  merely  of  local  importance,  but  they  are  of 
interest  as  preserving  old  customs. 

2.  Taxation. — Mining  companies  have  to  bear  their  share  of 
Imperial  taxes  and  local  rates.*     By  "  The  Rating  Act,  1874" 
(37  &  38  Viet.  c.  54)  tin,  lead,  and  copper  mines  are  assessed  on 
the  amount  of  dues  payable,  and  in  some  districts  a  large  pro- 
portion of  the  rates  may  be  paid  by  the  mines,  an  arrangement 
which  is  not  unfair,  if  they  are  the  cause  of  heavy  burdens  being 
thrown  upon  the  community. 

3.  Working  Regulations. — We  now  come  to  the  third  division 
of  this  chapter,  viz.,  the  statutory  regulations  which  are  in  force 
for  the  safe  working  of  mines. 

Special  legislation  for  promoting  the  safety  and  well-being  of 
the  miner  is  a  growth  of  the  last  half-century.  I  do  not  mean 
by  this  that  there  were  absolutely  no  regulations  in  days  gone  by  ; 
there  were  rules  which  had  grown  up  in  some  places,  from  customs 
and  privileges  so  carefully  preserved  that  they  had  become  laws, 
but  these  related  mainly  to  the  acquisition  and  preservation  of 
mining  property,  and  only  incidentally  to  the  prevention  of 
accidents. 

In  order  to  make  the  state  of  our  laws  clear,  and  especially  to 
those  who  may  be  accustomed  to  Continental  regulations,  it  is 
necessary  to  point  out  once  more  that  the  sources  from  which  we 
obtain  minerals  are  of  three  kinds  : 

a.  Open  works,  that  is  to  say  workings  open  to  the  sky. 

b.  Mines,  that  is  to  say  workings  carried  on  underground  by 
artificial  light. 

c.  Boreholes,   or    old    flooded    mines,   from   which    brine    is 
pumped. 

As  was  said  in  Chapter  I.,  it  is  the  nature  of  the  excavation 
and  not  the  nature  of  the  mineral,  which  settles,  in  this  country, 
whether  a  given  working  is  a  mine  or  not.  Consequently  it  must 

*  Coal,  Ironstone,  and  other  Mines  (Eating).  Parliamentary  Paper  No. 
405,  Session  1890.  Price  2\d. 


656  ORE  AND  STONE-MINING. 

be  understood  that  the  purely  mining  Acts  in  no  way  affect  open 
workings,  save  such  as  may  form  part  and  parcel  of  a  true  mine. 
The  actual  mining  statutes   now  in  force  are  as  follows,  in 
chronological  order : 

The  Metalliferous  Mines  Regulation  Act,  1872  (35  £36  Viet. 
c.  77). 

The  Metalliferous  Mines  Regulation  Act,  1875   (38  &  39  Yict. 

c.  39)- 

The  Slate  Mines  (Gunpowder  Act),  1882  (45  Viet.  c.  3). 

The  Coal  Mines  Regulation  Act,  1887  (50  &  51  Viet.  c.  58). 

The  Metalliferous  Mines  (Isle  of  Man)  Act,  1891  (54  &  55 
Viet.  c.  47). 

The  first  of  these  Acts  was  passed  after  the  report  of  the  Royal 
Commission  appointed  in  1860  to  inquire  into  the  condition  of  mines 
which  were  then  not  under  inspection,  and  it  was  made  to  embrace 
every  mine  to  which  the  sister  Act,  the  Coal  Mines  Act  of 
1872,  did  not  apply.  Therefore  every  mine  in  the  kingdom  is 
under  inspection  :  either  it  is  subject  to  the  provisions  of  the  Coal 
Mines  Act,  1887,  which  has  taken  the  place  of  the  1872  statute, 
or  it  is  under  the  Metalliferous  Act  of  1872.  The  former  Act 
applies  to  mines  of  coal,  stratified  ironstone,  shale,  and  fire-clay, 
and  therefore  the  latter  takes  cognizance  of  everything  else.  The 
titles  of  the  two  Acts  are  misleading.  Three  times  as  much  iron 
ore  is  obtained  from  mines  under  the  Coal  Act  as  from  mines 
under  the  Metalliferous  Act,  and  the  largest  mine  under  the 
latter  does  not  produce  metallic  ores.  Soon  after  the  passing  of 
the  Metalliferous  Act,  the  owners  of  an  underground  slate  quarry 
in  North  Wales  refused  to  have  their  workings  treated  as  mine?. 
They  asserted  with  some  plausibility  that  the  Statute  was  the 
"  Metalliferous  Mines  Act,"  and  that  their  workings  had  invariably 
been  known  as  "  quarries,"  and  never  as  "  mines."  The  matter 
had  to  be  brought  before  the  Court  of  Queen's  Bench,  and  there 
it  was  speedily  decided  that,  in  spite  of  popular  phraseology,  the 
Festiniog  underground  quarries  were  legally  "mines,"  and,  as 
such,  subject  to  inspection,  quite  as  much  as  the  Cornish  tin  mine, 
the  Cumberland  iron  mine,  or  the  Derbyshire  lead  mine. 

I  will  now  proceed  very  briefly  to  pass  in  review  the  most 
salient  points  of  these  two  Acts  of  Parliament,  beginning  with  the 
simpler,  and  incidentally  point  out  the  slight  modifications  intro- 
duced by  the  other  three  statutes  mentioned  in  my  list. 

The  Metalliferous  Act  is  divided  into  three  parts. 

Part  I.  deals  with  employment  of  women,  girls,  and  boys.  No 
females  can  work  below  ground,  nor  can  any  boy  under  1 2  years 
of  age.  Boys  under  16  cannot  be  employed  more  than  54  hours 
in  any  one  week,  or  more  than  10  hours  in  any  one  day. 

The  person  in  charge  of  machinery  for  raising  and  lowering 
men  must  be  a  male  of  at  least  18  years  of  age. 


LEGISLATION  AFFECTING  MINES,  ETC.         657 

Wages  must  not  be  paid  in  public-houses. 

An  Annual  Return  has  to  be  sent  every  year  to  the  Inspector 
of  Mines  of  the  district,  specifying  the  number  of  persons  em- 
ployed, and  the  output  of  mineral.  Under  the  1872  Act,  the 
mine-owner  was  not  obliged  to  furnish  this  return  for  any  given 
year  until  ist  August  following.  This  delay  in  the  despatch  of 
the  return  was  manifestly  absurd,  for  the  statistics  based  upon 
them  could  not  be  published  until  they  had  lost  much  of  their 
interest;  the  fault  in  the  1872  Act  was  corrected  by  the  short 
amending  Act  of  1875,  which  changed  the  date  from  the  ist 
August  to  the  ist  February  every  year. 

The  owner  *  or  agent  has  to  send  to  the  Inspector  of  Mines  of 
the  district  notice  of  every  fatal  accident,  of  every  accident  causing 
serious  personal  injury,  and  of  every  accident,  no  matter  how  trifling, 
causing  personal  injury  by  reason  of  any  explosion  of  gas,  powder, 
or  of  any  steam-boiler.  The  word  "  serious  "  gave  a  little  trouble 
at  first.  Some  agents  were  inclined  to  interpret  it  as  meaning 
"  likely  to  prove  fatal,"  and  did  not  report  broken  arms  and  legs, 
because  there  was  every  reason  to  suppose  that  the  man  would 
recover.  Nowadays,  when  the  period  of  disablement  is  likely  to 
exceed  a  week  or  ten  days,  the  accident  is  usually  notified. 

Notice  of  opening,  discontinuance,  recommencement  or  aban- 
donment, has  to  be  sent  within  two  months. 

The  section  which  follows  (sec.  13)  is  one  which  was  very  much 
wanted,  and  which  is  still  often  called  into  requisition.  It  is  the 
portion  of  the  Act  which  provides  for  the  secure  fencing  of  shafts 
and  side  entrances  of  mines  which  are  no  longer  at  work.  In 
working  mineral  veins,  the  "  old  men  "  sank  their  shafts  as  close 
to  one  another  as  they  still  do  in  mining  ozokerite  at  Boryslaw, 
and  the  surface  of  open  and  uninclosed  land  was  often  riddled 
with  holes  like  a  sieve.  If  the  tops  of  these  shafts  were  in  hard 
rock  or  were  lined  with  stone,  they  remained  open,  and  were  a 
source  of  danger  by  day  and  by  night,  for  many  were  close  to 
roads  or  foot-paths,  and,  when  partly  or  entirely  concealed  by 
brambles  or  bushes,  they  formed  veritable  man-traps.  In  other 
cases  the  timber  lining  at  the  top  had  decayed  and  the  ground 
had  run  in,  leaving  a  huge  yawning  crater,  10  or  20  yards  across, 
leading  to  a  pit  hundreds  of  feet  deep.  It  is  true  that  a  visible 
danger  of  this  kind  was  known  to  the  inhabitants  of  the  district 
and  could  be  avoided  by  daylight,  but  strangers  were  exposed 
to  a  considerable  amount  of  peril.  Five  and  twenty  years  ago  the 
state  of  some  of  the  open  commons  in  Cornwall  and  Flintshire  was 
simply  scandalous ;  and  even  now  there  are  often  good  grounds 
for  complaint  on  the  part  of  the  public,  as  fences  become  defective 
from  having  been  constructed  originally  in  too  flimsy  a  manner,  or 

*  The  word  "owner "has  a  special  interpretation  under  the  statute 
and  refers  to  the  lessee  or  company  working  the  mine,  and  not  to  the  pro- 
prietor of  the  soil  or  mineral  rights. 

2  T 


658  ORE  AND  STONE-MINING. 

from  the  mischievous  pranks  of  passers-by.  Occasionally,  too,  an  un- 
known shaft  comes  to  light  from  the  decay  of  the  platform  of 
planks  which  had  been  put  over  it  and  covered  with  earth  when 
the  mine  was  abandoned.  If  treated  in  this  way  the  top  soon 
becomes  grown  over  with  grass,  and  recollection  of  the  shaft 
gradually  fades  away.  These  timber  "  sollars,"  as  they  are  called, 
should  never  be  put  in  unless  there  is  also  a  secure  fence.  Many 
narrow  escapes  have  occurred  in  Cornwall  from  the  giving  way 
of  such  coverings,  where  the  presence  of  a  shaft  was  quite  un- 
suspected. 

Abandoned  mines  are  not  only  a  source  of  danger  to  the 
general  public  by  creating  pitfalls,  but  they  may  also  threaten 
the  workers  in  the  vicinity  by  holding  accumulations  of  water 
or  gas,  liable  to  be  tapped  unexpectedly  if  the  boundaries 
of  the  old  workings  are  not  known.  To  guard  against  such 
possibilities,  the  owner,  who  is  bound  to  keep  an  accurate  plan 
and  section  of  his  mine  during  the  progress  of  the  workings, 
is  further  obliged  to  deliver  up  a  copy  when  he  abandons  them  ; 
these  plans  are  filed  at  the  Home  Omce,  and  can  be  consulted  if 
necessity  arises.  They  serve  also  to  show  new-comers,  who  pro- 
pose to  reopen  an  old  mine,  what  work  has  been  done  by  their 
predecessors. 

The  next  section  of  the  Act  relates  to  the  Inspectors  of  Mines, 
who  are  appointed  by  the  Secretary  of  State  for  the  Home 
Department.  The  Inspector  may  not  practise  as  a  mining 
engineer,  manager,  agent  or  valuer  of  mines.  In  addition  to 
enforcing  the  provisions  of  the  Act,  the  Inspector  has  the  right  to 
complain  of  any  thing  or  practice  in  the  mine  which  is- 
dangerous,  or  defective,  or,  in  his  opinion,  threatens  or  tends  to 
the  bodily  injury  of  the  persons  employed.  In  order  to  prevent 
an  unreasonable  Inspector  from  pushing  matters  too  far,  the 
owner  and  agent  are  duly  safeguarded.  They  can  object  to  the 
Inspector's  notice  about  these  alleged  defects  and  have  the  matter 
referred  to  arbitration. 

Each  Inspector  has  to  make  an  Annual  Report,  which  is  laid 
before  Parliament  and  afterwards  published  as  a  Blue-book. 

This  is  a  convenient  place  for  explaining  that  the  United 
Kingdom  is  divided,  for  the  purposes  of  inspection,  into  thirteen 
districts,  each  under  a  Chief  Inspector,  who,  as  a  rule,  has  from 
one  to  three  assistants. 

The  following  separate  publications  are  issued  annually  by  the 
Home  Office : 

Report  by  each  Inspector  for  his  district. 
Statistical  Summaries  showing  the  number  of  persons  em- 
ployed, the  deaths  from  accidents,  and    the  quantity   of 
mineral  raised,  together  with  the   corresponding   figures 
for  previous  years. 
List  of  all  the  Mines  in  the  United  Kingdom. 


LEGISLATION  AFFECTING  MINES,  ETC.         659 

List  of  Record  Plans  deposited  at  the  Home  Office. 
Mineral  Statistics  of  the  United  Kingdom. 

The  last  section  of  Part  I.  of  the  Act  refers  to  the  duties  of 
the  coroner,  who  cannot  conclude  an  inquest  upon  the  body  of  a 
person  killed  by  a  mine  accident,  unless  due  notice  has  been  given 
to  the  Inspector  of  the  district.  As  a  rule  the  Inspector  attends 
the  inquest,  and  can  be  of  much  assistance  to  the  coroner  in 
eliciting  evidence,  for  he  will  have  seen  the  place  where  the 
accident  took  place,  and  will  know  whether  it  is  likely  that  it 
has  been  caused  by  pure  ill-luck  or  through  neglect  of  proper 
precautions. 

Part  II.  of  the  Act  contains  the  General  Rules,  and  sets  forth 
the  mode  of  establishing  Special  Rules. 

The  General  Rules  are  a  series  of  nineteen  regulations  which 
have  to  be  observed  in  every  mine. 

Ventilation. — Rule  i  relates  to  ventilation.  It  prescribes  that  an 
adequate  amount  of  ventilation  shall  be  constantly  produced,  so  that 
the  various  parts  of  the  mine  shall  be  in  a  fit  state  for  working 
and  passing  therein.  No  standard  of  ventilation  is  laid  down, 
nothing  is  said  about  the  number  of  cubic  feet  per  minute  that 
have  to  be  supplied,  nor  as  to  any  given  percentage  of  noxious 
gas  rendering  the  ventilation  "  inadequate." 

Explosives  and  blasting. — Rule  2  defines  how  explosives  are  to 
be  taken  into  the  mine,  and  lays  down  the  precautions  which 
have  to  be  observed  while  they  are  being  used.  Storage  under- 
ground is  forbidden ;  the  mine  should  have  a  proper  magazine 
above  ground,  from  which  explosives  should  be  dealt  out  daily  to 
the  miners  in  small  lots  as  required.  In  order  to  save  trouble  in 
keeping  the  account  of  the  small  daily  doles,  a  subsidiary  magazine 
is  sometimes  kept  up,  in  which  each  gang  of  men  has  a  locker.  A 
proper  attendant  then  serves  out  explosives  every  day  from  the 
lockers,  without  weighing  the  quantities. 

The  explosives  must  be  taken  into  the  mine  in  a  case  or 
canister  which  must  not  contain  more  than  four  pounds. 

Iron  and  steel  needles  or  prickers  are  prohibited,  but  the 
Secretary  of  State  has  power  to  exempt  mines  from  this 
restriction  if  he  thinks  fit.  Exemptions  of  this  kind  have  been 
granted  in  the  case  of  the  salt  mines  of  Cheshire.  Iron  and  steel 
tamping  bars  may  not  be  used  for  ramming  in  the  wadding  or 
the  first  part  of  the  tamping.  It  is  lastly  illegal  to  pick  out  or 
bore  out  the  tamping  of  a  charge  of  powder  which  has  missed 
fire. 

By  the  Slate  Mines  (Gunpowder)  Act,  1882,  the  Secretary  of 
State  has  power  to  relax  the  restrictions  concerning  explosives. 
This  Act  was  passed  for  the  convenience  of  workers  in  slate  mines, 
who  occasionally  have  to  fire  large  blasts  of  8,  10  or  12  pounds 
of  powder,  in  order  to  sever  a  large  block  of  slate  which  has  not 
been  completely  released  by  the  original  shot.  The  powder  is 


660  ORE  AND  STONE-MINING. 

sometimes  required  on  the  spur  of  the  moment,  as  water  might 
fill  up  the  crack  by  the  time  the  man  had  made  the  journey  to 
and  from  the  surface  for  a  supply.  Many  agents  of  slate  mines 
are  of  opinion  that  it  is  safer  to  carry  powder  into  the  mine  in 
the  25-pound  kegs  coming  direct  from  the  manufacturer  than  in 
the  ordinary  4-pound  canisters.  Where  exemptions  have  been 
granted  under  this  Act,  the  dangers  incident  to  storing  these 
kegs  of  powder  and  opening  them  by  candle-light  are  reduced  as 
far  as  possible  by  stringent  special  rules. 

Inclined  Planes  and  Horse  Roads. — Rules  3,  4,  and  5  relate  to 
signals  and  refuge  places  on  inclined  planes  or  horse  roads. 

Shafts. — In  Rules  6,  7,  and  8  are  very  important  regulations 
concerning  shafts.  The  sides  have  to  be  made  secure,  and  the  top 
of  the  shaft  and  all  entrances  to  it  have  to  be  fenced. 

Descent  and  Ascent. — The  next  seven  rules  relate  to  the  descent 
into  mines  and  ascent  therefrom,  whether  by  ladders  or  machinery. 

If  ladders  are  used,  the  ladderway  must  be  partitioned  off  from 
the  winding  compartment.  The  object  of  such  a  partition  is  not 
only  to  prevent  men  from  falling  into  the  winding  compartment, 
but  also  to  protect  them  from  stones,  which  might  drop  from 
the  bucket  or  skip  during  hoisting  operations.  Vertical  and 
overhanging  ladders  are  forbidden,  and  substantial  platforms 
are  required  at  intervals  not  exceeding  20  yards.  The  rule 
also  says  that  "  a  ladder  shall  be  inclined  at  the  most  convenient 
angle  which  the  space  in  which  the  ladder  is  fixed  admits." 
The  wording  is  unfortunate,  because  it  sometimes  fails  to  secure 
a  proper  inclination  for  ladders;  there  is  nothing  to  prevent 
a  person  from  sinking  too  small  a  shaft,  and  then  alleging 
want  of  space  as  an  excuse,  when  a  complaint  is  made  to  him 
about  the  great  steepness  of  his  ladders.  The  Belgian  law  is 
worded  better,  for  it  says  that  no  ladder  shall  be  inclined  at  an 
angle  of  less  than  10°  from  the  vertical. 

The  only  statutory  enactment  about  man-engines  is  that  they 
shall  be  partitioned  off  from  the  winding  compartment  of  the 
shaft. 

We  now  come  to  ascent  and  descent  by  winding  machinery. 
Guides  and  signalling  apparatus  are  required  as  soon  as  a  shaft 
exceeds  50  yards  in  depth,  and  a  cover  overhead  is  obligatory 
unless  an  exemption  has  been  granted  by  the  inspector.  A  single 
linked  chain  is  forbidden ;  the  winding  drum  must  be  provided 
with  flanges  to  prevent  the  rope  from  slipping  off;  there  must  be 
an  adequate  brake,  and  an  indicator  to  show  the  position  of  the 
load  in  the  shaft. 

Dressing-room. — It  was  quite  right  on  the  part  of  the  Legislature 
to  make  provision  by  Rule  16  for  a  changing  house,  or  "  dry," 
enabling  the  men  to  change  their  clothes  in  comfort,  and  have 
easy  means  of  drying  their  wet  underground  suits  ready  for  the 
next  day ;  but  the  wording  might  have  been  a  little  more  elastic. 


LEGISLATION  AFFECTING  MINES,  ETC.         661 

As  the  law  stands,  a  mine  need  not  have  a  "  dry  "  if  fewer  than 
thirteen  persons  are  employed  below  ground  ;  and  yet  one  meets 
with  wet  sinking  shafts  employing  only  ten  or  a  dozen  men, 
where  some  accommodation  is  desirable,  and  with  large  mines 
which  are  so  dry  that  a  changing  house,  as  generally  understood, 
is  superfluous. 

Fencing  Machinery. — Rule  17  prescribes  that  all  dangerous 
machinery  must  be  fenced. 

Steam  Boilers. — The  only  statutory  regulations  concerning 
steam  boilers  are  found  in  Rule  1 8,  which  says  that  every  such 
boiler  must  be  provided  with  three  fittings,  viz.,  a  steam  gauge, 
a  water  gauge,  and  a  safety  valve. 

Wilful  Damage. — The  last  Rule,  No.  19,  forbids  the  wilful 
damage  of,  or  removal  of  fences  or  appliances  provided  for  the 
safety  of  the  men. 

In  order  to  make  the  owner  and  agent  responsible  for  the 
proper  carrying  out  of  these  essential  regulations,  this  section  of 
the  Act  concludes  with  a  very  strict  clause.  As  a  rule,  in  this 
country,  a  man  is.  assumed  to  be  innocent  until  he  is  proved 
guilty.  In  mining,  it  is  different ;  if  a  contravention  of  the  Act 
by  any  person  whomsoever,  for  instance,  a  workman,  is  proved, 
the  owner  and  the  agent  are  each  made  guilty  of  an  offence  and 
are  liable  to  punishment,  unless  they  can  prove  that  they  had 
taken  all  reasonable  means  to  prevent  the  contravention  by 
publishing,  and  to  the  best  of  their  power,  enforcing  the  rules. 
The  Legislature  has  therefore  taken  strong  means  in  order  to 
render  the  miner's  calh'ng  safe.  On  the  other  hand,  the  owner 
and  agent  are  thoroughly  safeguarded  by  a  clause,  which  governs 
the  whole  of  the  section,  and  says  that  the  rules  are  to  be 
observed  "  so  far  as  may  be  reasonably  practicable." 

Special  Rules  may  be  regarded  as  by-laws  framed  to  suit 
the  conditions  of  any  particular  district  or  mineral  deposit; 
when  once  established  with  the  formalities  prescribed  by  law, 
they  have  all  the  power  of  the  statute  itself.  They  are  a  very 
useful  institution,  and  as  there  are  simple  means  of  modifying 
them,  changes  can  be  introduced  from  time  to  time,  without 
having  to  set  in  motion  the  ponderous  machinery  required  to 
alter  an  Act  of  Parliament.  At  mines  under  the  Metalliferous 
Act,  special  rules  are  not  compulsory  as  they  are  under  the  Coal 
Mines  Act ;  but  the  Secretary  of  State  can  propose  any  rules  he 
thinks  fit  to  the  owner  of  the  mine,  who  may  object  and  have  the 
matter  decided  by  arbitration. 

An  Abstract  of  the  Act,  and  a  copy  of  the  Special  Rules  (if  any) 
have  to  be  posted  up  in  a  conspicuous  place  at  the  mine,  where 
they  can  be  conveniently  read  by  the  workpeople.  The  name 
and  address  of  the  Inspector  of  the  district  have  to  be  appended, 
so  that  every  one  may  know  to  whom  to  apply  in  case  of  need. 

Part  III.  deals  with  penalties  for  offences  and  the  technicalities 


662  ORE  AND  STONE-MINING. 

relating  to  legal  proceedings.  The  penalties  to  which  a  person, 
is  liable  for  a  breach  of  the  Act  are  a  maximum  of  £20  if  he  is 
an  owner  or  agent,  and  a  maximum  of  £2  if  he  is  any  other 
person ;  the  fine  may  be  increased  by  £i  a  day  so  long  as  the 
offence  continues,  if  the  offender  has  received  notice  in  writing 
from  the  Inspector.  For  wilful  neglect,  endangering  life  and  limb, 
a  person  may  be  sentenced  to  imprisonment,  with  or  without 
hard  labour,  for  a  period  not  exceeding  three  months. 

The  owner  and  agent  cannot  be  prosecuted  except  by  an 
Inspector,  or  with  the  consent  in  writing  of  the  Secretary  of 
State.  The  workman  can  be  prosecuted  by  his  master ;  and 
proceedings  against  the  men  become  necessary  when  the  master 
finds  that  mere  words  fail  to  secure  strict  obedience  to  regula- 
tions, which  is  imperative  in  a  dangerous  occupation  like  mining. 

Strange  to  say,  the  clause  which  prevents  interested  magis- 
trates from  sitting  in  cases  under  the  Coal  Mines  Act,  is  omitted 
altogether  in  the  Metalliferous  Act. 

Where  a  penalty  amounts  to  or  exceeds  half  the  maximum,  the 
person  convicted  may  appeal  to  a  higher  court. 

The  last  Mining  Act,  that  of  1891.  was  passed  in  order  to 
correct  a  curious  omission  in  the  old  statute  of  1872,  which  failed 
to  define  the  Court  of  Summary  Jurisdiction  in  the  Isle  of  Man 
before  which  proceedings  could  be  taken. 

Having  thus  briefly  explained  the  statute  by  which  the  working 
of  many  ore  and  stone  mines  is  regulated,  we  must  now  pass  on 
to  the  Coal  Mines  Regulation  Act,  1887,  which  governs  mines  of 
stratified  ironstone,  shale  and  fireclay,  as  well  as  collieries.  Com- 
pared with  coal,  it  is  true  that  these  minerals  are  of  minor  import- 
ance; but  as  their  total  output  amounts  to  more  than  12,000,000 
tons  annually,  of  which  7,000,000  tons  are  ironstone,  it  is 
evident  that  even  the  ore  miner  should  be  acquainted  with  the 
requirements  of  this  statute. 

It  presents  many  points  of  resemblance  with  the  Metalliferous 
Mines  Regulation  Act,  but  it  is  far  more  elaborate  in  its  details ; 
to  save  repetition  it  will  be  best  to  dwell  more  especially  upon  the 
points  in  which  it  differs  from  the  Act  which  we  have  just  been 
discussing. 

In  Part  I.  the  principal  new  features  are  : 

Hours  of  Labour. — Regulation  of  the  hours  of  labour  of  boys 
and  females  employed  above  ground. 

Check  Weigher. — If  the  majority  of  the  men  wish  it,  they  may 
appoint  a  check  weigher  to  see  that  the  weighing  is  done  correctly, 
and  that  deductions  are  made  fairly. 

Prohibition  of  Single  Shafts. — The  object  is  to  provide  two 
means  of  egress  in  case  of  accident ;  certain  mines  may  be 
exempted  from  this  provision. 

Division  of  Mine  into  Parts. — Under  certain  circumstances 
each  part  must  be  treated  as  a  separate  mine. 


LEGISLATION  AFFECTING  MINES,  ETC.         663 

Certificated  Managers. — This  is  one  striking  difference  between 
the  Metalliferous  Act  and  the  Coal  Act.  Under  the  former  a  per- 
son without  any  pretensions  to  professional  qualifications  may  be 
placed  in  charge  of  a  mine ;  under  the  latter  every  mine  employ- 
ing more  than  thirty  persons  below  ground  must  have  a  certificated 
manager.  In  order  to  obtain  a  certificate  the  candidate  must 
have  had  practical  experience  in  a  mine  for  at  least  five  years,  and 
must  then  pass  an  examination.  For  the  purpose  of  granting 
certificates,  boards  for  examination  have  been  appointed  in  each 
of  the  twelve  districts  into  which  the  kingdom  is  divided  for  the 
purposes  of  the  Coal  Mines  Act.  Unfortunately  the  statute  makes 
no  provision  for  securing  uniformity  in  the  examinations.  Even 
the  limits  of  age  are  not  the  same ;  but,  nevertheless,  a  certifi- 
cate when  once  obtained,  is  good  for  any  part  of  the  kingdom. 

Returns. — The  Annual  Return  which  has  to  be  furnished  under 
the  Coal  Mines  Act  not  only  gives  the  output  of  the  mine  and 
the  number  of  persons  employed,  but  also  supplies  details  con- 
cerning the  mode  of  ventilation  ;  the  part  relating  to  the  quantity 
of  mineral  wrought  cannot  be  published,  save  by  consent  of  the 
person  making  it,  or  of  the  owner  of  the  mine.  This  restriction 
prevents  the  publication  of  such  details  as  appear  in  the  "  Mineral 
Statistics  "  in  the  case  of  mines  under  the  Metalliferous  Act. 

Inquests. — At  coroners'  inquests,  a  relative  of  the  person  killed, 
the  owner,  agent,  or  manager  of  the  mine  in  which  the  accident 
happened,  and  any  person  appointed  by  the  order  in  writing  of 
the  majority  of  the  workmen  employed  in  the  mine  may  attend 
-and  examine  witnesses.  No  such  power  is  conceded  under  the 
Metalliferous  Act. 

Part  II.,  as  in  the  other  Act,  contains  the  General  Rules,  and 
regulates  the  establishment  of  Special  Rules,  which  are  compul- 
sory instead  of  being  voluntary. 

The  General  Rules  are  38  in  number,  or  twice  as  numerous  as 
those  in  the  sister  Act.  They  may  be  passed  in  review  very  briefly 
.as  follows : 

Ventilation  (i,  2,  3). — Amount  of  ventilation  to  be  adequate; 
quantity  of  air  to  be  measured  monthly ;  special  airway  to  carry 
the  return  current  clear  of  the  ventilating  furnace ;  ventilating 
machines  to  be  placed  where  they  will  not  be  injured  by  explo- 
sions. 

Inspections  by  Officials  (4,  5). — The  working  place  has  to  be 
inspected  before  men  begin  their  work,  and  during  the  progress 
of  their  work.  Machinery  must  be  inspected  daily  and  shafts 
weekly. 

Fencing  (6). — Dangerous  places  must  be  fenced  off. 

Withdrawal  of  Men  (7). — Men  must  be  withdrawn  from 
dangerous  places. 

Safety-Lamps  (8,  9,  10,  n). — Use,  construction,  and  examina- 
tion of  safety-lamps.  Situation  of  lamp  stations. 


664  OEE  AND  STONE-MINING. 

Explosives  (12). — Prohibition  of  iron  and  steel  tools  for  charging 
holes,  and  special  precautions  for  blasting  in  mines  where  fire- 
damp has  been  noticed,  or  which  are  dry  and  dusty. 

Advance  Boreholes  (13). — These  are  made  compulsory  when 
approaching  water. 

Signalling  and  Man- Holes  for  Travelling  Roads  (14,  15,  16). — 
Very  like  the  rules  in  the  Metalliferous  Act. 

Dimensions  of  Travelling  Roads  (17). — Here  we  find  that  the 
comfort  of  animals  is  not  forgotten,  for  roads  must  be  big  enough 
to  allow  the  horses  or  ponies  to  pass  along  without  rubbing. 

Fencing  of  Shafts  (18,  19). — Very  like  the  rules  in  the  Metalli- 
ferous Act. 

Securing  of  Shafts  (20). — Identical  with  the  rule  in  the  Metalli- 
ferous Act. 

Securing  of  Travelling  Roads  (21). — This  very  useful  rule, 
though  contained  in  the  Coal  Mines  Act  of  1872,  was  not  incor- 
porated with  the  Metalliferous  Act. 

Timber  (22). — Props  have  to  be  provided  at  a  convenient  place 
in  the  mine. 

Descent  and  Ascent  (23  to  30). — In  addition  to  the  regulations 
found  in  the  Metalliferous  Act,  there  is  a  rule  preventing  a  speed 
of  more  than  three  miles  an  hour  after  the  cage  has  reached  a 
certain  point  in  the  shaft,  when  the  winding  apparatus  is  not  pro- 
vided with  some  automatic  contrivance  for  preventing  overwind- 
ing. Men  may  use  the  downcast  shaft  for  descent  and  ascent 
if  they  wish  to  do  so.  No  mention  is  made  of  ladders  or  man- 
engines,  which  are  not  in  use  at  mines  under  the  Coal  Mines  Act. 

Fencing  Machinery  (31). — Identical  with  the  Rule  in  the 
Metalliferous  Act. 

Fittings  for  Steam  Boilers  (32). — Very  like  the  Rule  "  in  the 
Metalliferous  Act. 

Barometer  and  Thermometer  (33). — These  have  to  be  placed  in 
a  conspicuous  position  at  the  mine. 

Ambulances  (34). — As  suffering  may  be  mitigated  or  life  saved 
by  having  proper  appliances  at  hand  for  relieving  and  moving 
injured  men,  the  statute  requires  that  stretchers,  splints,  and 
bandages  shall  be  kept  ready  for  immediate  use. 

Wilful  Damage  to  Fences,  or  Appliances  for  Safety  (35). — Very 
like  the  rule  in  the  Metalliferous  Act. 

Observance  of  Directions  (36). — Men  are  bound  to  obey  direc- 
tions with  respect  to  working,  given  with  a  view  to  comply  with 
the  Act  or  Special  Rules. 

Books  recording  Results  of  Inspections  (37). — These  have  to  be 
kept  at  the  office  of  the  mine. 

Periodical  Inspection  on  Behalf  of  Workmen  (38). — The  men 
may  appoint  two  practical  working  miners  to  inspect  the  mine,  at 
their  own  cost,  once  a  month.  The  result  of  the  inspection  has 
to  be  recorded  in  a  book,  and  if  the  report  states  the  existence  or 


LEGISLATION  AFFECTING  MINES,  ETC.         665 

apprehended  existence  of  any  danger,  the  inspector  has  to  be 
informed  of  it. 

Experienced  Workmen  (39). — Men  are  not  allowed  to  work  alone 
in  getting  coal  or  ironstone  at  the  face  of  the  workings  unless 
they  have  had  two  years'  experience  in  or  about  the  face  of  the 
workings  of  a  mine. 

Part  III.  relates  mainly  to  legal  proceedings,  and  the  only 
special  point  to  which  attention  need  be  called  is  the  section  which 
prohibits  persons  interested  in  mines,  or  their  near  relations,  from 
sitting  on  the  Bench  and  adjudicating  upon  breaches  of  the  Act. 

4.  Sundry  Special  Statutes. — It  might  be  thought  that 
statutes  framed  for  regulating  mines  would  contain  all  that  the 
law  requires  for  their  safe  and  proper  working ;  but  such  is  not 
the  case  in  this  country.  Miners  and  workers  of  open  pits  are 
often  affected  by  one  or  more  of  the  following  Acts  of  Parliament, 
which  are  arranged  in  alphabetical  order  : — 

Alkali,  &c.,  Works  Regulation  Acts,  1881  and  1892  (44  &  45 

Viet.  c.  37,  and  55  and  56  Viet.  c.  30). 
Boiler  Explosions  Acts,  1882  and  1890  (45  and  46  Viet.  c.  22, 

and  53  and  54  Viet.  c.  35). 
Brine  Pumping  (Compensation  for  Subsidence)  Act,  1891  (54 

and  55  Viet.  c.  40). 
Elementary  Education  Acts,   1870  to  1891   (33  and  34  Viet. 

c.  75  ;  38  and  39  Viet.  c.  79,  and  43  and  44  Viet.  c.  23 ; 

53  and  54  Viet.  c.  22 ;  54  and  55  Viet.  c.  56). 
Employers'  Liability  Act,  1880  (43  and  44  Viet.  c.  42). 
Explosives  Act,  1875  (38  Viet.  c.  17). 
Factory  and  Workshops  Acts,  1878  and  1891   (41  and  42  Viet. 

c.  1 6,  and  54  and  55  Viet.  c.  75). 
Quarry  Fencing  Act,  1887  (50  and  51  Viet.  c.  19). 
Rivers  Pollution  Prevention  Act,  1876  (39  and  40  Viet.  c.  75). 
Stannaries  Act,  1887  (50  and  51  Viet.  c.  43). 
Truck  Acts,  1831  and  1887  (i  and  2  William  IV.  c.  37,  and 

50  and  51  Viet.  c.  46). 

The  Alkali  Acts  were  passed  with  a  view  to  prevent  noxious 
and  offensive  gases  produced  in  manufacturing  processes  from 
being  discharged  into  the  atmosphere,  or  at  all  events  to  reduce 
their  escape  to  a  minimum.  These  Acts  apply  to  a  few  mineral 
workings — viz : 

(1)  Salt  works  in  which  brine  is  being  evaporated  for  the  manufac- 

ture of  salt. 

(2)  Cement  works  in  which  clays  are  made  into  cement. 

(3)  Tin  and  copper  mines  where  ores  containing  arsenic  are  being 

roasted. 

(4)  Collieries  where  tar  and  ammoniacal    liquor,  obtained  from  the 

waste  gases  of  coke  ovens,  are  being  treated  ;  the  former  is  dis- 
tilled for  the  production  of  paraffin  and  burning  oils,  the  latter 
is  made  into  sulphate  of  ammonia. 


666  ORE  AND  STONE-MINING. 

The  Acts  are  administered  by  Inspectors  under  the  Local 
Government  Board. 

The  Boiler  Explosions  Acts  compel  the  owner  of  a  mine  to  report 
to  the  Board  of  Trade  any  explosion  of  a  steam  boiler,  which  may 
happen  at  his  works  whether  above  or  below  ground.  The  Board 
of  Trade  officials  can  then  make  a  preliminary  investigation  into 
the  cause  of  the  explosion,  and  afterwards  hold  a  formal  inquiry 
if  they  think  fit.  The  Court  holding  this  formal  inquiry  is 
usually  composed  of  two  Commissioners  specially  appointed  by  the 
Board  of  Trade,  who  are  endowed  by  the  Acts  with  ample  power 
for  punishing  the  owners  and  agents  of  mines,  if  an  explosion  has 
in  any  way  been  caused  by  their  neglect.  The  Commissioners 
cannot  inflict  a  "  fine  "  in  a  criminal  sense,  such  as  is  imposed  by 
a  Court  of  Summary  Jurisdiction  at  proceedings  taken  under  the 
Mines  Regulation  Acts ;  but,  where  neglect  has  been  proved,  the 
responsible  persons  have  been  ordered  to  pay  as  much  as  ^100 
or  ;£i2o  to  the  solicitor  of  the  Board  of  Trade  "towards  the 
costs  and  expenses  of  the  investigation,"  which  practically  comes 
to  the  same  thing.  Under  the  Mines  Regulation  Acts  the  mine- 
owner  can  appeal  to  a  superior  court  and  have  the  matter  re-heard ; 
but  the  decision  of  the  Commissioners  under  the  Boiler  Explosions 
Act  is  final  and  not  subject  to  review. 

The  Brine  Pumping  Act  provides  compensation  for  owners  of 
property  who  suffer  through  the  subsidence  of  the  ground  caused 
by  the  pumping  of  brine.  The  working  of  the  Act  is  controlled 
by  the  Local  Government  Board. 

The  Elementary  Education  Acts  make  provision  for  the  educa- 
tion of  children :  they  prohibit  absolutely  the  employment  of 
children  below  the  age  of  10,  and  do  not  permit  the  employment 
of  children  below  the  age  of  13  unless  they  have  reached  the 
standard  of  education  fixed  by  the  by-laws  in  force  in  the 
district.  Children  between  13  and  14  are  allowed  to  work  if  they 
can  produce  a  certificate  of  proficiency  or  of  previous  due  attend  - 
ance  at  school.  After  they  have  attained  the  age  of  14,  they  are 
no  longer  "  children  "  within  the  meaning  of  the  Education  Acts. 

The  Employers'  Liability  Act  extends  and  regulates  the  liability 
of  employers  to  make  compensation  for  personal  injuries  suffered 
by  workmen  in  their  service.  Until  this  Act  was  passed  a  work- 
man could  not  claim  compensation  for  injuries  due  to  the  neglect 
of  a  fellow-servant.  The  statute  of  1880  has  broken  down  this 
doctrine  of  "  common  employment  "  to  a  certain  extent,  and  has 
made  the  master  liable  if  the  injury  was  caused  by  the  negligence 
of  a  foreman  or  person  entrusted  with  superintendence  ;  but  it 
•does  not  make  the  master  liable  for  the  negligence  of  all  the 
fellow-servants. 

The  Explosives  Act  regulates  the  manner  in  which  licences  for 
storing  explosives  are  obtained,  the  construction  and  maintenance 
of  the  magazines  at  mines,  the  subdivision  of  the  trade  packages, 


LEGISLATION  AFFECTING  MINES,  ETC.          667 

;and  the  delivery  to  the  men.  The  Act  is  enforced  by  Inspectors 
under  the  Home  Department,  and  also  by  the  Police  on  behalf 
of  the  Local  Authorities. 

The  two  Factory  and  Workshop  Acts,  which  are  enforced  by 
Inspectors  serving  under  the  Home  Department,  apply  to  certain 
quarries,  and  to  surface  works  at  mines  under  the  Metalliferous  Act, 
such  as  the  dressing  sheds.  They  contain  provisions  for  promoting 
the  health  and  safety  of  the  workpeople,  and  regulate  the  hours 
of  employment  of  women,  young  persons,  and  children.  It  is 
probable  that  all  quarries  will  eventually  be  placed  under  the 
•supervision  of  the  Inspectors  of  Mines. 

The  object  of  the  Quarry  Fencing  Act  is  evident  from  its  title, 
£,nd  it  is  the  business  of  the  Local  Authorities  to  see  it  enforced. 

By  section  5  of  the  Rivers  Pollution  Prevention  Act,  the  mine- 
owner  is  prohibited  from  discharging  into  streams  any  solid 
matter  in  such  quantity  as  to  prejudicially  interfere  with  its  flow, 
or  any  poisonous,  noxious  or  polluting  solid  or  liquid  matter, 
unless  he  proves  that  he  is  using  the  best  practicable  and  reason- 
ably available  •  means  to  render  such  matter  harmless.  The 
administration  of  this  law  rests  with  the  Sanitary  Authority  of 
the  district,  and  in  this,  as  in  other  matters,  the  work  of  the 
.Sanitary  Authorities  is  supervised  by  Inspectors  acting  under  the 
Local  Government  Board. 

The  large  amount  of  refuse  which  is  produced  in  extracting 
some  minerals  from  their  ores,  makes  the  task  of  getting  rid  of 
it,  without  polluting  the  rivers,  far  from  easy;  and  the  miner 
often  incurs  the  wrath  of  the  fisherman,  who  stirs  up  the 
Sanitary  Authorities  or  River  Conservancy  Boards  into  action. 
Coarse  waste,  such  as  comes  from  jigging  the  larger  sizes  of 
the  crushed  rock,  can  always  be  made  into  heaps  upon  the 
land ;  but  the  fine  slimes,  whether  coming  from  stamping  or 
other  dressing  processes,  are  carried  away  in  suspension,  and  turn 
a  bright  trout  stream  into  a  muddy  drain,  or  are  spread  over  the 
meadows  in  flood  time,  to  the  annoyance  of  the  farmer.  These 
evils  may  be  greatly  lessened  by  providing  large  pits  into  which 
the  water  from  the  mine  is  allowed  to  settle,  and  so  deposit  much 
of  the  solid  matter  which  it  contains  in  suspension.  Effective 
filtering  pools  have  been  made  in  Germany  from  the  coarse 
refuse  (skimpings)  from  the  jigs.  It  is  tipped  so  as  to  form 
high  banks  enclosing  a  rectangular  area,  into  which  the  muddy 
water  from  the  "  floors"  is  led,  and  allowed  to  form  a  large 
pool.  Some  of  the  solid  matter  settles  down  on  the  bed  of  the 
pool,  as  it  would  do  in  any  ordinary  pond,  and  the  rest  is  deposited 
in  the  bank  itself,  as  it  permeates  through  the  tortuous  passages 
left  between  the  little  fragments  of  stone.  In  time,  the  inner 
.sides  of  the  banks  become  somewhat  choked  with  slime  and  the 
percolation  no  longer  proceeds  so  rapidly;  this  state  of  things  is 
remedied  by  letting  out  the  water  during  a  holiday,  and  scraping 


668  ORE  AND  STONE-MINING. 

down  the  sides,  so  as  to  expose  a  fresh  unchoked  surface  to  the 
slimy  water.  Old  heaps  of  mine  refuse  can  be  utilised  in  a 
similar  manner ;  the  stream  of  dirty  water  led  into  the  top  will 
escape  fairly  clear  at  the  bottom.  As  soon  as  one  part  of  the 
heap  becomes  choked  with  slime,  the  out-fall  of  the  "  floors  "  must 
be  shifted  to  another  part  of  the  bank. 

The  Stannaries  Act,  1887,  was  passed  to  remedy  certain  evils  of 
which  miners  and  shareholders  complained  at  mines  in  Cornwall 
and  Devon.  The  Act  extends  only  to  metalliferous  mines  and  tin 
streaming  works — i.e.,  works  where  tin  ore  is  extracted  from  the 
dirty  water  flowing  away  from  mines,  within  the  Stannaries. 
The  miner  now  has  a  first  charge  upon  the  property  of  a  mining 
company,  and  is  less  likely  to  lose  his  earnings  when  a  mine  is 
stopped  for  want  of  funds,  than  he  was  some  years  ago.  Surface 
hands  have  to  be  paid  once  a  fortnight;  miners  employed  by 
contract  below  ground  are  entitled  to  claim  "  subsist "  once  a 
fortnight — that  is  to  say,  a  payment  on  account  equal  to  the  esti- 
mated amount  of  their  earnings.  Money  deducted  for  sick  and 
accident  funds  has  to  be  accounted  for,  and  a  copy  of  the  balance- 
sheet  must  be  posted  up  in  the  "  dry  "  or  changing  house.  The 
miners  have  the  power  to  appoint  a  check-weigher.  Meetings  of 
the  shareholders  of  every  "  cost  book  "  mine  must  be  held  at  least 
once  in  every  sixteen  weeks.  Tools  and  materials  supplied  to  the 
miners  have  to  be  charged  as  nearly  as  possible  at  the  market 
prices.  Other  regulations  relate  to  the  settlement  of  disputes,, 
mortgages,  relinquishment  of  shares,  and  registration  of  companies, 
A  copy  of  the  Act  has  to  be  kept  posted  up  in  the  smith's  shop 
and  in  the  changing  house  of  every  mine. 

The  object  of  the  Truck  Acts  is  to  prevent  the  mine  owner  from 
making  a  profit  out  of  the  tools  and  materials  which  he  supplies 
to  his  men ;  but  he  has  a  right  to  make  deductions  from  the  men's- 
wages  for  medicine,  medical  attendance,  materials  and  tools,  pro- 
vided that  they  agree  in  writing  to  this  system.  As  a  rule  the- 
men  would  sooner  obtain  the  necessaries  for  their  work  in  this 
way,  than  purchase  them  at  the  shops  in  the  district.  The 
Truck  Acts  have  to  be  enforced  at  mines  by  the  Inspectors 
under  the  Mining  Acts. 

From  the  foregoing  pages  it  is  very  evident  that  the  manager 
of  a  mine  in  this  country  may  have  to  make  himself  well  acquainted 
with  a  considerable  number  of  legal  enactments,  mostly  of  recent 
date,  if  he  desires,  as  he  should  do,  to  carry  on  his  work  in  strict 
accordance  with  the  law. 


669 


CHAPTER   XYI. 
CONDITION  OF  THE  MINER. 

Clothing  :  hat,   boots,    jacket — Housing :  barracks,    cottages,    changing 
houses — Education — Sickness — Thrifc — Recreation. 

IT  is  perfectly  impossible  to  do  justice  to  the  importance  of  this 
subject  in  the  few  pages  that  can  be  devoted  to  it  in  a  general 
text-book;  but  the  following  remarks  will  serve  to  call  the 
attention  of  the  student  to  matters  with  which  he  may  have  to 
deal  when  he  enters  into  the  active  duties  of  his  profession,  and 
becomes  either  an  employer  of  labour  himself,  or  the  agent  of  a 
mining  company. 

I  propose  to  treat  the  subject  under  the  following  heads : 


1.  Clothing. 

2.  Housing. 

3.  Education. 

4.  Sickness, 
Thrift. 
Recreation. 


I 


i.  CLOTHING. — At  the  surface  we  clothe  ourselves  in  order 
to  keep  our  bodies  warm,  and  to  protect  ourselves  from  the  sun 
and  rain ;  in  the  mine  the  conditions  are  totally  different,  and  the 
clothing  may  be  altered  accordingly.  On  the  whole  the  tem- 
perature is  more  uniform  than  it  is  above  ground ;  the  miner  in 
most  cases  finds  his  working-place  warmer  in  winter  and  cooler 
in  summer  than  it  would  be  if  he  were  working  in  the  fields  in 
the  neighbourhood.  It  is  the  exception  to  have  the  temperature 
below  32°  F.  in  mines  even  in  winter.  Occasionally  in  this 
country  a  freezing  wind  rushing  down  the  shaft  will  coat  the 
ladders  with  ice  and  make  climbing  unpleasant  and  risky,  and 
where  the  climate  is  cold  and  the  openings  to  the  surface  large, 
the  effects  of  frost  are  felt  far  deeper  than  they  are  here.  The 
sinkings  through  alluvial  deposits  in  Siberia  are  instances  of 
great  cold  in  mines;  and  even  where  the  operations  are  more 
truly  underground  the  temperature  is  sometimes  below  freezing 
point.  This  is  the  case  at  the  Algachi  silver  mine.* 

The  other  extreme  was  found  in  the  workings  on  the  Comstock 

*  Kennan,  "  In  East-Siberian  Silver  Mines,"  The  Century  Magazine, 
vol.  xxxviii.,  1889,  p.  803. 


670  ORE  AND  STONE-MINING. 

lode.*  In  the  year  1868,  when  a  depth  of  1000  to  1200  feet  had 
been  reached,  the  heat  in  some  drifts  was  becoming  unbearable. 
In  August  1868  at  a  depth  of  1 100  feet  in  the  Chollar-Potosi  Mine, 
the  temperature  was  100°  F.  (37*7  C.),and  in  the  lower  level  of  the 
Hale  and  Norcross  1 10°  F.  (43*3  C.)  In  June  1870  at  the  goo-foot 
level  of  the  Yellow  Jacket  Mine  the  temperature  was  97°F.  (36-1  C.) 
at  a  point  only  300  feet  from  the  shaft,  although  blowers  were  at 
work.  The  highest  temperatures  were  observed  when  long  levels 
were  driven  without  any  ventilating  shafts  or  winzes.  As  soon  as 
a  proper  air-current  was  established  the  temperature  usually  sank 
rapidly.  Thus  the  thermometer  stood  at  130°  to  140°  F.  (54  to 
60°  C.)  in  a  drift  at  the  i85o-foot  level  of  the  Bullion  Mine,  but 
when  connection  was  made  with  another  shaft  the  thermometer 
went  down  to  100°  F.  (37*7°  C.)  The  miners  working  in  the  hot 
levels  were  supplied  with  ice,  which  was  sent  down  by  the  ton. 
Their  average  daily  consumption  in  the  hottest  parts  of  the 
California  and  Consolidated  mines  during  the  summer  of  1878 
was  95  pounds  of  ice  per  man,  and  they  would  commonly  drink 
as  much  as  three  gallons  of  water  in  the  shift  of  eight  hours. 

It  was  not  only  the  air  of  the  mine  which  was  hot,  the  water 
was  even  hotter.  The  spring  in  the  Savage  mine  had  a  tempera- 
ture of  no  less  than  157°  F.  (69*4°  C.),  and  the  incline  was  filled 
with  scalding  vapour.  Up  to  the  end  of  1877  *ne  highest  recorded 
temperature  of  the  water  was  154°  F.  (67*7°  C.) ;  but  since  then  an 
increase  in  the  water  temperature  to  i7o°F.  (76*6°  C.)  has  been 
noted.  The  Comstock  mines  are  the  hottest  in  the  world. 

At  Dolcoath,t  the  largest  and  deepest  tin  mine  in  Cornwall,  the 
temperature  of  the  water  issuing  from  the  rock  in  the  lowest 
workings  is  nearly  100°  F.  (37'7°  C.)  and  that  of  the  air  96°  F. 
(35-5°  C.)  The  bottom  level  is  now  2424  feet  vertically  below  the 
surface. 

In  the  adjacent  Cook's  Kitchen  mine,  which  approaches  its 
neighbour  in  depth,  the  air  in  the  end  of  the  394-fathom  level,  at 
no  great  distance  from  a  winze,  will  raise  the  thermometer  to 
95°  F.  (35°  C.),  whilst  in  the  ends  of  the  420-fathom  level,  driven 
out  but  a  very  short  distance  from  the  bottom  of  the  shaft,  the 
temperature  of  the  air  is  100°  F.  (37*7°  C.)  and  that  of  the  water 
slightly  higher.  Some  workings  for  copper  at  St.  Day,  Cornwall, 
were  even  hotter,  but  the  mine  has  long  been  abandoned.  The 
submarine  mines  near  the  Land's  End  are  also  warm,  and  air- 
temperatures  above  90°  F.  (32°  C.)  are  often  recorded.  In  Corn- 
wall, as  in  Nevada,  the  hottest  places  are  "  ends  "  or  "  rises ''" 
before  they  are  "  holed  "  to  other  workings.  When  once  a  com- 
munication has  been  effected  and  a  through  draught  established, 
the  rock-faces  cool  down  quickly. 

*  Lord,  "  Comstock  Mining  and  Miners,"  Monographs  U.S.  Geol.  Survey,. 
Washington,  1883,  p.  391  et  seq. 

t  MS.  information  from  Mr.  W.  Thomas,  F.G.S.,  1893. 


CONDITION  OF  THE  MINER.  671 

With  the  temperatures  just  mentioned,  it  is  evident  that  the 
miner  requires  very  little  clothing,  but  even  when  the  air  is 
comfortably  cool,  he  often  strips  himself  to  the  waist,  in  order  to 
secure  that  freedom  of  limb  which  so  much  conduces  to  the 
efficiency  of  muscular  labour. 

In  some  cases,  such  as  in  the  salt  mines  of  this  country, 
the  working-places  are  very  comfortable ;  indeed  the  miner  is 
better  off  than  the  labourer  at  the  surface.  He  is  not  exposed  to 
the  burning  sun,  cutting  winds  or  torrents  of  rain ;  but  he  works 
in  a  cool  and  pleasant  atmosphere,  varying  little  in  temperature, 
and  he  has  not  to  assume  a  cramped  posture.  On  the  other  hand,  the 
miner's  working- pi  ace  may  be  moist  and  steaming,  or  hot,  dry  and 
dusty,  or  cold,  wet  and  draughty ;  and  on  reaching  the  surface  in 
a  cage,  he  may  have  to  face  an  icy  blast  after  leaving  a  tropical 
atmosphere  only  a  minute  or  two  before.  Where  circumstances 
are  so  unlike,  the  clothing  worn  in  the  mine  must  necessarily  vary, 
to  say  nothing  of  differences  in  attire  due  to  the  habits  of  the  people. 
The  South  African  native,  content  with  a  waist-cloth  above 
ground,  requires  nothing  more  when  he  descends  into  the  diamond 
mines,  whilst  the  white  man,  true  to  his  bringing  up,  needs,  or 
thinks  he  needs,  more  abundant  vestments. 

Hat. — Some  of  the  clothing  used  below  ground  has  to  serve  a 
different  purpose  to  that  required  of  it  at  the  surface.  One  object 
of  the  miner's  hat  is  to  preserve  his  head  from  blows,  as  he  walks 
along  low  and  rugged  tunnels,  and  from  falls  of  stones  while  work- 
ing in  shafts.  The  Cornishman  wears  a  hat  made  of  felt  and 
rosin,  shaped  like  an  ordinary  "  pot  hat "  of  everyday  life.  It  is 
cheap  and  durable,  and  affords  admirable  protection  against  hard 
raps  ;  but  it  is  not  ventilated,  and  it  is  heavy,  weighing  about  one 
pound,  or  four  times  as  much  as  an  ordinary  felt  hat.  Under  it 
the  Cornishman  wears  a  cap  of  calico  or  linen,  which  often  con- 
stitutes the  headgear  in  the  working  place  itself,  whilst 'the  hard 
hat  is  donned  in  going  to  and  from  the  surface.  A  few  gimlet 
holes  improve  the  Cornish  hat,  by  affording  a  little  vent  for 
the  perspiration  given  off  so  freely  when  climbing  ladders  in  warm 
shafts. 

The  Cornish  hat  is  serviceable  as  the  brim  keeps  the  neck 
dry,  and  in  sinking  very  wet  shafts  a  waterproof  flap  can  be 
added,  so  as  to  increase  the  amount  of  protection.  Lastly, 
the  lump  of  clay  used  as  a  candle-holder  can  be  easily  and 
safely  stuck  upon  the  hat,  leaving  the  miner  both  hands  free 
when  he  is  climbing  about  the  workings  by  rope,  chain  or 
ladder. 

The  British  miner,  working  upon  seams  of  stratified  ironstone, 
affects  a  leathern  cap,  which  he  wears  with  the  small  peak  turned 
towards  the  back.  It  is  far  lighter  than  the  Cornish  hat,  but  it  is 
not  capable  of  resisting  so  hard  a  blow. 

In  France   a   leathern   hat,  in   shape   like   the  Cornishman's, 


672  ORE  AND  STONE-MINING. 

is  common.    It  is  made  of  thick  solid  leather,  and  is  therefore  very 
strong  and  durable,  but  it  is  heavy  and  expensive. 

In  some  parts  of  Germany  the  miner  wears  a  brimless  hat, 
something  like  a  busby,  made  of  loose-textured  felt,  thick  enough 
to  prevent  a  tolerably  hard  knock  from  doing  any  harm,  and  yet 
porous  enough  to  admit  the  passage  of  perspiration.  In  sunless 
workings  a  brim  is  not  required  for  guarding  the  eyes,  and  in  dry 
mines  the  German  hat  with  an  undercap  of  linen  forms  a  very  suit- 
able head  covering.  It  is  light,  weighing  only  about  half  a  pound, 
and  it  can  be  folded,  which  is  an  advantage  if  one  is  travelling.  On 
the  other  hand,  its  porosity  and  its  want  of  a  brim  render  it 
unfitted  for  very  wet  places,  and  it  cannot  be  used  for  carrying  the 
candle  in  the  same  way  as  the  Cornish  hat. 

The  hat  of  the  Mansfeld  copper  miner  is  made  of  thick  black 
felt  and  weighs  half  a  pound ;  it  has  a  broad  brim  which  is  turned 
up  in  front  and  covered  with  leather.  A  piece  of  wire  sewn  on 
under  the  leather  serves  as  a  hook  for  carrying  the  lamp  on  the 
head,  though,  now  that  the  shafts  are  mostly  provided  with  cages, 
there  is  little  ladder  work  to  make  this  necessary.  The  felt  is  thick 
enough  to  save  the  head  if  struck,  and  the  brim  protects  the  neck 
from  drops  of  water.  It  is  a  light,  comfortable  and  cheap  hat. 

In  sinking  oil  wells  in  Roumania,  the  mirier  adopts  a  conical  hat, 
shaped  like  that  of  the  Chinaman,  but  made  of  tinplate,  which 
serves  to  keep  off  the  drops  of  water  and  petroleum. 

Looking  at  the  number  of  accidents  from  falls  of  roof,  to  say 
nothing  of  accidents  from  things  falling  down  shafts,  the  nature 
of  the  head-gear  adopted  by  the  miner  is  not  without  importance. 
It  is  especially  necessary  that  shaft-sinkers  should  be  careful  to 
have  suitable  hats.  An  ideal  hat  would  be  light,  but  strong,  welJ- 
ventilated,  and  with  brim  enough  to  prevent  water  from  running 
down  the  neck. 

Boots. — Turning  to  the  other  extremity  of  the  body,  it  is  fre- 
quently noticed  that  the  Cornishman,  though  careful  about  his 
head,  pays  very  little  attention  to  his  feet.  He  often  has  to 
walk  through  wet  levels,  and  knowing  that  he  cannot  reach  his 
working-place  dry-shod,  he  is  quite  content  with  any  dilapidated 
foot-gear.  Unfortunately  this  carelessness  is  sometimes  the  cause 
of  accidents,  for  men  have  been  known  to  slip  from  ladders  from 
wearing  shoes  which  did  not  give  them  a  proper  foothold. 

In  some  of  the  Welsh  ore  mines  the  clog  is  very  commonly 
worn ;  it  is  a  boot  with  wooden  soles  and  leather  "  uppers."  The 
sole  is  protected  from  too  rapid  wear  by  irons  at  the  bottom  and 
sides.  Many  miners  like  clogs,  as  the  wooden  sole  is  warmer  than 
leather,  and  consider  that  they  are  less  likely  to  slip  than  ordinary 
boots  or  shoes  in  climbing  up  and  down  ladders  or  steep 
"stopes."  I  can  well  imagine  that  the  stiff  wooden  sole 
gave  a  better  foothold  on  the  vertical  ladders  of  the  Flint- 
shire mines  years  ago  than  yielding  leather.  The  clog  has  tht 


CONDITION  OF  THE  MINER.  673 

further  merit  of  cheapness,  but  the  unbending  sole  renders 
it  therefore  less  comfortable  than  the  ordinary  foot-gear  for  much 
walking.  Men  who  use  clogs  below  ground  often  walk  to  and 
from  the  mines  in  leathern  boots  or  shoes. 

The  Festiniog  "  rockman,"  whose  working-place  lies  among 
smooth  surfaces  of  slate,  trusts  to  a  strong  laced  boot  well  shod 
with  nails  to  prevent  his  slipping,  while  he  climbs  about  chain  in 
hand.  Another  reason  for  the  strong  foot-covering  is  the  fact 
that  the  fragments  of  rock  are  often  sharp  and  cutting. 

Many  miners  in  France  still  wear  the  clumsy  but  cheap  wooden 
shoe  or  "sabot,"  whilst  in  Spain  they  have  sandals  made  of 
esparto  grass.  These  cost  only  $d.  or  3^.  per  pair,  and  last  from 
three  weeks  to  a  month.  Lastly,  when  we  travel  further  afield, 
we  find  the  hardy  miner  going  barefoot,  provided  by  nature  alone 
with  a  tongh  outer  tegument,  which  gives  him  a  better  hold  on 
rock  or  ladder  than  any  which  art  can  furnish. 

Jacket. — Little  need  be  said  about  the  clothing  of  the  worker 
at  the  surface,  save  that  where  he  is  engaged  near  machinery 
it  is  advisable  that  the  jacket  should  fit  closely.  Accidents  have 
happened  from  loose  clothing  being  blown  on  to  revolving  gearing 
or  shafting,  which  could  not  be  stopped  until  the  unfortunate 
workman  had  been  drawn  in  and  mangled. 

As  has  been  already  explained,,  it  is  necessary  from  time  to 
time  to  clean  out  the  flues  in  which  arsenic  has  collected  from 
the  calcination  of  ores  containing  mispickel.  Under  the  Special 
Rules  in  force  at  some  of  the  Cornish  mines,  the  owner  has  to 
provide  suitable  clothing  for  this  work ;  probably  the  best  is  a 
combination  suit  consisting  of  jacket  and  trousers  in  one  garment, 
such  as  is  used  for  going  into  boilers.  The  legs  of  the  trousers 
should  be  tied  round  the  ankles,  and  the  sleeves  round  the  wrists, 
in  order  to  prevent  any  particles  of  arsenic  from  finding  their 
way  to  the  skin  and  so  doing  mischief. 

2.  HOUSING. — It  may  or  may  not  fall  to  the  lot  of  the 
mine-owner  to  provide  dwellings  for  some  or  all  of  his  workmen, 
but  in  any  case  it  is  his  duty  to  interest  himself  in  the  question 
of  the  living  accommodation  for  them  and  their  families.  Even 
if  he  is  not  moved  by  considerations  of  a  humanitarian  nature,  as 
he  certainly  ought  to  be,  the  mine-owner  must  recognise  the  fact 
that  it  does  not  answer  commercially  to  let  his  men  fall  sick,  become 
prematurely  unfit  for  work  or  die  at  an  early  age  j  nor  does  it  pay 
to  have  the  working  staff  constantly  changing.  A  valuable  horse 
is  put  into  a  good  stable,  is  well  tended  and  not  overworked, 
if  the  master  wishes  to  derive  as  much  profit  as  possible  from  it ; 
and  it  cannot  be  expected  that  the  best  results  will  be  got  from 
the  miner's  labour,  unless  he  is  treated  with  at  least  as  much  con- 
sideration as  the  lower  animal.  Therefore  on  the  score  of  profit 
as  well  as  upon  the  score  of  humanity,  the  mine-owner  should 
insist  upon  proper  dwellings  being  available  for  his  men. 

2  u 


674  ORE  AND  STONE-MINING. 

When  mining  is  carried  on  in  the  midst  of  a  fairly  populous 
district,  private  enterprise  may  often  be  relied  on  for  providing 
suitable  cottages,  nevertheless  even  here  the  mine-owner  may  do 
good  by  calling  the  attention  of  the  local  authorities  to  insanitary 
dwellings  or  cases  of  overcrowding.  It  frequently  happens, 
however,  that  mines  are  worked  in  out-of-the-way  places,  where, 
at  all  events  in  the  early  days  of  the  enterprise,  there  is  a  total 
absence  or  utter  inadequacy  of  accommodation  for  the  workpeople. 
The  mine-owner  is  then  obliged  to  take  upon  his  own  shoulders 
the  burden  of  providing  dwellings.  Two  classes  may  be  erected  : 

(1)  Barracks,  which  serve  for  unmarried  men,  or  for   married 
men   whose  homes  are    not  within  the  reach  of   a  daily   walk  ; 

(2)  Cottages  for  married  couples  and  their  children. 
Barracks. — Excellent  examples    of    barracks  are  found,  for 

instance,  at  the  Mechernich  lead  and  the  Mansfeld  copper  mines, 
owned  by  two  enlightened  and  prosperous  companies.  The  large 
workmen's  hotel  at  Mechernich  is  capable  of  accommodating 
about  400  men.  The  workmen  are  perfectly  free  to  do  as  they 
like,  as  regards  living  in  the  barracks  or  not ;  but  if  they  do  live 
there,  they  must  conform  to  the  regulations. 

The  cost  of  lodging  is  yd.  per  week ;  for  this  a  man  gets  a 
comfortable  bed  with  a  spring  mattress,  and  clean  sheets  and 
blankets.  The  beds  are  such  as  I  would  sleep  in  without  hesi- 
tation. The  space  allowed  in  the  bedrooms  is  400  cubic  feet  per 
man,  and  in  winter  the  rooms  are  warmed  by  hot  air.  They 
are  kept  scrupulously  clean,  and  the  men  are  obliged  to  change 
their  working  clothes  as  soon  as  they  come  in,  and  put  on  other 
suits. 

The  men  can  be  supplied  with  their  meals  at  stated  hours  in 
the  large  dining  hall  at  low  prices,  and  boiling  water  is  always 
ready  for  them  gratis,  so  they  can  make  coffee  from  their  own 
store  if  they  like.  The  dining  hall  has  a  tiled  floor,  and  the 
tables  are  scrubbed  until  they  are  exquisitely  clean. 

The  sanitary  conveniences  are  ample  and  well  kept,  and  the 
men  can  have  warm  shower-baths  free  of  cost. 

The  mental  comforts  are  not  forgotten.  There  is  a  reading- 
room,  with  newspapers,  which  is  open  after  working  hours,  and  a 
library,  from  which  the  men  can  borrow  books. 

At  the  Mansfeld  copper  mines  the  company  have  provided  no 
less  than  nine  barracks,  capable  of  accommodating  2268  men 
and  48  females.  The  barracks  at  Eisleben,  which  will  house  350 
men,  are  represented  in  Figs.  700  and  701,  taken  from  the  long 
and  careful  report  of  Oberbergrath  Taeglichsbeck.*  The  house  is 
a  three-storey  brick  building,  with  bedrooms  for  nine,  ten,  or  eleven 
men  each.  In  accordance  with  official  regulations,  there  is  an  air 

*  "  Die  Wohnungsverhaltnisse  der  Berg-  und  Salinenarbeiter  im  Ober- 
bergamtsbezirke  Halle,  einschliesslich  der  Mansf elder  Hiittenarbeiter," 
Zeitsckr.f.  B.-  H.-  u.  S.-Wesen  im  Preuss.  Staate,  vol.  xl.  1892,  p.  44. 


CONDITION  OF  THE  MINER, 

FIG.  700. 


675 


Front  Elevation. 
FIG.  701. 


5METRES       0 


Ground  Plan. 

SCALE 

10 


20     METRES  25 


10  FEET     0 


20 


30 


40 


50 


60 


70    FEET80 


676  ORE  AND  STONE-MINING. 

space  of  350  to  400  cubic  feet  (10  to  n  cubic  metres)  per  man, 
The  rooms  are  heated  with  hot  air  in  winter,  and  there  is  a  large 
dining-hall  adjoining  the  kitchen,  in  a  separate  building,  connected 
with  the  dormitories  by  a  covered  way.  This  building  cost 
^9370,  including  a  house  for  the  steward,  who  superintends 
everything,  and  laying  on  water.  The  barracks  are  built  in 
airy  situations,  and  are  mostly  surrounded  by  gardens.  They  are 
provided  with  all  sorts  of  conveniences,  baths,  reading-rooms, 
libraries,  skittle-alleys,  &c. 

The  men  lodging  at  the  barracks  pay  the  fixed  tariff  of  gd.  per 
day  for  their  board ;  for  breakfast  each  man  gets  J  litre  of  coffee 
and  milk ;  for  dinner  ri  litre  (2  pints)  of  thick  soup  or  vege- 
tables, with  I  kil.  (4!  ozs.)  of  beef  or  pork,  weighed  after  cooking 
and  without  bone ;  and  for  supper  if  litres  (3  pints)  of  thick 
soup,  made  with  suet,  or  coffee  and  milk.  In  addition  to  this,  he 
receives  weekly  two  loaves  of  bread,  each  weighing  3  kil.  (6 '6  Ibs.), 
5  kil.  (^  Ib.)  of  butter,  and  the  same  amount  of  fat.  Those  who 
prefer  it  can  take  ham,  sausage,  or  bacon  instead  of  the  butter 
and  fat.  For  lodgings,  lights,  and  firing,  each  boarder  has  to  pay 
o'6d.  ($pf.)  per  day  in  summer  and  o'gd.  (8  pf.)  per  day  in  winter. 

Order  and  cleanliness  are  enforced  by  a  code  of  regulations, 
which  have  to  be  strictly  observed  by  all  the  boarders.  The 
rules  prescribed  for  the  barracks  at  Mansfeld,  Stassfurt,  &c.,  are 
given  at  length  by  Taeglichsbeck.* 

The  barrack  system  is  also  found  in  this  country,  especially  in 
North  Wales,  but  not  on  so  large  or  so  sumptuous  a  scale  as  in 
Germany.  In  Wales  the  men  often  sleep  two  in  a  bed,  upon  straw 
mattresses;  and,  as  a  rule,  there  is  not  a  separate  eating-room,  nor 
are  there  any  arrangements  for  supplying  meals.  One  sees  the 
men  arrive  on  a  Monday  morning,  carrying  their  provisions  for 
the  week  on  their  backs ;  and  they  cook  their  food  themselves  by 
the  common  fire  of  the  eating  and  sleeping  apartment.  Often 
there  is  no  person  provided  for  keeping  the  rooms  clean,  and  the 
disorder  and  discomfort  are  consequently  great.  Sheer  ignorance 
is  sometimes  the  cause  of  some  of  the  evils.  I  have  seen  bunks 
prepared  for  2 1  men  in  a  room  without  a  window  or  a  chimney, 
and  containing  only  2200  cubic  feet  of  space — i.e.,  about  one-third 
of  the  smallest  amount  which  sanitarians  would  consider  requisite. 
If  mining  companies  build  barracks,  they  should  employ  some  one 
acquainted  with  the  rudiments  of  sanitary  science  to  design  them  ; 
the  eating-room  should  be  separate  from  the  dormitories,  and  the 
house  should  be  kept  clean  and  tidy. 

The  most  extensive  development  of  the  barrack  system  in  any 
British  possessions  is  at  the  Kimberley  diamond  mines,  where 
the  particular  exigencies  of  the  case  have  led  to  a  modification 
which  is  not  found  elsewhere.  One  great  diificulty  of  diamond 

*  Op.  cit.  p.  170. 


CONDITION  OF  THE  MINER.  677 

mining  in  the  early  days  was  the  prevention  of  thefts  of  valuable 
stones.  Gems  of  great  value  can  be  so  easily  secreted  about  the 
person,  or  indeed  swallowed,  that  the  mine  owner  could  be,  and 
was,  robbed  with  little  fear  of  detection.  It  is  true  that  since  the 
passing  of  the  Illicit  Diamond  Act,  the  disposal  of  stolen  diamonds 
has  become  more  difficult,  but  the  protection  afforded  by  this 
statute  does  not  entirely  suffice.  The  plan  now  adopted  with  the 
native  miners  is  to  confine  them  for  the  length  of  their  contract, 
often  three  months,  and  not  allow  them  on  any  pretext  to  leave 
the  company's  premises.  They  go  straight  from  their  barracks 
to  the  mine  by  a  securely  enclosed  way,  and  return  to  them  as  soon 
as  work  is  over.  The  barracks  consist  of  one-storey  buildings,  made 
of  corrugated  iron,  arranged  so  as  to  form  the  four  sides  of  a 
large  square,  and  divided  into  rooms  holding  about  twenty  natives 
each.  The  "  compound,"  *  as  it  is  called,  often  covers  several 
acres ;  and  it  is  surrounded  by  a  high  iron  fence  10  feet  from  the 
building.  The  natives  can  procure  all  the  necessaries  of  life  from 
a  store  within  the  compound,  whilst  food  and  water  are  supplied 
free.  A  large  swimming  bath  enables  them  to  enjoy  a  dip  when- 
ever they  like.  If  perchance  a  man  falls  ill,  he  is  taken  to  a 
hospital,  also  belonging  to  the  company. 

Of  course,  this  system  would  not  find  favour  with  European 
miners,  who  would  resent  the  enforced  confinement  and  regard  it 
as  an  irksome  imprisonment ;  but  the  native,  with  fewer  wants, 
is  quite  content  to  put  up  with  the  temporary  loss  of  liberty  for 
the  sake  of  getting  good  wages. 

Cottages. — Enough  has  been  said  about  barracks,  and  we  may 
now  pass  on  to  cottages  for  families.  At  many  of  the  collieries 
of  this  and  other  countries,  great  attention  has  been  paid  to  the 
erection  of  workmen's  villages,  and  a  large  amoum;  of  capital  has 
been  sunk  in  providing  comfortable  and  convenient  dwellings. 
It  is  an  advantage  to  the  mine-owner  to  have  his  men  on  the 
spot,  coming  to  their  work  without  the  fatigue  of  a  long  walk ; 
and  it  is  a  benefit  to  the  man  to  have  his  home  within  easy  reach. 
When,  therefore,  the  preliminary  explorations  and  workings  have 
revealed  the  existence  of  enough  mineral  to  supply  a  mine  for  a 
number  of  years,  a  company  is  thoroughly  justified  in  spending 
money  upon  houses. 

Figures  702  to  705  represent  the  type  of  miner's  cottage  lately 
erected  by  Mr.  Emerson  Bainbridge  for  the  Bolsover  Collieries  in 
Nottinghamshire.  It  will  be  seen  that  each  cottage  has  a  good 
living-room  and  scullery  on  the  ground  floor,  two  good  bedrooms 
on  the  first  floor,  and  an  attic  above. 

Many  a  workman,  however,  would  rather  be  his  own  landlord, 
and  not  feel  the  restraint  of  living  in  a  cottage  belonging  to  the 
company,  because  he  may  have  to  quit  it  if  he  goes  to  work  at 

*  Second  Annual  Report  of  the  De  Beers  Consolidated  Mines,  Limited,  for 
the  year  ended  March  1890,  p.  23. 


678 


ORE  AND  STONE-MINING. 


another  mine,  or  because  he  feels  the  natural  ambition  of  wishing- 
to  own  a  house  himself.  In  order  to  encourage  this  very  laudable- 
object,  mining  companies  often  make  it  easy  for  the  workman  to 
buy  his  cottage  by  small  instalments,  and  they  thus  gather  around 
their  mines  a  number  of  small  householders,  who  are  less  likely 
to  encourage  disturbances  than  men  who  have  no  special  interest 
in  the  preservation  of  order.  To  the  workman  there  are  advantages- 


FIG.  702. 


FIG.  703. 


CROUrtD  PLM 


as  well  as  disadvantages ;  if  the  cottage  belongs  to  him,  he  has  a 
feeling  of  independence,  and  he  does  not  mind  spending  money  to 
embellish  or  improve  it,  which  he  would  not  do  if  it  were  the  pro- 
perty of  somebody  else.  The  purchase  may  be  a  wise  and  profitable 
one,  if  he  feels  pretty  sure  that  he  is  going  to  spend  all  his  days  in 
one  place ;  but  this  fixedness  to  one  district  cannot  always  be 
assured  or  advised.  Wages  may  be  better  in  an  adjoining  county 
or  in  some  foreign  land,  mining  may  decline  at  home  or  entirely 
cease,  and  a  move  may  become  a  necessity,  with  no  chance  of 
selling  the  cottage  property.  Under  such  circumstances  the 
earnings  spent  in  buying  a  cottage  will  have  been  badly  invested. 


CONDITION  OF  THE  MINER. 


679 


It  also  happens  that  during  a  period  of  high  wages,  a  man  is 
tempted  to  arrange  for  the  purchase  of  his  house  with  one  of  the 
numerous  building  societies,  and  he  agrees,  for  instance,  to  pay 
£i  per  month  for  ten  years,  at  the  end  of  that  time  becoming 
the  owner  of  a  house  worth  £,120.  If  his  wages  are  ^7  a 
month  he  can  manage  the  monthly  instalments  without  difficulty; 
but  let  wages  drop  to  ^£5,  and  he  will  find  it  far  less  easy  to  keep 
up  his  payments. 

As  an  example  of  the  manner  in  which  workpeople  are  housed, 
I  will  again  extract  some  figures  from  Taeglichsbeck's  report.* 
For  the  Halle  district  he  gives  the  following  numbers  and  pro- 
portions : 


-  — 

Kind  of  Dwelling-house  and  Percentage  of 
the  Total  Number  of  Persons. 

Rent  free, 
but  Eent 
reckoned 
as  part 
of  Wages. 

Living  in 
their  own 
Houses. 

Living  in 
hired 
Houses. 

Living  in 
Barracks, 
&c. 

Workmen. 
Private  works  (40,372  persons) 
Government  works  (3274  persons)  . 
Officials. 
Private  works  (1196  persons) 
Government  works  (122  persons)    . 

o-53% 

0-36% 
45-82% 

7377% 

2r85% 
27-92% 

17-23% 
9-84% 

70"II% 
71-14% 

36-95% 
I6'39% 

7-51% 
0-58% 

He  further  shows  that  25  per  cent,  of  the  persons  employed  at 
the  Mansf  eld  copper  mines  are  living  in  their  own  houses,  of  which 
nearly  one  quarter  have  been  purchased  with  the  assistance  of  the 
Company. 

Before  concluding  this  subject  of  housing,  a  word  may  be  said 
about  the  "  dries,"  or  changing  houses,  which  have  to  be  provided 
at  mines  under  the  Metalliferous  Act,  when  more  than  twelve 
persons  are  employed  below  ground.  Such  a  house  is  very 
necessary  when  the  men  come  up  wet  and  dirty,  and  often  soaked 
with  perspiration  from  working  in  hot  places  or  from  climbing 
long  runs  of  ladders.  They  then  change  all  their  clothes,  and 
leave  them  to  be  dried  ready  for  use  on  the  following  day.  One 
of  the  best  modes  of  heating  a  "  dry  "  is  by  steam  ;  the  shell  of 
an  old  boiler  is  placed  along  the  centre  of  the  house  and  is  supplied 
with  steam  from  any  convenient  source.  Owing  to  the  large 
surface  of  the  shell  the  room  is  speedily  heated,  and  the  clothes 
hung  about  it  are  quickly  dried.  The  water  condensing  from 
the  steam  may  be  drawn  off  by  a  cock  and  used  for  washing 
purposes.  Figs.  706  and  707  represent  the  changing  house  erected 
at  Levant  Mine  in  Cornwall  by  Mr.  Eustice,  which  has  the 
advantage  of  being  put  into  communication  with  the  man-engine 
shaft  by  a  passage  and  staircase,  so  that  the  men  stand  no  risk  of 
*  Op.  cit.  p.  7. 


68o 


ORE  AND  STONE-MINING. 


CONDITION  OF  THE  MINER. 


681 


exposure  to  the  fierce  breezes  coming  straight  off  the  Atlantic, 
which  might  sometimes  be  trying  after  the  underground  warmth. 
It  is  heated  by  rows  of  hot-water  pipes. 

The  floor  of  the  "  dry  "  should  be  made  of  cement  and  not  of 
boards,  to  permit  the  application  of  the  hose  for  washing  it. 
Benches  and  lockers  should  be  removable  in  order  to  facilitate 
the  cleaning,  which  is  frequently  necessary,  considering  the 
amount  of  dirt  which  cannot  fail  to  accumulate  in  such  a 
place.  A  wooden  floor  has  the  disadvantage  that  the  boards  are 
sure  to  shrink  under  the  constant  warmth,  and  when  once  full  of 

FIG.  708. 


gaping  chinks  it  can  never  be  effectually  cleaned  ;  besides,  there 
is  the  danger  from  fire,  either  from  matches  left  carelessly  about 
or  from  the  men  smoking  in  a  place  where  the  wood  gets  as  dry 
as  tinder.  The  walls  should  be  whitewashed  at  regular  and 
frequent  intervals,  in  order  to  keep  the  place  thoroughly  sweet. 

It  is  not  difficult  to  give  the  miner  the  luxury  of  a  shower- 
bath  at  a  small  cost,  and  it  seems  to  me  far  better  that  the  miner 
should  change  and  perform  all  necessary  ablutions  at  the  mine, 
than  go  home  in  his  underground  clothes,  and  depend  upon  the 
resources  of  his  cottage  for  washing  himself  and  drying  his  working 
apparel. 

At  the  Anzin  collieries,  in  the  North  of  France,  a  large  number 
of  shower-baths  (Fig.  708),  are  provided  at  the  different  shafts,  so 


682  ORE  AND  STONE-MINING. 

that  the  men  have  not  to  wait  for  their  turn.  The  Anzin  arrange- 
ments are  excellent,  and  might  be  copied  with  advantage  at 
some  of  our  mines. 

3.  EDUCATION. — The  school  education  may  be  of  two 
kinds,  general  and  technical.  In  this  and  other  countries,  where 
the  primary  education  is  free,  the  mine-owner  need  not  concern 
himself  with  providing  schools  and  teachers ;  but  where  the  State 
does  not  take  this  paternal  care  of  the  rising  generation,  a  certain 
responsibility  for  the  young  is  often  felt  by  the  shareholders  of 
the  mining  companies,  and  they  endeavour  to  equip  the  children 
of  their  workmen,  at  all  events,  with  the  three  R/s. 

For  carrying  on  mining,  it  is  not  sufficient  merely  to  provide 
strong  bones  and  well-developed  muscles;  there  must  also  be 
brains,  or,  in  other  words,  no  matter  how  good  the  miners  are, 
their  work  must  be  directed  by  trained  engineers  and  competent 
foremen.  The  latter  may  well  be  recruited  from  among  the  actual 
working  men,  who  should  have  some  general  knowledge  of  science 
and  some  special  training  in  the  various  branches  of  their  pro- 
fession. 

This  scientific  and  technical  training  is  frequently  provided  by 
the  large  foreign  mining  companies  at  their  own  expense.  The 
best  of  the  young  men  attend  classes  out  of  working  hours,  and 
thus  manage  to  carry  on  their  lecture-room  teaching  hand  in 
hand  with  the  practical  instruction  which  they  are  acquiring  in  the 
mine  itself. 

In  this  country  the  education  of  the  young  miner  is  largely 
aided  by  classes  held  in  the  evenings,  under  the  auspices  of  the 
Science  and  Art  Department,  the  City  and  Guilds  of  London 
Institute,  and  some  of  the  County  Councils.  The  energetic  and 
ambitious  workman  can  nowadays  obtain  instruction  in  mathe- 
matics, mechanics,  chemistry,  physics,  geology,  the  principles  of 
mining,  ore-dressing,  assaying  and  mine-surveying  in  any  large 
town  and  often  in  outlying  villages.  To  those  preparing  to  pass 
the  examination  for  a  certificate  under  the  Coal  Mines  Act,  these 
classes  are  very  valuable. 

The  success  of  local  schools  and  classes  depends  a  good  deal 
upon  the  attitude  assumed  by  the  managers  of  mines  in  the 
neighbourhood.  If  educational  work  is  pooh-poohed  by  the 
masters,  the  men  follow  suit  and  the  teaching  languishes.  On 
the  other  hand,  if  the  head-piece  of  the  school  is  one  of  the  chief 
mining  engineers  of  the  district,  pupils  flock  to  the  lecture-rooms 
and  laboratories,  and  success  is  almost  a  certainty.  By  forming 
and  encouraging  these  local  schools  or  classes,  owners  and 
managers  of  mines  are  not  only  promoting  the  welfare  of  the 
rising  generation  around  them,  but  they  are  at  the  same  time 
doing  good  to  mining  generally,  and  are  contributing  to  the  intro- 
duction of  the  most  improved  methods  of  extracting  minerals. 
Just  as  the  success  of  an  army  depends  largely  upon  its  trained 


CONDITION  OF  THE  MINER.  683 

non-commissioned  officers,  so  the  prosperity  of  a  mining  enter- 
prise is  largely  influenced  by  the  competency  of  the  foremen ; 
many  of  them  by  virtue  of  their  talent  and  industry  rise  from 
the  ranks  and  become  excellent  managers  of  mines. 

The  training  of  foremen  must  not  be  carried  on  to  the  exclusion 
of  all  thought  for  their  sisters,  who  will  make  better  wives  and 
mothers  if  they  receive  some  instruction  in  the  arts  which  belong 
more  particularly  to  the  domain  of  women,  such  as  housekeeping, 
cookery  and  nursing.  Teaching  of  this  kind  becomes  more  than 
ever  necessary  in  localities  where  females  are  largely  employed  on 
the  dressing  floors,  for  then  the  girls  fail  to  receive  that  practical 
training  in  household  work,  which  would  otherwise  fall  to  their 
lot,  if  they  entered  domestic  service,  or  assisted  their  mothers  in 
their  own  homes. 

4.  SICKNESS.— At  first  sight  it  might  be  supposed  that 
milling  is  necessarily  an  unhealthy  occupation,  that  confined 
for  hours  in  dark  and  gloomy  passages  a  man  cannot  keep  well 
and  strong.  Stubborn  facts  and  figures  show  that  a  general  asser- 
tion of  this  kind  is  not  well-founded ;  but  nevertheless  the  miner 
does  suffer  in  some  cases  from  diseases  inherent  to  his  calling, 
and  these  can  be  best  combated  if  their  causes  are  thoroughly 
understood  by  all  who  are  connected  with  mining  operations. 

The  diseases  to  which  miners  are  most  liable  have  been  care- 
fully studied  by  Dr.  Ogle,*  who  with  infinite  pains  has  worked 
out  the  death-rates  for  mining,  as  well  as  for  other  occupations, 
from  the  figures  contained  in  the  national  register  of  deaths. 
Of  course  it  is  very  difficult,  if  not  impossible,  in  comparing  the 
death-rate  of  the  miner  with  that  of  some  other  working  man, 
to  say  precisely  how  much  of  the  difference  is  due  to  the  effect  of 
the  calling.  The  miner  is  to  a  certain  extent  a  picked  man  ;  the 
weaklings  of  a  family  do  not  go  to  work  underground,  conse- 
quently in  the  race  of  life  the  miner  has,  so  to  say,  a  start,  which 
ought  ceteris  paribus  to  make  him  a  winner.  The  actual  death- 
rates  of  some  occupations  are  given  in  the  table  on  p.  684, 
extracted  from  Dr.  Ogle's  much  more  complete  list.  The  com- 
parative mortality  figure  affords  the  easiest  means  of  contrasting 
the  differences  between  the  various  callings  as  regards  healthiness. 
The  figure  1000  represents  the  total  number  of  deaths  among  a 
certain  number  of  male  persons  between  the  ages  of  25  and  6 
for  the  whole  of  England ;  then  taking  the  same  number  o 
persons  in  any  particular  calling  at  the  same  ages,  Dr.  Ogle 
has  calculated  the  corresponding  number  of  deaths.  The  lower 
the  figure,  the  healthier  the  occupation.  In  very  healthy  dis- 
tricts the  mortality  figure  is  as  low  as  804,  that  of  the  agricul- 
tural labourers  is  only  701.  If  we  take  miners,  we  do  not  find 
a  high  mortality  figure  for  the  collier,  nor  for  the  ironstone 

*  Supplement  to  the  Forty-ffth  Annual  Report  of  the  Registrar  of  Births] 
Deaths  and  Marriages  in  England.  London,  1885,  pp.  xxv.,  et  seq. 


684 


ORE  AND  STONE-MINING. 


miner ;  but  the  figure  for  Cornwall  is  appalling.  Mining  coal 
and  ironstone  appears  to  be  less  fatal  to  life  than  baking  bread  or 
making  boots  and  shoes. 


Mean  Annual  Death-rates  per 

03    3 

>  6C    . 

looo  living. 

|B? 

1860-1-1871. 

1880-1-2. 

If 

OCCUPATION. 

Years  of  Age. 

Years  of  Age. 

Years  of 
Age. 

25-45- 

45-65- 

25-45- 

45-65. 

25-65- 

All  males      .... 

II'27 

23-98 

10-16 

25-27 

IOOO 

Males  in  selected  healthy  ] 
districts                          f  ' 

— 

8-47 

1974 

804 

Baker   .... 

1072 

26-39 

870 

26-12 

958 

Blacksmith  . 

10-07 

23-88 

9-29 

25-67 

973 

Boilermaker          .         .          • 

— 

— 

9-27 

26-65 

994 

Builder,  mason,  bricklayer 

II"43 

27-16 

9-25 

25-59 

969 

Butcher 

13-19 

28-37 

I2"l6 

29-08 

1170 

Carpenter 

9  '44 

21-36 

777 

21-74 

820 

Fisherman    ... 

11-26 

'5  '84 

8-32 

1974 

797 

Miner,  coal  . 





7-64 

25-11 

891 

,,      ironstone  . 

— 

— 

8-05 

21-85 

834 

„      Cornwall  . 

11-94 

41-73 

14-77 

53*69 

1839 

Labourer,  agricultural  . 

17-68 

701 

Plumber,  painter,  glazier 

12-48 

34-66 

11-07 

32'49 

1  202 

Quarrier,  stone  and  slate 

10-88 

28-67 

9'95 

31-04- 

1  122 

Tailor   .         .        .        .      " 
Shoemaker   . 

12-92 
10-39 

22-30 

10-73 

26-47 
23-36 

1051 
921 

The  diseases  inherent  to  the  miner's  calling  are  due  to  the 
following  causes : 

Breathing  a  polluted  atmosphere. 
Excessive  ladder  climbing. 
Working  in  constrained  positions. 
Exposure  to  heat  and  cold. 
Working  in  compressed  air. 

Of  these  various  causes  the  first  is  undoubtedly  by  far  the  worst : 
it  brings  on  phthisis  and  other  diseases  of  the  respiratory  organs. 
There  is  nearly  six  times  as  great  a  mortality  from  these  diseases 
among  Cornish  miners  as  there  is  among  fishermen.  The 
manner  in  which  the  air  of  mines  is  polluted  has  been  explained 
in  the  chapter  upon  Ventilation — viz.,  by  the  breathing  of  the  men 
and  animals  in  the  pit,  the  combustion  of  lamps  or  candles,  exhala- 
tions of  decaying  timber,  smoke  of  explosives,  natural  emanations 


CONDITION  OF  THE  MINER.  685 

of  gases,  and  dust.  It  is  the  opinion  of  the  best  qualified  judges 
that  dust  is  largely  responsible  for  the  respiratory  ailments  from 
which  the  miner  so  often  suffers.  The  difference  between  the 
atmosphere  of  a  mine  and  that  of  the  external  atmosphere  is  often 
made  very  plain  by  the  state  of  the  nostrils  after  a  few  hours 
spent  in  underground  workings;  it  is  found  that  they  have 
strained  off  a  part  of  the  solid  particles  floating  about  in  the  air 
of  the  mine,  and  the  amount  so  arrested  will  serve  as  some  gauge 
of  the  quantity  inhaled.  Besides,  men  commonly  breathe  a  great 
deal  through  the  mouth,  and  lose  the  benefit  of  their  natural 
air- filter. 

The  dust  acts  mainly  mechanically,  but  in  a  few  exceptional 
cases  its  evil  effects  are  due  also  to  poisonous  chemical  properties. 
The  mechanical  action  is  at  first  an  irritation  of  the  delicate  lining 
membrane,  and  then  the  particles  make  their  way  into  the  tissues, 
choke  them  and  harden  them,  and  so  render  them  unfit  for 
allowing  the  chemical  action  of  the  air  upon  the  impure  venous 
blood  which  is  necessary  to  life.  The  diseases  caused  by  the 
inhalation  of  dust  in  this  way  are  bronchitis,  shortness  of  breath, 
asthma  and  consumption. 

A  large  proportion  of  the  dust  is  produced  in  the  process  of 
boring  holes  for  blasting  in  an  upward  direction.  If  the  hole  has 
a  downward  inclination  the  miner  puts  water  in,  which  not  only 
prevents  any  dust,  but  also  renders  his  work  easier  by  allowing  the 
edge  of  the  tool  to  act  more  fairly  against  the  rock.  When,  on  the 
other  hand,  the  miner  is  boring  upwards,  the  dust  is  scraped  out 
or  falls  out,  and  though  the  coarsest  particles  may  at  once  drop  to 
the  ground,  the  very  fine  and  light  ones  float  about,  and  produce  a 
cloudy  and  noxious  atmosphere.  If  machine  drills  are  employed, 
the  amount  of  dust  produced  in  a  given  time  is.  of  ten  considerable, 
as  will  be  instantly  recognised  by  any  one  dressed  in  a  dark  suit 
who  stands  by  one  of  these  machines  while  it  is  working  in  dry 
ground. 

Prevention  is  better  than  cure,  and  the  evil  consequences  can  be 
averted  by  forcing  a  jet  of  water  into  the  hole  during  the  boring 
operations.  The  jet  may  be  produced  either  by  allowing  the  com- 
pressed air  to  act  upon  the  surface  of  a  tank  containing  water,  or 
by  bringing  down  a  supply  in  a  pipe  from  a  tank  situated  at  a 
higher  level  ;  keeping  the  sides  of  the  level  moist  is  another 
precaution,  the  particles  of  dust  wafted  against  the  wet  sur- 
face are  caught,  like  flies  upon  sticky  paper,  and  so  rendered 
harmless. 

Some  of  the  dust  arises  from  the  rock  being  broken  up  in  the 
process  of  blasting,  and  some  comes  from  the  explosive  itself, 
if  it  consists,  for  instance,  of  infusorial  earth  mixed  with  nitro- 
glycerine. 

A  fine  spray  is  very  effective  in  laying  the  dust  and  fumes  pro- 
duced by  blasting,  and  an  easy  method  of  producing  it  is  to 


686  ORE  AND  STONE-MINING. 

turn  a  jet  of  compressed  air  into  a  pipe  supplied  with  water.* 
An  appliance  of  this  kind  is  specially  desirable  when  the  blast- 
ing in  an  "end"  is  done  by  volleys,  when  the  miner  has  to  walk 
into  the  smoke  of  one  blast  in  order  to  charge  another  set  of 
holes.  Some  men  make  use  of  a  sponge  as  a  respirator  while 
exposed  to  the  dust  and  fumes,  and  no  doubt  with  good  effects  ; 
but  it  is  well  to  delay  the  return  as  long  as  possible,  unless  the 
•"  end  "  is  provided  with  such  an  apparatus  as  Teague's  ventilator, 
which  speedily  withdraws  all  noxious  fumes  from  the  working 
place.  If  it  is  necessary  in  some  particular  case  to  go  into  an 
"end"  full  of  smoke,  the  harmful  effects  may  be  reduced  by 
making  use  of  Nature's  respirator,  namely,  the  nose,  and  not 
breathing  at  all  through  the  mouth. 

Dusts  which  have  a  poisonous  effect  are  those  of  certain  minerals 
•containing  arsenic,  lead  and  mercury. 

According  to  Dr.  Harting  and  Dr.  Hesse,f  cancer  in  the  lungs 
is  not  uncommon  among  the  men  working  in  the  cobalt  mines  of 
Schneeberg  in  Saxony,  and  they  ascribe  the  disease  to  dust 
containing  arsenic  in  combination  with  cobalt,  which  produces  a 
permanent  chemical  irritation  in  the  delicate  air-passages.  It  seems 
to  be  mainly  the  mineral  speiscobalt  or  smaltite  (CoAs2)  which  is 
the  source  of  the  disease ,  the  cobalt  minerals  containing  sulphur 
in  addition  to  the  arsenic  are  far  less  poisonous,  as  they  are  less 
readily  decomposed.  When  one  reflects  how  soon  cobalt  bloom, 
the  hydrated  arseniate  of  the  metal,  is  formed  upon  the  ores  in  a 
damp  atmosphere,  it  is  not  surprising  that  a  similar  action  should 
go  on  with  minute  particles  of  smaltite  imbedded  in  the  lung 
tissue,  and  eventually  set  up  a  considerable  amount  of  irritation. 

Far  more  dangerous  than  the  dust  of  arsenical  minerals  under- 
ground, are  the  fumes  produced  in  roasting  ores  containing  mis- 
pickel,  a  process  which  goes  on  in  many  tin  mines  and  some  gold  and 
copper  mines.  Particles  of  arsenious  acid  attach  themselves  to  the 
skin,  in  places  where  it  is  moist  from  perspiration,  and  produce 
nasty  sores,  whilst  those  which  enter  the  body  give  rise  to  various 
disturbances  of  the  digestive  organs.  The  best  means  of  avoiding 
the  ills  due  to  arsenic  have  been  pointed  out  by  Hirt  J  at  some 
length.  Only  thoroughly  healthy  men  should  be  allowed  to  work 
in  places  where  there  is  danger  from  arsenic,  and  they  should  be 
relieved  at  regular  intervals.  Bottles  of  hydrated  oxide  of  iron, 
in  the  form  of  an  emulsion  should  be  kept  in  readiness,  both  as  a 
preventative  and  an  antidote.  The  men  must  be  compelled  to 
exercise  the  greatest  cleanliness,  and  when  exposed  to  the  dust  and 
vapours  should  cover  the  mouth  with  a  dry  cloth.  Arsenical  sores 

*  Reports  of  H.  M.  Inspectors  of  Mines  for  the  Year  1879,  p.  527. 

t  "Der  Lungenkrebs,  die  Bergkrankheit  in  den  Schneeberger  Gruben." 
Etdenberg's  Vierteljahrsschrift  fur  gerichtliche  Medicin.  Neue  Folge,  xxx. 
Band,  p.  296,  Berlin,  1879. 

£  Arbeiter-Schutz,,  Leipsic,  1879,  P-  I3I« 


CONDITION  OF  THE  MINER.  687 

should  be  plastered  over  with  fuller's  earth  moistened  with  water 
and  hydrated  oxide  of  iron ;  strong  drinks,  especially  brandy, 
must  be  avoided,  but  milk  and  greasy  soups  help  to  resist  the 
poison. 

In  an  ordinary  lead  mine,  where  the  ore  consists  entirely  or 
almost  entirely  of  galena,  plumbism  is  rarely  heard  of ;  but 
when  the  ore  is  cerussite,  a  different  state  of  things  arises 
and  the  disease  may  be  rife.  It  is  well  known  that  the  arti- 
ficial carbonate,  the  white  lead  of  commerce,  produces  poisoning 
among  painters,  so  much  so  indeed  that  one  of  the  ailments  due 
to  lead  is  known  as  "  painters'  colic ; "  it  cannot  therefore  surprise 
us,  when  mere  handling  is  injurious,  that  breathing  a  lead-laden 
atmosphere  should  likewise  be  pernicious.  Plumbism  among 
miners  has  probably  never  been  so  prevalent  as  in  the  Broken 
Hill  district  in  New  South  Wales,  where  some  of  the  ore  in  the 
shallow  levels  is  a  pulverulent  earthy  carbonate  of  lead.  According  to 
published  accounts,*  the  state  of  things  must  have  been  very  bad  in- 
deed comparatively  lately.  Miners  suffered  more  than  the  smelters, 
but  even  the  ore-pickers  were  not  exempt  from  the  malady.  From 
this  fact  we  may  conclude  that  lead  may  have  entered  the  system 
in  some  cases  by  eating  food  with  dirty  fingers,  or,  as  suggested  by 
the  writer  of  the  article  alluded  to,  from  smoking  a  pipe  filled  with 
tobacco  rubbed  in  a  leady  hand.  The  baneful  effects  have  been 
reduced  by  not  allowing  the  men  to  work  very  long  at  one  time 
in  the  parts  of  the  mine  where  the  soft  carbonate  occurs.  The 
managers  arrange,  for  instance,  that  a  man  shall  take  one  fort- 
night at  mining  the  earthy  cerussite ;  the  next  fortnight  he  is  put 
to  work  at  the  surface  and  made  to  quarry  the  ironstone — i.e.,  the 
ferruginous  outcrop  of  gossan,  which  is  used  as  a  flux  at  the 
smelting  works  ;  and  then  he  takes  a  fortnight  underground 
in  mining  the  kaolin  ore,  which  consists  largely  of  kaolin  and 
chloride  of  silver,  and  has  no  deleterious  effect  upon  the  men,  or 
at  all  events  does  not  cause  lead-poisoning. 

The  precautions  to  be  adopted  against  plumbism  at  mines  of 
this  description  are  :  ample  ventilation,  laying  the  dust  as  far 
as  possible  by  a  spray  of  water,  and  the  strictest  cleanliness.  The 
mine-owner  should  do  his  share  by  giving  the  men  every  possible 
convenience  for  washing  themselves  and  changing  their  working 
clothes,  but  no  amount  of  forethought  on  his  part  will  suffice  to 
prevent  the  evil  entirely,  if  the  men  fail  to  avoid  every  chance  of 
defiling  their  food  or  tobacco  by  lead  ore. 

Working  in  the  quicksilver  mines  is  found  to  be  unhealthy, 
and  the  men  suffer  from  mercurial  poisoning  unless  special 
precautions  are  taken.  Thus,  at  Almaden,  even  if  the  ventilation 
is  good,  the  miner  cannot  work  more  than  four  to  four  and  a  half 
hours  a  day,  nor  can  he  work  more  than  seven  or  eight  days  in  a 

*  "  Lead  Poisoning,"  The  Australian  Mining  /Standard,  vol.  vi.,  1891, 
p.  13,  and  Report  of  Board  of  Inquiry  at  Broken  Hill,  Sydney,  1898. 


688  ORE  AND  STONE-MINING. 

month  without  injuring  his  health  very  rapidly.*  Ifc  is  true  that 
the  miners  suffer  less  than  the  smelters,  which  is  the  reverse  of 
what  happens  at  Broken  Hill,  and  the  explanation  of  this  is  that 
mercurial  poisoning  is  mainly  due  to  the  vapour  of  the  metal.  At 
Almaden  some  of  the  mercury  exists  in  the  native  state  and  is 
supposed  to  sublime  slowly ;  t  but  even  at  Idria,  where  there  is 
no  native  mercury,  where  the  ore  is  less  rich  than  at  Almaden, 
and  the  ventilation  excellent,  the  men  work  only  four  hours  at  a 
stretch — i.e.,  four  hours  in  the  morning  and  four  in  the  afternoon, 
with  an  interval  of  rest  of  four  hours. 

The  symptoms  of  mercurial  poisoning  noticed  at  Almaden  are  : 
inflammation  of  the  mouth,  salivation  and  loss  of  teeth,  shiver- 
ings,  gradual  and  general  wasting  away. 

Excessive  ladder-climbing  has  long  been  pointed  out  by  medical 
men  as  a  cause  of  disease.^  If  the  heart  is  over-stretched  day 
after  day  and  year  after  year,  it  becomes  dilated,  loses  some  of 
its  contractile  power,  and  is  therefore  less  capable  of  performing 
its  pumping  action  properly.  The  miner  who  for  years  has  had 
to  descend  and  ascend  by  ladders  in  deep  mines,  will  generally 
be  found  to  have  a  feeble  heart  and  weak  pulse  on  this  account. 
Young  miners  should  be  careful  to  avoid  the  over-exertion  caused  by 
climbing  with  unnecessary  haste.  In  these  days  of  excellent  steel 
wire  ropes  for  winding  men  up  in  cages,  it  is  perfectly  absurd 
that  a  miner  should  be  condemned  to  the  treadmill  toil  of  ladder- 
climbing,  which  has  nothing  to  be  urged  in  its  favour.  The 
shareholder  has  to  pay  for  an  unprofitable  form  of  labour,  his 
mine  is  conducted  with  less  supervision  than  there  would  be  if 
access  to  the  workings  were  easier,  whilst  the  unfortunate  miner 
suffers  in  health  and  strength.  When  a  mine  reaches  a  depth  of 
i  oo  yards  the  owner  should  introduce  means  of  raising  and  lower- 
ing the  men  mechanically  without  fatigue. 

It  is  easy  to  conceive,  when  a  man  is  working  continuously 
for  years  in -a  constrained  position,  that  certain  muscles  will  be 
stunted  in  their  growth  from  want  of  use,  and  that  others  will  be 
abnormally  enlarged  from  over-use,  and  so  cause  a  distortion  of 
the  body.  This  happens  to  a  slight  extent  with  the  men  working 
on  the  thin  bed  of  copper  shale  of  Mansfeld. 

The  disease  of  the  eye  known  as  nystagmus  has  been  noticed 
among  colliers.  A  person  suffering  from  nystagmus  sees  objects 
apparently  moving  in  a  circle ;  gas  lights  in  a  room,  for  instance, 
seem  to  dance  ;  the  man  also  suffers  from  headache  and  giddiness, 

*  Kuss,  "  Note  sur  1'etat  actuel  de  la  mine  et  de  1'usine  d' Almaden," 
Annales  des  Mines,  8me.  serie,  tome  xi.,  p.  138. 

t  Eng.  Min.  Jour.,  vol.  xlvi.,  1888,  p.  435. 

I  Dr  Peacock,  "  Medical  Keport  on  the  Condition  of  Miners  " ;  Bankart, 
"Medical  Report  on  the  Condition  of  Miners  in  Cornwall  and  Devon"  ; 
Appendix  B.  to  the  Eeport  of  the  Commissioners  appointed  to  Inquire  into  the 
Condition  of  all  Mines  in  Great  Britain  to  which  the  Provisions  of  the  Act 
23  &  24  Viet.  cap.  151  do  not  apply.  P.  7  and  p.  95,  London,  1864. 


CONDITION  OF  THE  MINER.  689 

and  the  eyeballs  are  noticed  to  oscillate  or  rotate.  According 
to  Snell  *  the  men  most  afflicted  with  nystagmus  are  those  who 
have  to  work  lying  on  their  side;  owing  to  this  unnatural 
position  the  muscles  of  the  eyes  are  unduly  strained  and  suffer 
from  overwork.  Mere  work  upon  the  side  is  in  some  districts 
insufficient  to  set  up  the  disease,  for  during  a  period  of  six  years 
only  two  cases  were  noticed  among  the  14,000  Mansfeld  copper 
miners.  As  these  men  use  open  lights,  it  is  not  unnatural  that 
nystagmus  should  have  been  ascribed  by  some  doctors  to  the 
insufficient  illumination  afforded  by  the  safety  lamp.  Snell 
combats  this  hypothesis,  and  cites  cases  of  the  disease  in  persons 
who  have  never  used  a  safety  lamp ;  therefore  the  want  of  a 
better  light  cannot  be  the  only  cause.  To  a  layman  it  seems 
quite  possible  that  both  views  may  be  correct;  the  two  sets  of 
doctors  agree  that  the  disease  is  produced  by  over-strain  of  the 
ocular  muscles,  and  as  either  of  the  two  causes  appears  capable 
of  occasioning  such  a  strain,  why  should  there  be  a  difficulty  in 
admitting  both  explanations  ? 

The  great  heat  of  the  workings  on  the  Comstock  t  lode  has 
been  mentioned  in  the  early  part  of  this  chapter,  and  many  men 
are  said  to  have  lost  their  lives  from  it,  being  picked  up  dead 
in  the  mine.  New-comers  suffered  more  than  the  old  hands. 
There  was  also  the  danger  of  falling  into  scalding  water;  men 
fell  accidentally  into  pools  of  water  at  a  temperature  of  157°  or 
158°  and  perished  in  great  suffering  from  their  skin  peeling  off. 

In  some  cases  the  effect  of  the  hot  air  on  the  men  is  said  to 
have  been  beneficial,  acting  like  a  succession  of  Turkish  baths. 
When  the  heat  on  the  Comstock  lode  first  became  intense,  the 
miners  suffered  from  pneumonia  and  rheumatism,  because  they 
went  out  at  once  into  the  cold  and  freezing  atmosphere  at  the 
top  of  the  shaft,  although  only  a  few  minutes  before  they  had 
been  in  the  heated  atmosphere  of  the  lower  levels.  Such  sudden 
changes  of  temperature  were  naturally  injurious ;  and  experience 
soon  taught  the  men  and  the  managers  that  risks  of  this  kind 
could  not  be  run  with  impunity.  Good  rooms  were  erected  at 
the  tops  of  the  shafts,  in  which  the  men  could  change  their 
clothes,  and  some  were  provided  with  baths.  These  precautions 
soon  brought  about  an  improvement  in  the  general  health  of  the 
men. 

In  ordinary  mining  operations,  men  are  rarely  subjected  to  a 
pressure  considerably  above  that  of  the  surrounding  atmosphere  ; 
but  as  work  in  compressed  air  is  occasionally  necessary,  it  is 
well  that  the  student  should  be  reminded  of  its  danger  to  health. 
Men  who  are  employed  in  making  foundations  for  bridges  or  in 
driving  tunnels,  where  compressed  air  is  used  as  a  means  of 

*  Miners"  Nystagmus,  Bristol,  1892. 

t  Lord,  "  Comstock  Mining  and  Miners."  MonograpJis  U.S.  Geol.  Survey, 
vol.  iv.,  Washington,  1883,  pp.  374  to  399. 

2  X 


690  ORE  AND  STONE-MINING. 

keeping  out  water,  suffer  at  times  from  paralysis  and  intense 
pain  in  the  back.  These  effects  of  the  confinement  seem  to  be 
mainly  felt  on  coming  out  into  a  less  dense  atmosphere,  and  may  be 
lessened  by  prolonging  the  stay  in  the  air-lock,  and  so  causing  the 
diminution  of  pressure  to  be  felt  gradually. 

5.  THRIFT. — Remarks  upon  the  condition  of  the  miner 
would  be  incomplete  without  some  mention  of  the  following 
subjects: — (i)  Provision  against  loss  of  pay  from  sickness  acci- 
dents, strikes,  and  old  age ;  (2)  Obtaining  medical  attendance  at 
a  small  cost ;  (3)  Procuring  supplies  of  food  and  clothing  upon 
the  most  reasonable  terms. 

Provident  societies  are  no  new  thing  for  the  miner ;  it  has  been 
pointed  out  by  Dr.  Wahle,  the  Director  of  the  Mining  Depart- 
ment at  Freiberg,  that  they  date  back  in  Saxony  to  the 
fifteenth  century,  and  are  as  old  as  mining  itself.  In  this 
country  at  the  present  day  three  systems  are  in  vogue  :  clubs 
for  individual  mines,  general  relief  societies  for  large  districts, 
and,  lastly,  the  ordinary  friendly  societies,  not  confined  to  miners, 
which  are  resorted  to  by  all  classes  of  workmen. 

In  Cornwall  and  Devon,  and  in  many  parts  of  Wales,  there  is 
a  club  for  each  mine,  and  the  men  agree  to  a  deduction  being 
made  from  their  wages  every  month  for  "  doctor  and  club."  At 
many  mines  the  monthly  deduction  for  the  doctor  is  either  six- 
pence, or  one  shilling,  according  as  he  attends  the  miner  only,  or 
his  family  also.*  Under  the  provisions  of  the  Stannaries  Act, 
1887,  some  of  the  old  grievances  of  the  Cornishmen  have  been 
made  to  disappear.  Each  man  has  a  right  to  choose  his  own 
doctor,  to  whom  the  amount  deducted  from  his  wages  is  paid. 
If  a  surgeon  renders  himself  unpopular  by  not  attending  to  a 
case  with  sufficient  care,  the  men  do  not  select  him  another  time, 
and  his  pay  and  reputation  suffer.  This  check  upon  the  doctors 
seems  to  be  a  sufficient  guarantee  of  the  system  working  smoothly, 
and  to  the  satisfaction  of  those  most  interested  in  the  matter — viz., 
the  men  themselves. 

The  usual  deduction  for  "  club  "  is  6d.,  and  in  a  few  cases  gd. 
per  man  per  month ;  the  usual  "  hurt  pay "  for  disablement  is 
is.  per  day.  In  the  event  of  a  fatal  accident  the  funeral  expenses 
are  borne  by  the  mine,  and  sometimes  the  sum  of  ^"10  is  given  to 
the  widow  or  dependent  relatives,  or  a  levy  of  is.  per  man  is 
made  for  their  benefit. 

The  great  faults  of  this  system  are  :  First,  the  want  of  some 
provision  for  widows,  orphans,  or  dependent  relatives  of  persons 
killed  by  accidents  ;  secondly,  the  fact  that  a  man  loses  his  "  hurt 
pay"  and  is  probably  thrown  on  the  parish  if  the  mine  in 
which  he  had  been  working  is  stopped  ;  thirdly,  the  want  of  any 

*  Foster  and  Pike,  "  Suggestions  for  the  Formation  of  a  Miners'  Per- 
manent Club  and  Relief  Society  for  Cornwall  and  Devon,"  Proc.  Min.  Inst. 
Cornwall,  vol.  i.,  p.  I. 


CONDITION  OF  THE  MINER.  691 

provision  for  ordinary  sickness.  Of  course  the  first  and  third 
objections  might  be  removed  by  increasing  the  monthly  subscrip- 
tions, but  the  second  would  still  remain — viz.,  the  uncertainty  of 
the  benefits  being  kept  up  permanently. 

Far  better  than  the  clubs  of  individual  mines  are  the  perma- 
nent relief  societies,  of  which  British  miners  have  reason  to  be 
proud.  There  are  now  nine  of  these  societies  in  different  parts 
of  England  and  Wales,  and  there  is  also  a  central  society  for 
promoting  and  watching  over  their  interests  and  extending  their 
work  to  new  districts.* 

Though  started  for  colliers,  these  societies  include  many  iron- 
stone miners  and  some  lead  miners  and  slate  quarriers  among 
their  members.  According  to  the  annual  report  of  the  Asso- 
ciation for  1891,  there  were  268,971  persons  members  of 
these  relief  societies  in  the  year  1890,  whilst  the  total  number 
employed  in  and  about  the  mines  of  the  United  Kingdom  was 
674,434,  inclusive  of  those  employed  on  private  branch  railways 
and  tramways,  and  in  washing  and  coking  coal  on  premises  adja- 
cent to  or  belonging  to  the  mine. 

The  exact  nature  of  one  of  these  societies  will  be  best  appre- 
ciated by  examining  the  rules  of  the  largest,  which  has  done, 
and  is  still  doing,  much  excellent  work  in  the  North  of  England,  t 
As  it  includes  the  Cleveland  ironstone  district,  although  this 
does  not  appear  from  the  title,  it  is  specially  adapted  for  my 
purpose.  Its  objects  are  very  clearly  defined  thus  : 

"  The  objects  of  this  Society  are  the  raising  of  funds  by  volun- 
tary subscriptions  amongst  the  members  thereof,  and  by  donations' 
from  others  to  make  provision  in  case  of  fatal  and  non-fatal 
accidents  as  follows : 

"  (a)  A  sum  at  the  death  of  a  member. 

"  (6)  A  weekly  allowance  to    the  widow  and  children   of   married 

members. 
"  (c)  A    weekly   allowance  to  members   who  suffer  from  non-fatal 

accidents. 
"  (d)  An  allowance  to  the  parent,  or  sister,  or  brother  of  a  deceased 

member  during  sickness  or  other  infirmity. 
"  (e)  Also  to  make  a  provision  for  miners  over  60  years  of  age  who  are 

permanently  unfit  to  work,  the  allowance  to  be  paid  to  be  in 

accordance  with  the  contributions  received. ' ' 

The  weekly  contribution  of  each  member  is  4d.,  and  of  a  half- 
member — i.e.,  a  boy  under  i8J  only  2d.  Three-eighths  of  these 
sums  are  devoted  to  the  superannuation  fund. 

*  Central  Association  for  Dealing  with  Distress  caused  by  Mining 
Accidents,  31  A,  King  Street,  Wigan  ;  George  L.  Campbell,  Secretary. 

+  Eules  of  the  Northumberland  and  Durham  Miners'  Permanent  Belief 
Fund  Friendly  Society.  Established  June  7,  1862.  Chief  Office— 
5,  Queen's  Square,  Newcastle-upon-Tyne.  1892. 

J  A  boy  under  18  but  over  16  may  be  a  whole  member  if  he  likes  ;  a 
boy  under  16  can  only  be  a  half  member. 


692  OKE  AND  STONE  MINING. 

The  benefits  are  in  the  case  of 

1.  Non-fatal  accidents. 

2.  Fatal  accidents. 

3.  Old  age. 

If  a  member  is  disabled  by  an  accident  for  more  than  a  weeky 
but  not  less,  he  receives  the  sum  of  55.  a  week  or  lod.  per  work- 
ing day,  and  a  half-member  2s.  6d.  per  week  or  $d.  per  day.  The 
payments  go  on  in  this  way  for  twenty-six  weeks,  when,  if  the 
person  is  still  disabled,  he  becomes  entitled  to  the  higher  relief 
of  8s.  per  week,  or  45.  if  he  is  a  half -member,  so  long  as  he  is 
unable  to  work  from  the  effects  of  the  accident. 

In  the  case  of  a  death  by  accident,  the  widow  of  a  married 
member  receives  a  legacy  of  ^£5,  the  relatives  of  an  unmarried 
member  receive  ^23,  and  those  of  a  half -member  £12.  The 
widow  also  draws  5$.  a  week  from  the  funds  for  the  rest  of  her 
life,  so  long  as  she  remains  unmarried,  and  2s.  a  week  for  each 
child,  until  the  boys  are  thirteen  and  the  girls  fourteen  years  of 
age. 

Aged  and  infirm  members  over  sixty  years  of  age  who  are 
certified  medically  to  be  unfit  to  follow  their  employment  receive 
45.  per  week  ;  but  the  amount  of  the  pension  may  be  reduced  if 
the  funds  at  any  time  are  insufficient  to  keep  up  the  present 
allowance. 

During  the  year  1891  this  Society  had  113,124  members;  the 
contributions  of  the  members  amounted  to  ^90,169,  those  of  the 
owners  of  collieries  to  ^4860,  in  addition  to  which  there  was  an 
income  of  ^5208  from  invested  funds.  The  following  claims 
were  made  upon  the  Society : 

Minor  Accidents. — 16,500  claims  for  relief  were  made;  the 
average  length  of  the  period  of  disablement  was  about  3^-  weeks 
each. 

Permanent  Disablement. — 195  claims  for  accidents  that  have 
caused  disablement  lasting  more  than  26  weeks;  the  average 
duration  of  each  is  estimated  to  be  3^  years. 

Fatal  Accidents. — 93  widows  came  on  to  the  funds. 

Children. — 185  children  came  on  to  the  funds. 

Old  Age. — 442  new  claims  for  superannuation  were  made. 

According  to  the  report  of  the  Central  Association  *  the  nine 
societies  gave  relief  for  754  deaths  by  accidents,  and  for  39,411 
cases  of  disablement  during  the  year  1890. 

We  learn  from  the  Reports  of  Inspectors  of  Mines  that  there 
were  1206  deaths  from  accidents  at  all  the  mines  of  the  United 
Kingdom  in  that  year,  consequently  it  is  evident  that  a  large  pro- 
portion of  the  victims  of  these  fatalities  were  insured,  and  that 

*  Central  Association  for  Dealing  with  Distress  Caused  by  Mining  Acci- 
dents. Report  of  the  Proceedings  at  the  Twelfth  Annual  Conference,  London, 
1891,  Tables  VI.  and  VII.,  pp.  36-7. 


CONDITION  OF  THE  MINER.  693 

their   families   or   dependent    relatives   received   some   form   of 
relief. 

Altogether  there  were  2 39 5  widows  and  3496  children  receiving 
benefits  from  the  funds  of  the  nine  societies  in  the  year  1890. 

The  percentage  proportion  of  the  contributions  of  the  colliery 
•owners  to  those  of  the  ordinary  members  is  less  in  the  Northumber- 
land and  Durham  Society  than  in  the  others.  In  1890  it  repre- 
sented only  5- 7  per  cent.,*  whilst  in  the  Lancashire  and  Cheshire 
Society  it  was  24*1  per  cent.,  in  the  North  Wales  Society  25*2  per 
•cent.,  and  in  the  Monmouthshire  and  South  Wales  Society  24  per 
•cent.  If  we  turn  to  Table  IX.  of  the  report,  the  reason  of  this 
difference  becomes  apparent ;  it  will  be  seen  that  all,  or  a  very 
large  number,  of  the  members  of  these  three  societies  have 
entered  into  an  agreement  with  the  owners  not  to  bring  any 
claim  against  them  under  the  Employers'  Liability  Act  of  1880, 
or,  to  use  the  common  expression,  they  have  "  contracted  them- 
selves out  of  the  Act."  They  consider  that  the  employer's  con- 
tribution is  worth  more  to  them  than  the  chance  of  occasionally 
obtaining  compensation  by  proving  negligence  against  him  in  a 
court  of  law. 

Enough  has  been  said  to  show  the  present  state  of  the  volun- 
tary system  of  relief  as  it  now  exists  in  England  and  Wales ; 
much  of  the  distress  caused  by  mining  accidents  is  relieved  by  the 
nine  principal  societies,  and,  in  addition,  there  are  numerous 
smaller  societies  established  for  individual  mines,  having  in  the 
main  the  same  objects  as  the  larger  ones. 

Something  more  is  needed — viz.,  relief  in  sickness,  and  old 
.age  pensions  for  all.  Some  of  the  existing  clubs  of  individual 
mines  give  sick  pay  to  their  members,  and  there  are  the  ordinary 
Friendly  Societies  established  on  a  far  firmer  basis,  which  can  be 
resorted  to  by  the  miner  like  any  other  workman.  As  far  there- 
fore as  sickness  is  concerned  there  is  machinery  available  by 
which  the  miner  in  any  part  of  the  kingdom  can  make  the  neces- 
,sary  provision  for  himself  and  his  family. 

If  he  requires  a  pension,  he  can  get  one  upon  the  very  best 
security  by  going  to  the  nearest  Post  Office.  A  young  man  of 
twenty  can  obtain  a  deferred  annuity  of  55.  a  week,  commencing 
.at  the  age  of  sixty,  by  paying  £2  35.  ^d.  a  year,  or  lod.  a  week. 
If  the  person  wishes  to  discontinue  his  insurance,  he  can  do  so, 
and  all  the  money  he  has  paid  will  be  returned  to  him,  provided 
that  an  instalment  of  the  annuity  has  not  become  due.  However, 
as  the  facilities  afforded  by  the  Post  Office  have  not  been  utilised 
to  any  great  extent,  compared  with  the  numbers  of  the  working 
classes,  and  as  a  large  number  of  persons  spend  the  last  years  of 
their  lives  and  end  their  days  as  paupers  in  the  workhouse,  it  is 
thought  by  most  people  that  something  more  should  be  done.  Great 

*  Op.  tit.  Tables  IV.  and  V.,  pp.  34-5. 


694  ORE  AND  STONE-MINING. 

difference  of  opinion  exists  upon  the  subject;  much  has  been 
written,  and  still  more  said  during  the  last  few  years,  and  the 
controversy  has  raged  mainly  upon  the  question  of  State  aid. 
The  proposals  may  be  summed  *  up  as  involving  one  of  the  three 
following  principles : 

1.  State  endowment. 

2.  State  assistance. 

3.  State  compulsion. 

1.  The  first,  that  of  Mr.  Charles  Booth,  means  the  free  gift  by 
the  State  of  a  pension  of  55.  a  week  to  every  citizen  on  attaining 
the  age  of  sixty-five  years. 

2.  The  best  known  scheme  coming  under  the  second  head  is 
that  proposed  by  a  Parliamentary  Committee,t  presided  over  by 
Mr.  Joseph  Chamberlain,  M.P.    Its  main  features  are  as  follows : 
If  a  young  man  pays  ^5  to  the  Post  Office  Savings  Bank  before 
the  age  of  twenty-five,  he  is  to  be  at  once  credited  with  ^15 
more  from  a  State  pension  fund ;  he  will  then  have  to  pay  £i  a 
year  to  the  Post  Office  for  forty  years,  and  at  sixty-five  he  will 
become  entitled  to  a  pension  of  55.  a  week.     If  he  dies  before  the 
age  of  sixty-five,  there  are  arrangements  for  granting  a  pension 
to  his  widow  and  children.     It  is  also  proposed  that  a  male  shall 
be  able  to  purchase  a  pension  of  55.  a  week  on  payment  of  one- 
half  of  the  sums  just  mentioned ;  but  in  this  case  there  is  no 
provision  for  a  family. 

3.  The  last  plan  of  providing  old  age  pensions  is  that  which 
has  been  advocated  for  so  many  years  and  with  so  much  skill  by 
the  Rev.  Canon   Blackley.     He  would  compel  every  one  to  de- 
posit with  the  State,  before  the  age  of  twenty-one,  a  sum  of  about 
;£io,  which  would  suffice  to  provide  him  with  a  pension  of  55. 
a  week  on  attaining  his  sixty-fifth  year.     Canon  Blackley  points 
out  that  in  his  youth,  before  marriage,  a  man  would  be  able  to 
make    the   proposed  saving,  and   that  after  this   he  would   no 
longer  be  troubled  by  the  thought  of  not  being  able  to  keep  up 
his  payments. 

Many  arguments  may  be  adduced  in  favour  of  each  of  the 
three  principles  of  old  age  pensions,  but  opinions  concerning 
them  must  largely  depend  upon  the  "  personal  equation  "  of  the 
individual — that  is  to  say,  upon  his  general  views  regarding  the 
interference  of  the  State  in  such  matters. 

The  Gordian  knot  of  this  difficult  question  has  been  cut  in 
Germany  by  the  Law  of  Insurance  against  Old  Age  and  Infirmity  J 
passed  in  1889.  Under  this  law  the  means  for  providing  the 
allowances  to  infirm  and  aged  persons  are  made  up  of  contribu- 

*  Reports  of  the  Chief  Registrar  of  Friendly  Societies  for  the  Year  1891, 
London,  1892,  p.  26. 
f  The  Times,  London,  May  21,  1892. 
J  Translated  in  Parliamentary  Paper  (C. — 5827),  1889,  price  ^d. 


CONDITION  OF  THE  MINER.  695 

tions  from  the  State,  the  employers  and  the  persons  insured,  the 
two  latter  paying  like  amounts. 

The  method  of  insurance  may  be  briefly  described  as  that  of 
State  compulsion  with  State  aid,  together  with  obligatory  contri- 
butions from  the  employer.  This  bold  experiment  will  be  watched 
with  interest. 

This  subject  of  thrift  must  not  be  concluded  without  a  few 
words  about  one  requisite  for  the  treatment  of  diseases — viz., 
hospitals.  In  this  country  the  provision  of  such  institutions  is 
frequently  left  to  private  benevolence;  in  the  great  tin  mining 
centre  of  Redruth,  for  instance,  the  burden  of  ensuring  accom- 
modation for  the  sick  and  injured  has  been  taken  by  a  charitable 
owner  of  mineral  property.  According  to  the  balance  sheets 
of  the  institution  from  1885  to  1892,  he  has  paid  on  an  average 
more  than  40  per  cent,  of  the  total  cost,  which  exceeds  ^1300 
yearly ;  the  remainder  is  met  by  contributions  from  private  per- 
sons, companies  working  mines  in  the  neighbourhood  and  their 
workmen. 

The  Oakeley  Hospital  at  Blaenau  Festiniog,  which  ministers  to 
the  ills  of  some  of  the  quarry  men,  was  built  by  the  landowner, 
and  is  now  supported  by  the  largest  slate  mine. 

Many  of  the  large  Continental  mines  keep  up  establishments  of 
this  kind,  and  throw  them  open  gratis  to  their  employes.  The 
same  plan  is  adopted  by  some  of  the  large  British  companies 
working  mines  abroad,  and  even  at  Boryslaw,  where  much  of  the 
mining  is  being  carried  on  in  the  most  primitive  manner,  a  Gali- 
cian  company  supports  a  small  hospital,  and  admits  not  only  its 
own  servants,  but  also  any  urgent  cases  requiring  surgical  or 
medical  attendance. 

Fortunately,  it  often  happens  that  a  mine  has  not  accidents 
enough  to  require  the  constant  use  of  a  hospital  and  the  entire 
services  of  a  surgeon.  This  is  the  case,  for  instance,  at  some  large 
mines  near  Ems  ;  the  company  has  built  a  hospital  and  keeps  it  in 
readiness,  in  case  of  accidents  or  sickness,  with  a  doctor  on  the 
premises  ;  but,  in  consideration  of  his  small  stipend,  he  is  allowed 
to  have  three  rooms  at  his  disposal  in  which  he  can  treat  private 
patients.  In  the  United  States  sick  and  injured  miners  sometimes 
go  to  private  hospitals,  which  are  managed  by  medical  men. 

Before  complete  recovery  from  an  illness  or  the  effects  of  an 
accident,  a  man  passes  through  a  period  of  convalescence,  during 
which  he  requires  little  medical  aid,  but  depends  for  his  final 
restoration  to  health  mainly  upon  good  food,  quiet  and  regular 
living,  and  plenty  of  fresh  air.  It  is  a  question  in  some  mining 
districts  whether  it  is  better  to  support  a  convalescent  home  in  the 
locality  itself,  or  to  subscribe  to  one  at  a  distance.  The  latter 
plan  is  in  many  cases  cheaper,  owing  to  the  smaller  cost 
for  general  expenses ;  and  at  the  same  time  it  is  better  for  the 
patient,  wLo  profits  by  the  change  of  air  and  scene,  which  in 


696  ORE  AND  STONE-MINING. 

themselves  are  powerful  remedial  agents.  In  a  small  island  like 
ours,  it  is  not  difficult  as  a  rule  for  the  patient  to  get  to  the 
sea  coast  without  a  ruinous  expenditure  of  money  in  railway 
fares.  At  some  of  the  sea-side  convalescent  homes  a  miner  may 
be  boarded  and  lodged  for  three  weeks  at  a  total  cost  of  £1.  i6s. ; 
therefore  if  a  mine  is  employing  500  men,  and  each  man  sub- 
scribes ^d.  per  month  of  four  weeks,  more  than  ^£13  can  be  raised 
annually,  or  sufficient  to  give  seven  invalids  a  stay  of  three  weeks 
each  at  the  sea. 

In  writing  upon  the  question  of  thrift,  mention  must  be  made  of 
co-operative  societies,  which  give  the  workman  the  opportunity  of 
buying  his  food  and  clothing  at  the  most  reasonable  rates.  They 
are  so  well  known  nowadays  that  no  description  of  their  advantages 
is  required ;  but  it  is  well  to  point  out  that  their  success  does  not 
necessarily  depend  upon  their  having  a  very  large  number  of 
customers,  such  as  could  only  be  expected  in  a  very  populous 
district.  Two  instances  of  co-operative  societies  in  the  Isle  of 
Man  prove  this  fact,  and  show  that  such  an  institution  may 
prosper  commercially,  and  do  good  and  useful  work  in  a  mere 
village  depending  upon  a  mine  employing  only  200  or  300 
persons  underground. 

6.  RECREATION. — I  am  well  aware  that  many  will  say 
that  in  the  matter  of  recreation  the  mine  manager  had  better 
not  interfere  at  all ;  I  do  not  take  this  view.  Men  and  boys 
require  diversions  of  some  kind  in  order  to  refresh  their  bodies 
after  toil,  and  the  manager  of  a  large  mine  often  has  the  oppor- 
tunity of  directing  their  amusements  into  the  best  channels. 
Tastes  differ:  some  men  will  find  relaxation  in  reading,  and 
will  be  glad  to  be  able  to  borrow  books  from  a  library ;  others 
are  musical,  and  will  prefer  to  join  a  band  ;  boys,  in  spite,  of  hard 
bodily  work  at  the  mine,  will  delight  in  active  games  as  soon  as 
they  are  free.  As  an  example  of  what  may  be  done  I  will  cite  the 
names  of  the  clubs  established  at  the  collieries  of  the  Douchy  Com- 
pany in  the  north  of  France  as  recreative  institutions  :  Archers, 
crossbowmen,  gymnasts,  philharmonic,  and  pigeon  fanciers.  It 
will  be  seen  from  this  list  that  a  great  many  different  tastes 
have  been  studied  in  order  to  encourage  the  men  to  employ  their 
spare  time  in  a  wholesome  manner  instead  of  going  to  pot-houses, 
to  the  injury  of  their  purses,  if  not  to  the  detriment  of  their 
health. 

An  example  on  this  side  of  the  Channel  may  be  taken  from 
the  extensive  collieries  in  Derbyshire  and  Nottinghamshire, 
owned  by  Colonel  Seely,  M.P.,  who  has  established  workmen's 
clubs,  cricket  club,  football  club,  pig  club,  a  band,  and  an  annual 
Hower  show  for  the  benefit  of  his  men.  The  cricket  ground  is 
one  of  the  best  in  Derbyshire,  and  the  club-house  is  a  large  build- 
ing containing  three  billiard-tables,  reading  and  smoking  rooms, 
and  a  lending  library ;  the  members  can  obtain  any  sort  of 


CONDITION  OF  THE  MINER.  697 

refreshment  they  like  at  reasonable  prices.  The  band  plays 
three  times  a  week  in  the  club  grounds.  In  addition,  each  sepa- 
rate colliery  has  its  club  with  a  billiard-table,  and  other  appli- 
ances for  recreation.  All  these  institutions  are  under  the  control 
of  committees  of  the  workmen,  presided  over  by  the  General 
JManager. 


698 


CHAPTER  XVII. 
ACCIDENTS. 

Death-rate  of  miners  from  accidents — Relative  accident  mortality  under 
ground  and  above  ground — Fatalities  :  underground,  from  falls  of 
roof,  from  accidents  in  shafts,  from  blasting  accidents,  from  under- 
ground fires,  from  irruptions  of  water  and  sundry  other  causes — 
Accidents  above  ground — Boiler  explosions — Non-fatal  accidents — • 
Ambulance  training. 

FEW  persons  will  deny  the  dangers  of  the  miner's  calling ;  some,  how- 
ever, consider  that  the  public  form  an  exaggerated  idea  of  these 
perils  from  dwelling  too  much  upon  occasional  colliery  explosions. 

Death-rate  of  Miners  from  Accidents. — In  the  first  place 
comes  the  question  :  What  is  a  dangerous  trade  ?  If  we  look  at 
the  vital  statistics  quoted  from  Dr.  Ogle  in  the  last  chapter,  it 
appears  that  the  majority  of  miners,  thanks,  partly,  to  their 
starting  originally  with  a  more  than  average  good  constitution, 
lead  a  longer  life  than  many  tradesmen  in  towns.  In  spite  of 
the  diseases  and  accidents  to  which  he  is  liable,  the  average  miner 
is  better  off  than  most  people  would  have  supposed,  before  they 
became  acquainted  with  the  figures.  On  the  other  hand,  if  wre 
limit  our  attention  to  accidents,  we  find  that  the  miner-  gets  far 
more  than  his  share. 

It  may  be  asserted  without  fear  of  contradiction  that  a  calling 
with  an  annual  mortality  of  i  per  1000  from  accidents,  is 
hazardous.  The  statistics  concerning  accidents  in  this  country 
are  given  annually  in  the  statistical  summaries  prepared  by  Her 
Majesty's  Inspectors  of  Mines;  and  it  will  be  seen  from  the 
published  figures  that,  taking  all  the  mines  in  the  United 
Kingdom  and  including  casualties  above  and  below  ground, 
there  was  an  average  annual  mortality  from  accidents  of  2-18  per 
1000  persons  employed  during  the  ten  years  1873  *°  x^^2  inclu- 
sive, and  that  in  the  next  decade  the  mortality  dropped  to  178 
per  1000. 

In  this  country  an  accident  is  classed  as  fatal  if  it  causes 
the  death  of  the  injured  person  within  a  year  and  a  day  of 
the  date  of  the  occurrence ;  it  is  therefore  possible  that  in 
certain  very  rare  cases,  when  more  than  a  year  elapses  before  a 
man  succumbs  to  his  hurts,  an  accident  may  be  registered  as 
non-fatal,  although  it  finally  turns  out  to  be  fatal.  Cases  of 


ACCIDENTS. 


699 


this  kind  are  so  few  that  the  correctness  of  the  British  statistics 
cannot  be  appreciably  affected  by  them. 

In  an  interesting  report  upon  the  Exhibition  held  in  Berlin  in 
1889  of  appliances  for  the  prevention  of  accidents,  M.  Paul 
Habets  gives  a  careful  summary  of  the  progress  realised  in 
Belgium,  France,  Great  Britain,  and  Prussia.*  He  divides  his 
results  into  periods  of  ten  years : 

TABLE  I. 
Annual  Death-rate  from  Accidents  per  1000  Persons  Employed, 


Period. 

Belgium. 

France. 

Great  Britain. 

Prussia. 

1851  to  i860 
1861  to  1870 
1871  to  1880 
1880  to  1888 

2'97 
260 

2'45 
2-13 

3-40* 
2-96 
2'2I 

i'57 

4-07 
3-32 
2'35 
1-94 

4'9lt 

6-33 
4-90 
2-96 

1853  to  1860. 


t  1852  to  1860. 


These  figures  show  a  steady  diminution  in  the  number  of 
accidents  excepting  in  Germany,  for  in  the  decade  1861  to  1870 
the  mortality  was  terrible ;  but  even  the  most  favourable  averages 
are  far  above  the  standard  of  i  per  TOOO,  which  has  been  assumed 
as  the  mortality  ratio  of  a  dangerous  occupation. 

Relative  Accident  Mortality  amongst  Underground  and 
Above-ground  Workers. — Descending  into  details,  let  us 
examine  how  the  two  classes  of  mines — viz.,  those  under  the  Coal 
and  those  under  the  Metalliferous  Act — compare  with  one  another. 
The  figures  will  be  made  most  plain  by  putting  them  in  a  tabular 
form. 

TABLE  II. 


Decennial 
Period. 

Average  Number  of 
Persons  Employed 
Underground 
and  Above-ground 
Annually. 

Total  Number  of 
Lives  lost  by 
Accidents  in  the 
D  eennial 
Period. 

Average  Annual  Death- 
rate  from  Accidents 
per  1000  Persons 
Employed. 

Mine 

1873  to  l882 
1883  to  1892 

3  classed  under  the  ( 
503,428 
571,719 

3oal  Mines  Regula 

11,294 
10,327 

tion  Act. 

2-243 
I  -806 

Mines  cla 

1873  to  1882 
1883  to  1892 

ssed  under  the  Mete 

55,388 
42,481 

illiferous  Mines  R< 

909 
612 

'gulation  Act. 

1-641 
1-440 

According  to  these  figures,  work  at  mines  under  the  Coal  Mines 

*  "Les  Accidents  dans  les  Mines  et  1'Exposition  Generate  Allemande 
pour  la  Protection  centre  les  Accidents  (Berlin,  1889)."  Revue  Universellc. 
des  Mines,  3°  strie,  t.  ix.  et  xi.,  34°  annee,  1890. 


700 


ORE  AND  STONE-MINING. 


Act  presents  decidedly  more  perils  than  work  at  mines  under  the 
Metalliferous  Act.  Speaking  roughly,  the  relative  degrees  of 
danger  were  as  i  i]to  8  in  the  first  period  and  9  to  7  in  the  second. 
In  order  to  make  the  comparison  of  any  real  value,  it  is  neces- 
sary to  go  somewhat  further.  Owing  to  the  amount  of  labour 
required  for  "  dressing,"  the  proportion  of  surface  hands  is  much 
larger  at  a  tin,  copper,  lead,  or  slate  mine,  than  at  a  colliery.  In 
round  numbers  about  one-fifth  of  the  persons  employed  at  mines 
under  the  Coal  Mines  Regulation  Act  work  above  ground,  and  four- 
fifths  underground  ;  at  mines  under  the  Metalliferous  Mines  Act 
the  proportions  are  two-fifths  above  ground,  and  three-fifths  under- 
ground. Consequently,  as  the  proportion  of  the  surface  hands 
with  a  small  risk  is  twice  as  great  in  one  case  as  in  the  other,  it  is 
impossible  properly  to  compare  the  risks  of  the  underground 
workers  until  this  source  of  error  has  been  eliminated.  The 
death-rates  calculated  separately  are  as  follows  : 

TABLE  III. 

Average  Annual  Death-rate  from  Accidents  per  1000  Persons 
employed  in  and  about  the  Mines  of  the  United  Kingdom  of 
Great  Britain  and  Ireland. 


Decennial  Period. 

Below  Ground. 

Above  Ground. 

Coal  Mines 
Act. 

Metalliferous 
Mines  Act. 

Coal  Mines 
Act. 

Metalliferous 
Mines  Act. 

1873  to  1882        . 
1883  to  1892        . 

2-572 
2  'OO9 

2-348 
2-145 

0-919 
Q'959 

0-578 
0-392 

In  the  first  period  the  relative  amounts  of  danger  to  under- 
ground workers  were  as  51  to  47,  a  very  different  proportion 
from  1 1  to  8  as  appeared  from  the  other  table ;  in  the  second 
period  the  mines  under  the  Coal  Mines  Act  have  the  advantage, 
whereas  by  the  original  table  "they  seem  to  be  more  dangerous 
than  those  under  the  Metalliferous  Act. 

The  necessity  for  considering  the  underground  death-rate 
separately,  when  inquiring  into  the  relative  amounts  of  danger  at 
different  classes  of  mines  is  well  illustrated  in  the  case  of  the 
underground  slate  quarries  of  North  Wales.  These  appear  to  be 
less  dangerous  than  collieries,  or  more  dangerous  according  as 
the  surface  hands  are  included  or  not  in  the  calculations.  Taking 
the  ten  years  1875  to  1884,  the  annual  death-rate  from  accidents 
at  the  underground  slate  quarries  was  2*07  per  1000  among  all 
the  workers  as  a  whole,  and  3-2  per  1000  among  the  under- 
ground workers  taken  separately.  The  former  rate  is  better  than 
the  corresponding  2-243  (Table  II.)  of  mines  under  the  Coal  Mines 


ACCIDENTS.  70I 

Act,  and  the  latter  is  worse  than  2^572  (Table  III.).  Conse- 
quently the  average  underground  slate-quarrier  has  a  more 
perilous  calling  than  the  average  collier. 

While  correcting  one  misapprehension  I  must  guard  against 
another,  and  point  out  that  the  Coal  Mines  Kegulation  Act  applies 
to  mines  of  coal,  stratified  ironstone,  shale,  and  fireclay.  Therefore 
the  figures  given  do  not  refer  solely  to  coal-mines,  and  do  not  re- 
present precisely  the  risks  of  the  collier,  and  it  becomes  necessary 
to  examine  whether  the  introduction  of  certain  disturbing 
elements  affects  the  average  risk  to  any  great  extent  or  not. 
Compared  with  coal,  the  amounts  of  fireclay,  ironstone,  and 
shale  are  small,  and  the  total  quantity  of  these  minerals  raised 
in  1893  was  less  than  6  per  cent,  of  the  weight  of  the  coal ;  any 
error  caused  by  the  introduction  of  ironstone  and  other  mines,  is 
likely  therefore  to  be  inconsiderable.  After  coal,  the  most 
important  mineral  wrought  under  the  Coal  Mines  Act  is  ironstone, 
and  more  than  half  the  total  quantity  raised  is  obtained  in  the 
Cleveland  district.  From  the  figures  given  in  the  reports  of  the 
inspectors  of  mines,  I  find  that  from  1873  to  1882  there  were  183. 
deaths  from  accidents  underground  in  the  Cleveland  district, 
with  an  average  annual  underground  staff  of  6863  persons,  con- 
sequently the  average  death-rate  was  2'66  per  1000;  in  the 
following  decennial  period  it  was  2-21  per  1000.*  Both  these 
proportions  are  higher  than  the  corresponding  ratios  calculated 
for  the  whole  of  the  mines  under  the  Coal  Mines  Act ;  therefore 
if  all  disturbing  factors  were  eliminated,  we  may  fairly  assume 
that  the  average  underground  death-rate  at  the  coal-mines  proper 
did  not  exceed  the  figures  given  in  Table  III. 

On  the  other  hand,  I  must  remark  that  the  Metalliferous  Mines- 
Regulation  Act  applies  to  all  mines  not  included  under  the  Coal 
Mines  Act,  and  the  statistics  under  the  former  Act  refer  not  only 
to  mines  worked  for  ores,  but  also  to  salt-mines  and  underground 
slate  and  stone  quarries.  The  figures  quoted  cannot  be  taken  as- 
relating  solely  to  true  metalliferous  mines. 

For  the  sake  of  comparison  I  have  extracted  from  the  annual 
reports  of  the  inspectors  of  mines,  the  figures  for  the  metalliferous 
mining  district  of  Cornwall  and  Devon,  including  also  a  few 
mines  in  Somersetshire  and  Dorsetshire.  During  the  ten 
years  1873  to  1882  there  were  280  deaths  from  accidents  under- 
ground, with  an  average  underground  staff  of  10,629  persons. 
This  means  an  average  annual  death-rate  among  the  underground 
workers  of  2-63  per  1000.  The  corresponding  figure  for  the  ten 
years  1883  to  1892  was  found  to  have  been  2-54  per  1000. 

The  conclusions  arrived  at  from  these  statistics  are,  first,  that 

*  From  1873  to  1883  the  published  statistics  refer  to  the  whole  of  the 
North  Biding  of  Yorkshire,  where  a  little  coal  is  worked,  but  not  in  suffi- 
cient quantity  to  affect  the  ratios  perceptibly  ;  since  1883  the  Cleveland 
figures  have  been  kept  entirely  separate. 


702  ORE  AND  STONE-MINING. 

the  mines  under  the  Coal  Mines  Regulation  Act  are  not  always 
more  destructive  of  life  than  the  mines  under  the  Metalliferous 
Mines  Regulation  Act ;  and  secondly,  that  certain  mines  worked  for 
metallic  ores,  such  as  the  iron  mines  of  Yorkshire,  and  the  tin  and 
copper  mines  of  Cornwall  and  Devon,  present  more  dangers  to  the 
underground  worker  than  an  average  colliery,  in  spite  of  the 
almost  complete  absence  of  explosions  of  gas.  In  other  words,  as 
has  been  pointed  out  repeatedly,  fire-damp  is  not  the  worst  enemy 
the  miner  has  to  contend  with.  It  is  very  evident  also  that  if 
different  classes  of  mines  are  to  be  compared  as  regards  dangers, 
the  figures  must  be  restricted  to  those  working  below  ground ;  and  it 
is  to  be  regretted  that  some  of  the  official  reports  concerning  mines 
in  other  countries  afford  no  means  of  making  the  proper  compa- 
rison. On  the  other  hand,  foreigners  sometimes  complain  that  our 
British  statistics  do  not  give  them  the  true  coal-mining  accidents 
separately ;  but  when  the  two  minerals,  coal  and  ironstone,  are 
being  worked  in  the  same  pit,  and  when  the  preliminary  and 
exploratory  work  is  common  to  both  minerals,  it  is  impossible  to 
draw  any  strict  line  of  division. 

Classification  of  Accidents. — In  order  to  obtain  some  general 
ideas  concerning  the  kinds  of  accidents  which  occur  at  mines  we 
must  begin  by  classifying  them.  The  basis  of  such  a  classification 
may  be  either  the  place  where  the  accident  happened,  or  the 
cause  of  the  occurrence.  Usually  the  classification  is  founded 
upon  both. 

Following  the  plan  which  was  adopted  in  the  early  days  of 
mine  inspection  in  this  country,  the  British  classification  begins 
by  separating  the  accidents  which  happened  underground  from 
those  which  took  place  at  the  surface,  and  then  the  underground 
accidents  are  arranged  under  the  four  main  heads  : 

Explosions  of  fire-damp  or  coal-dust. 
Falls  of  ground. 
In  shafts. 
Miscellaneous. 

The  classification  is  not  strictly  logical,  because  it  to  a  certain 
extent  mixes  up  cause  and  place ;  there  may  be  explosions  of  fire- 
damp or  falls  of  ground  in  shafts,  but  these  would  naturally  be 
placed  under  the  headings  which  most  particularly  describe  them, 
so  that  the  heading  "  in  shafts  "  does  not  always  include  every 
accident  which  has  happened  there.  However,  the  classification 
has  been  used  so  long,  and  is  so  well  understood,  that  it  would  be 
absurd  to  make  any  great  alteration  now. 

The  relative  importance  of  each  of  these  classes  is  brought  out 
by  the  following  table,  which  has  been  calculated  for  the  same 
periods  as  the  preceding  one  : 


ACCIDENTS. 
TABLE  IV. 


703 


Kinrl  nf  Annidpnt 

All  the 
Mines  in  the 
United  King- 
dom  under 
the  Coal 
Mines  Regu- 
lation Act. 

All  the 
Mines  in  the 
United  King- 
dom under 
the  Metal- 
liferous Mines 
Regulation 
Act. 

Stratified 
Ironstone 
Mines  of  the 
Cleveland 
District. 

Tin,  Copper, 
&c.,  Mines  of 
Cornwall, 
Devon,  Dor- 
set,  and 
part  of 
Somerset. 

§3      » 

* 

!  % 

* 

(-1             • 

"o 

f-i 

O            GO 

% 

||| 

-5  o 

111 

|1 

111 

|| 

1|| 

<v  —' 

3^1 

0   OJ 

f  — 

g£l 

IS 

3  £3 

11 

«£•« 

gjj 

H      -° 

Pi 

H     * 

1 

H      * 

EH      £ 

5 

TEN  YEARS—  1873  TO  J882  INCLUSIVE. 

/Explosions       of 
£  "g        fire-damp 

2629 

23-3 

4 

2'0 

%s]  Falls  of  ground 

4534 

40'  I 

313 

34'4 

92 

447 

85 

25-5 

W  8  1  In  shafts   . 

1303 

ITS 

241 

26-s 

12 

5'8 

107     32-0 

(  Miscellaneous    . 

1907 

I7-0 

227 

25-0 

75 

36-4 

88 

26-3 

Above  ground   . 

921 

8-1 

128 

14-1 

23 

ii'i 

54 

I6'2 

Totals   . 

11294 

IOO 

909 

IOO 

206 

IOO 

334 

ICO 

TEN  YEARS—  1883  TO  1892  INCLUSIVE. 

/•Explosions       of 

£  ^  |      fire-damp 

1469 

14-2 

6 

I'D 

— 

— 

— 

— 

^  is  -j  Falls  of  ground 
pq  2     In  shafts   . 
v  Miscellaneous    . 

4602 
878 
2316 

44-6 

8'5 
22-4 

238 
132 
169 

21-6 
27-6 

83 

2 
32 

24-4 

45 

£ 

21-8 

36-9 
29-6 

Above  ground   . 

1062 

10-3 

67 

10-9 

14 

107 

24 

117 

Totals   . 

10327 

TOO 

612 

IOO 

W 

IOO 

206 

IOO 

The  further  subdivision  adopted  in  this  country  for  classifying 
is  given  in  the  table  below  : 


7  04 


ORE  AND  STONE-MINING. 


TABLE  V. 

Classification  of  Accidents. 


UNDERGKOUNDx 


FALLS  OF  GEOUND. 


IN  SHAFTS 


MISCELLANEOUS.    •< 


ON  SURFACE 


^EXPLOSIONS  OF  FIRE-DAMP  OR  COAL-DUST. 
(Falls  of  roof. 
1     „     ,,  side. 

Overwinding. 

Ropes  and  chains  breaking. 

Whilst  ascending  or  descending  by 
machinery. 

Falling  into  shafts  from  surface. 

Things  falling  from  surface. 

Falling  from  part  way  down. 

Things  falling  from  part  way  down. 

Miscellaneous  in  shafts. 

Explosions  of  gunpowder,  &c. 

Suffocation  by  gases. 

Irruptions  of  water. 

Falling  into  water. 

On  inclined  planes. 

By  trams  and  tubs. 

By  machinery  underground. 

Sundries  underground. 
(  By  machinery  on  surface. 
J  Boilers  bursting. 
1  On  railways  and  tramways. 
{  Miscellaneous  on  surface. 

Explosions  of  Fire-Damp  or  Coal-Dust. — With  few  excep- 
tions, fatalities  from  explosions  of  fire -damp  in  this  country  are 
confined  to  coal  mines. 

Falls  of  Ground. — Table  IV.  indicates  plainly  what  point 
requires  the  special  attention  of  the  mine-owner,  in  his  endeavours 
to  ward  oft*  the  dangers  which  threaten  his  workmen.  By  far  the 
largest  proportion  of  fatalities  occur  from  falls  of  ground ;  and  the 
same  story  is  told  by  the  statistics  of  other  countries.  Without 
attempting  to  refer  to  all  the  information  which  is  published  on 
the  subject,  it  will  suffice  to  say  that  36  per  cent,  of  the  deaths  at 
Prussian*  coal  mines  in  1891,  and  47  per  cent,  of  those  at  the  ore 
mines,  are  ascribed  to  this  cause.  This  cannot  be  a  matter  of 
surprise  when  we  consider  the  conditions  under  which  the  miner 
carries  on  his  labour :  in  the  overhand  stopes  of  an  ore  mine,  he  is 
constantly  taking  down  the  roof  above  his  head ;  in  working  away  a 
stratified  deposit,  he  is  continually  pushing  forward  under  a  fresh 
part  of  the  overlying  stratum,  which  may  have  concealed  and  un- 
suspected joints  ;  at  other  times,  he  is  engaged  in  removing  from 
the  parent  bed  huge  masses  of  rock  weighing  many  tons  each ; 
no  wonder,  therefore,  that  he  is  occasionally  caught  by  a  fall. 

These  accidents  are  best  guarded  against  by  incessant  watchful- 
ness on  the  part  of  the  men  and  masters,  by  putting  in  supports, 
even  when  they  do  not  appear  immediately  necessary,  and  by 

*  Zeitschr.f.  B.-H.-u.  S.-Wesen,  vol.  xl.,  1892,  p.  32. 


ACCIDENTS.  705 

regulations  defining  how  closely  props  shall  be  set.  Testing  the 
ground  by  "  sounding" — i.e.,  by  striking  it  with  the  hammer  and 
noticing  the  sound  emitted — often  enables  the  workman  to  detect 
whether  the  rock  is  firm  or  not ;  but  the  indication  is  not  always 
reliable.  If  the  mass  of  rock  is  large,  it  may  "  sound  "  all  right, 
and  yet  not  be  firmly  attached  as  supposed.  Besides,  ground 
which  is  perfectly  firm  and  safe  when  first  laid  bare  by  the  miner, 
will  often  lose  its  stability  with  the  lapse  of  time.  Air  and  mois- 
ture penetrating  into  the  minute  concealed  joints  and  acting  for 
months  or  years  have  the  effect  of  gradually  loosening  the  adher- 
ence of  the  rock  masses ;  the  constant  shaking  produced  by 
blasting,  to  say  nothing  of  minute  but  oft-repeated  earth  tremors, 
are  all  acting  in  the  same  way,  and  therefore  the  miner  has  no 
right  to  conclude  that  places  which  were  safe  originally  are  going 
to  continue  so  for  ever. 

Shaft  Accidents. — The  principal  dangers  that  beset  the 
miner  in  shafts  are  manifest  from  the  different  headings,  and 
many  of  the  means  of  guarding  against  them  have  already 
been  explained  in  the  chapters  upon  winding  and  descent  and 
ascent.  It  must  not  be  supposed  that  all  the  accidents  classified 
under  the  third  heading  in  the  British  statistics  occurred  during 
the  ordinary  times  of  going  up  and  down  ;  this  division  also 
includes  fatalities  which  took  place  while  men  were  occupied  in 
making  repairs,  or  were  using  machinery  not  intended  for  the 
purpose  of  raising  men.  The  German  official  statistics  contain 
a  table  in  which  these  irregular  ascents  or  descents  are  eliminated, 
and  make  it  possible  to  institute  a  comparison  between  the  relative 
degrees  of  safety  of  the  different  methods  of  obtaining  access 
to  the  workings.  Judging  by  the  result  of  the  ten  years  1881 
to  1890,  the  death-rate  from  accidents  per  1000  persons  was 
0*060  with  the  cage,  ofo66  with  ladders,  and  0-196  with  the  man- 
engine  ;  this  last  contrivance  is  therefore  far  more  dangerous  than 
the  cage  or  ladders,  although  the  list  of  man-engine  fatalities  was 
not  swollen  by  any  big  catastrophe,  such  as  happened  in  the 
previous  decennial  period.  A  distinction  must  be  made  between  the 
single-rod  and  the  double-rod  machines,  and  the  Prussian  statistics 
include  many  of  the  latter.  It  will  be  readily  understood  that 
a  fall  in  a  naked  shaft  with  few  fixed  platforms  is  far  more  likely 
to  be  fatal  than  a  fall  in  the  shaft  of  a  single-rod  machine,  which 
is  closed  completely  with  the  exception  of  the  small  manholes 
at  intervals  of  1 2  feet.  As  far  as  I  am  aware,  no  accident  on  a 
single-rod  man-engine  in  Cornwall,  even  when  a  rod  has  broken 
with  men  on  it,  has  ever  caused  more  than  one  death  ;  but  there 
are  two  bad  cases  on  record  with  double-rod  engines  in  Germany. 
In  the  year  1880  eleven  men  met  with  their  death  at  Abraham 
mine  near  Freiberg  by  being  precipitated  down  the  shaft  when  one 
of  the  rods  broke  while  they  were  "  riding  "  upon  it.  It  appeared 
from  the  official  inquiry  that  the  timber  rod  had  become  rotten, 

2  Y 


706  ORE  AND  STONE-MINING. 

and  that  it  ought  to  have  been  changed  long  before  the  accident. 
The  other  bad  fatality  was  at  Rosenhof  shaft  near  Clausthal  in  the 
Hartz,  where  again  eleven  poor  miners  were  suddenly  killed  from 
a  similar  breakage.  These  two  accidents  prove  the  incorrectness 
of  the  statement  made  by  those  who  extol  the  man-engine  at  the 
expense  of  the  cage,  and  say  that  no  accident  can  happen  with  the 
former  except  through  the  miner's  own  carelessness ;  but  when 
making  any  such  comparison  it  is  essential  to  know  precisely 
which  kind  of  man-engine  is  meant.  Thus  if  we  take  the  case  of 
Cornwall,  where  the  double-rod  machine  no  longer  exists,  we  find 
just  the  reverse  of  what  appears  in  Prussia.  The  death-rate  from 
accidents  on  man-engines  in  Cornwall  and  Devon  during  the  seven 
years  1873  to  1879*  was  0*14  per  1000  persons  using  them,  whilst 
the  annual  death-rate  per  1000  persons  using  ladders  was  higher — 
viz.,  o'2i.  If  the  actual  distance  travelled  had  been  taken  into 
account,  the  scale  would  turn  more  decidedly  in  favour  of  the 
man-engine. 

In  the  Prussian  figures  just  quoted,  the  ladder  appears  but 
little  more  dangerous  than  the  cage ;  probably  most  of  the  mines 
provided  with  ladders  are  much  shallower  than  those  fitted  with 
cages,  so  that  if  the  men  had  been  obliged  to  ascend  from  equal 
depths  in  both  classes  of  mines,  the  list  of  ladder  accidents 
would  no  doubt  have  been  largely  increased. 

The  Belgian  machines,  called  warocqueres  after  their  con- 
structor, are  rendered  safer  than  the  Hartz  or  Saxon  man- 
engines  by  having  a  railing  round  the  back  of  each  platform 
on  the  rods.  Some  of  the  double-rod  machines  are  made  with 
large  platforms,  so  that  two  persons  can  stand  on  them. 

Miscellaneous  Accidents  Underground. — Explosions  of 
Gunpowder,  &c. — Blasting  accidents,  which  head  this -class,  are 
possibly  less  numerous  than  many  people  would  suppose,  when 
reflecting  upon  the  large  quantities  of  gunpowder  and  other  more 
powerful  explosives  which  are  annually  consumed  by  the  miner. 

They  occur  in  many  ways  : 

a.  Accidental  ignition  of  powder,  while  carrying  it  or  handling 
it,  from  a  spark  of  the  candle. 

b.  Getting  in  the  way  of  blasts,  either  from  not  retiring  to  a 
safe  place,  or  from  a  hang-fire  of  the  fuse,  or  from  erroneously 
supposing  that  a  fuse  had  not  been  ignited  by  the  "  snuff." 

c.  Ignition  of  the  charge   during  the  operation  of  tamping. 
Sometimes,  no  doubt,  a  spark  is  struck  by  an  iron  rammer  and 
communicates  fire  to  the  charge  by  a  train  of  powder  lying  either 
behind  the  fuse  or  in  ragged  portions  of  a  hole  bored  in  "  vuggy  " 
ground;   in   other  cases    it    is   thought    that   just    as   German 
tinder  can  be  ignited   by  the   mere   compression  of  air,  so  the 

*  Reports  of  H.M.  Inspectors  of  Mines  for  the  Year  1879,  London,   1880, 
p.  425. 


ACCIDENTS.  707 

charge  itself  may  be  fired  by  hard  ramming  at  the  commence- 
ment. The  number  of  accidents  of  this  class  has  been  reduced 
by  the  introduction  of  the  nitroglycerine  explosives,  which  will 
exert  their  useful  effect  without  hard  tamping. 

d.  Illegally  boring  out  or  picking  out  the  tamping  of  holes 
which  have  missed  fire. 

e.  Exudation  of  nitroglycerine  from  dynamite  left  exposed  to 
water  in  a  hole  which  has  missed  fire.   The  sensitive  oil  may  explode 
when  the  adjacent  rock  is  struck  by  the  pick  or  drill. 

f.  Unexploded  remnants  of  dynamite  or  gun-cotton.     It  occa- 
sionally  happens   that   the  whole   of   a   charge   of   one   of   the 
nitroglycerine   or   pyroxyline   explosives   does   not   go   off  com- 
pletely :   after  firing  a  shot  the  miner  may  find  that  the  blast 
has  not  rent  the  rock  to  the  bottom  of  the  hole,  but  has  left  a 
"socket";  to  save  himself  a  few  inches  of  boring,  he  sometimes 
is  tempted  to  use  this  in  starting  the  next  hole.     Such  proceed- 
ings have  been  proved  to  be  most  dangerous,  for  the  blows  of 
the  steel  tool  may  fire  the  unexploded  remnants,  and  cause  a 
serious  disaster. 

g.  Miners,  and  indeed  others,  have  been  injured  by  the 
explosion  of  the  fulminate  of  mercury  in  the  detonators,  or  caps, 
when  examining  them  incautiously,  or  while  endeavouring  to  pick 
out  sawdust  with  which  they  were  choked. 

The  golden  rule  is  to  treat  explosives  as  substances  which  will 
and  do  explode,  but  it  is  naturally  difficult  for  the  miner  who  is 
handling  them  day  after  day  not  to  become  somewhat  callous  to 
their  dangers. 

Suffocation  by  Gases. — Few  fatalities  in  this  country  are  put 
down  to  suffocation  by  gases  given  off  naturally  by  the  rocks. 

Irruptions  of  Water. — Irruptions  of  water  into  mines  happen 
in  three  ways : 

Floods  at  the  surface  due  to  an  unprecedented  rainfall. 
Extending  the  workings  too  close  to  the  bottom  of  the  sea  or  a  river. 
Breaking  into  old  workings  full  of  water. 

All  these  causes  have  occasioned  disasters  in  mines.  The  first 
danger  may  be  avoided  by  keeping  the  top  of  every  shaft  of  the 
mine  well  above  the  level  of  the  lowest  land  of  the  district.  If 
it  happens  that  the  only  convenient  site  for  a  shaft  is  near  the 
bottom  of  a  valley,  the  top  may  be  built  up  with  masonry  strong 
enough  to  resist  a  flood.  Many  lives  were  lost  in  Hungary  in 
May  1892,  from  the  bursting  of  a  waterspout,  which  caused  water 
to  pour  down  some  mine  shafts. 

Breaking  into  the  flooded  workings  of  old  adjacent  mines  may 
happen  through  want  of  knowledge  or  want  of  care.  Defective 
plans  are  one  source  of  the  irruptions,  the  miner  being  beguiled 
into  a  false  security  by  inaccurate  surveys  of  the  adjacent  property, 
or  by  ignorance  that  any  workings  had  ever  been  made  there  before. 


7o8  GEE  AND  STONE-MINING. 

The  Coal  Mines  Act  enjoins  the  precautions  which  are  well  known 
to  every  miner  in  approaching  old  workings — viz.,  boring  holes  in 
advance  for  the  purpose  of  tapping  the  water,  before  there  is  any 
danger  of  the  protecting  partition  giving  way  under  the  pressure 
behind  it.  The  water  can  then  be  drained  off  slowly,  and  the 
partition  need  not  be  broken  down  until  all  chance  of  flooding  is 


On  Inclined  Planes. — Accidents  may  happen  from  men  being 
caught  and  knocked  over  by  waggons,  while  they  are  making  use 
of  inclines  as  travelling  roads ;  the  statutory  manholes  or  refuge 
niches  are  designed  to  prevent  dangers  of  this  kind,  but  a  better 
plan  is  to  provide  independent  walking  roads,  or  to  partition  off 
the  walking  road  from  the  railroad.  At  some  mines  the  men  are 
prohibited  from  walking  upon  the  inclines  while  trucks  are  being 
drawn  up  and  down,  and  work  is  stopped  at  the  changes  of  the 
shifts,  in  order  to  give  them  the  means  of  descending  and 
ascending  in  safety. 

By  Trams  and  Tubs. — It  would  be  strange  if  men  were  not 
sometimes  injured  when  moving  tram  waggons.  Owing  to  an 
imperfection  in  the  road,  a  waggon  may  turn  over  and  catch  a 
man  in  its  fall,  or  in  narrow  levels  a  man  may  be  nipped  against 
the  side. 

By  Machinery  Underground. — Proper  fences  will  prevent  some 
of  the  fatalities  from  machinery  underground,  and  such  safeguards 
become  all  the  more  necessary  in  the  dark  or  ill-lighted  passages 
of  a  mine,  where  one  may  have  to  assume  a  cramped  position  in 
going  past  the  moving  mechanism. 

Sundries  Underground. — Under  this  heading  will  be  found 
various  accidents  which  cannot  be  placed  in  one  of  the  other  sub- 
divisions. The  most  serious  are  underground  fires ;  in  fact,  two  of 
the  worst  catastrophes  known  in  mining  have  happened  from  this 
cause;  they  are  barely  equalled  by  the  worst  explosions  in  collieries, 
and  go  to  prove  a  fact  already  insisted  on — viz.,  that  coal  mining 
is  not  the  most  perilous  form  of  underground  labour.  I  refer 
now  to  the  underground  fires  at  De  Beers  diamond  mine  and  at 
Pribram.  In  the  year  1888  some  of  the  timber  in  one  of  the 
shafts  at  De  Beers  accidentally  took  fire,  the  flames  spread  rapidly 
and  soon  filled  the  mine  with  smoke  to  such  an  extent  that 
twenty-four  white  men  and  200  natives  were  suffocated.  The 
Pribram  disaster  of  May  1892,  was  on  an  even  larger  scale. 
Again,  some  accident  or  carelessness  caused  the  ignition  of  the 
timber  in  one  of  the  shafts,  and  the  burning  wood  produced 
such  fumes  that  318*  persons  were  asphyxiated  in  the  mine,  whilst 
one  died  a  few  days  after  his  rescue. 

These  are  not  the  only  cases  of  great  disasters  arising  from  fires. 

*  "Der  Grubenbrand  in  Pribram  am  31  Mai  1892,"  B.  u.  h.  Z.,  1893, 

p.  212. 


ACCIDENTS.  709 

At  the  Mauricewood  Colliery,*  in  1889,  sixty-three  out  of  sixty- 
five  men  who  were  in  the  mine  lost  their  lives  through  an  under- 
ground fire,  the  cause  of  which  was  never  precisely  ascertained ; 
possibly  a  naked  light  carried  on  the  head  of  one  of  the  men  came 
in  contact  with  the  very  dry  timbering  on  an  incline  or  with  some 
brattice  cloth,  and  set  it  on  fire.  The  accident  was  in  no  way  due  to 
the  fact  that  the  mineral  worked  was  coal.  Turning  to  ore  mines, 
we  find,  for  instance,  that  fires  have  happened  on  more  than  one 
occasion  in  the  workings  on  the  Comstock  lode.  Before  the  year 
1869  they  fortunately  had  no  other  evil  effect  than  driving  the 
men  out  of  the  workings  ;  but  in  April  of  that  year  a  fire  broke  out 
in  the  8oo-f oot  level  of  the  Yellow  Jack  mine,  possibly  from  a  candle 
left  near  the  timber,  and  it  burnt  along  unnoticed  until  at  last 
a  "  stull "  gave  way  and  drove  a  blast  of  foul  air  and  smoke  into 
the  shafts.  This  happened  at  the  change  of  shifts  and  thirty-four 
miners  were  suffocated. t  After  unsuccessful  attempts  to  rescue 
the  men,  and  when  all  hope  of  their  being  alive  had  been  abandoned, 
steam  was  forced  into  the  mine  two  days  after  the  accident  for 
seventy-two  hours.  This  proved  insufficient,  and  steam  was  again 
forced  in  for  two  days.  The  fire  was  not  completely  subdued  for 
several  weeks,  and  even  six  months  after  the  accident,  smouldering 
timber  was  sometimes  met  with.  According  to  the  experience 
gained  in  this  accident,  steam  is  not  effectual  in  extinguishing  a 
mine  fire,  though  it  is  useful  as  a  temporary  expedient  for  purify- 
ing the  atmosphere  of  the  mine  and  checking  the  flames,  and  so 
rendering  it  possible  to  put  in  dams  and  cut  off  the  supply  of 
oxygen  to  the  conflagration. 

In  addition  to  the  big  catastrophe,  there  were  several  minor 
accidents  of  a  like  nature,  and  forty-nine  persons  in  all  lost  their 
lives  from  underground  fires  at  mines  on  the  Comstock  lode  in 
seventeen  years.  J 

A  fire  at  the  Calumet  and  Hecla  copper  mines  on  Lake 
Superior  in  November  1888  claimed  eight  victims,  and  in  addition 
to  this  loss  of  life  caused  a  considerable  loss  of  money.  Judging 
by  the  accounts  which  are  published  from  time  to  time  in  the 
mining  newspapers,  underground  fires  are  not  so  uncommon  in  ore 
mines  as  one  might  suppose,  and  it  may  often  depend  upon  a  mere 
chance  whether  they  become  fatal  to  life  or  not.  With  a  mineral 
so  easily  ignited  as  native  sulphur,§  the  occurrence  of  fires  in  the 
Sicilian  mines  will  not  excite  astonishment ;  some  of  the  accidents 
arise  from  carelessness  with  lamps  and  in  blasting,  but  the  most 
common  cause  is  the  heat  generated  by  the  friction  of  heavy 

*  Johnston  and  Bell,  "Mauricewood  Colliery,  Report  to  the  Secretary 
of  State  for  the  Home  Department,"  Edinburgh,  1890. 

t  Lord,  "  Comstock  Mines  and  Miners,"  Monographs  U.S.  Geol.  Survey, 
vol.  iv.,  Washington,  1883,  p.  269. 

J  Op.  cit.,  p.  404. 

§  Rivista  del  Servizio  Minerario  nel  1888,  Florence,  1890  p.  70. 


7io  ORE  AND  STONE-MINING. 

masses  of  the  sulphur -bearing  rock  when  there  are  falls,  which,  as 
has  already  been  stated  (Chapter  VI.),  are  sometimes  the  result  of 
the  method  of  working  adopted.  Many  of  the  fires  last  for  a 
very  long  time,  and  in  one  instance  sixty  years  elapsed  before  the 
burning  rock  was  extinguished.  The  number  of  accidents  from 
suffocation  by  sulphurous  acid  produced  by  underground  fires  at 
the  Sicilian  mines  is  by  no  means  small ;  thirty-five  persons 
perished  in  this  way  during  the  five  years  1884  to  1888,  to  say 
nothing  of  four  deaths  from  inhaling  carbonic  acid  gas,  and 
thirteen  deaths  from  sulphuretted  hydrogen.* 

The  moral  to  be  drawn  from  these  unfortunate  accidents  is  that 
at  all  events  the  main  shafts,  or  other  approaches  to  the  under- 
ground workings,  should  be  constructed  in  a  manner  calculated  to 
prevent  a  repetition  of  such  great  disasters.  Many  of  the  shafts 
in  mines,  especially  those  devoted  to  pumping,  are  so  wet  that 
there  is  no  fear  of  a  fire  even  if  they  are  lined  with  timber ;  in 
others  the  lining  is  of  brickwork  or  masonry,  and  the  guides  are 
made  of  steel  rails  or  wire  ropes ;  the  shaft  is  therefore  uninflam- 
mable. In  very  dry  mines,  on  the  other  hand,  the  danger  does 
exist  of  the  shaft  being  converted  by  some  slight  carelessness,  or 
by  an  accident  with  a  lamp,  into  a  huge  blazing  furnace,  which 
may  send  clouds  of  suffocating  fumes  into  the  workings  and  pre- 
vent the  exit  of  the  miners  or  the  entry  of  rescuers.  To  guard 
against  such  a  state  of  things,  either  timber  linings  may  be 
eschewed  and  replaced  by  incombustible  linings,  or  the  inflam- 
mability of  the  wood  may  be  reduced  by  keeping  it  damp.  As 
already  pointed  out,  water  is  in  some  cases  made  to  trickle  over 
the  shaft  timber  in  order  to  prevent  its  being  attacked  by 
dry  rot. 

I  have  dwelt  somewhat  at  length  upon  these  fatalities  from 
fires,  because  of  the  very  serious  consequences  which  have  resulted 
from  them  in  recent  years. 

Before  passing  on  to  the  accidents  which  happen  at  the  surface, 
it  may  be  well  to  call  attention  to  two  recent  rescues  of  entombed 
miners,  as  instances  of  the  length  of  time  men  can  exist  without 
food,  so  that  in  case  of  the  accidental  imprisonment  efforts  to 
recover  the  sufferers  may  not  be  relaxed  too  soon.  In  July  1892 
three  miners  were  shut  in  by  a  fall  at  a  brown-coal  mine  in 
Bohemia,  and  were  rescued  after  the  lapse  of  no  less  than  seventeen 
days,  during  the  whole  of  which  time  they  were  deprived  of  food, 
though  sufficiently  supplied  with  drinking  water.  A  shade  more 
wonderful  is  the  escape  of  four  men  at  Jeansville  in  Pennsylvania,! 
in  February  1891.  Seventeen  persons  were  shut  in  by  the  irrup- 
tion of  water  into  the  mine  from  adjoining  workings,  and  they 
could  not  be  reached  until  the  level  of  the  water  had  been  lowered 
by  pumping.  When  the  rescuers  were  able  to  penetrate  into  the 

*  Op.  cit.,p.  54. 

f  Eng.  Min.  Jour.,  vol.  li.  1891,  p.  447. 


ACCIDENTS.  7n 

workings,  eighteen  days  after  the  disaster,  four  of  the  seventeen 
men  were  found  alive,  though  of  course  extremely  weak. 

Accidents  on  the  Surface. — By  Machinery. — A  very  large 
proportion  of  the  surface  accidents  are  such  as  might  happen  at 
any  factory.  Though  they  cannot  be  prevented  entirely,  for  men 
and  boys  will  sometimes  go  into  the  most  unexpected  places,  much 
good  can  be  done  by  fencing ;  and  it  is  always  well  to  err  upon 
the  side  of  over-caution,  and  protect  shafting  or  other  moving 
parts  which  may  at  first  sight  seem  quite  innocent.  If  the 
lubricant  cannot  be  supplied  by  one  of  the  constant  feeders,  the 
attendant  should  do  the  oiling,  as  far  as  possible,  when  the 
machinery  is  stopped  for  meal-times  or  for  some  other  purpose ; 
the  desirability  of  wearing  tightly  fitting  clothes  has  already  been 
mentioned,  and  it  is  always  advisable  to  have  the  means  of 
throwing  machinery  out  of  gear  quickly,  in  case  a  person  is  caught 
by  it. 

For  putting  belts  on  to  pulleys,  a  special  "  shipper  "  is  safer  than 
the  hand. 

Now  that  so  many  mines  have  circular  saws,  it  is  well  to 
recollect  that  the  use  of  a  guard,  like  the  Lakeman  guard  for 
instance,  may  occasionally  save  a  man  the  loss  of  a  finger  or  a 
hand. 

Looking  at  the  fact  that  millions  of  slates  that  are  made  annually 
by  machines  with  revolving  or  guillotine-like  knives,  it  is  not  strange 
that  through  momentary  inadvertence  men  should  now  and  then 
put  the  hand  in  a  little  too  far  and  lose  the  end  of  a  finger.  It  is 
impossible  for  any  mortal  to  be  continually  on  the  watch  against 
such  occurrences  as  these,  hour  after  hour  and  day  after  day,  and 
the  marvel  really  is  that  in  spite  of  distractions  the  human  machine 
works  as  correctly  as  it  does. 

Boiler  Explosions. — The  subject  of  boiler  explosions  concerns 
the  general  manufacturer  quite  as  much  as  it  does  the  miner, 
and  it  has  been  so  thoroughly  studied  of  late  years  that  there 
is  no  longer  any  reason  for  ascribing  such  occurrences  to  mys- 
terious and  inexplicable  causes.  Boilers  burst  from  weakness, 
which  may  be  due  to  original  malconstruction,  to  improper 
treatment,  or  to  ordinary  wear  and  tear.  It  is  very  desirable 
that  every  boiler  should  be  cleaned  out  at  least  once  in  three  months 
and  then  carefully  examined  internally,  a  record  being  kept  at  the 
office  signed  by  the  person  making  the  inspection.  In  England, 
very  many  owners  of  boilers  join  such  a  society  as  the  Manchester 
Steam  Users  Association  and  have  their  boilers  periodically 
inspected  by  competent  experts,  who  at  the  same  time  are  able 
to  give  many  valuable  hints  concerning  safe  and  economical 
methods  of  working. 

Miscellaneous  on  Surface. — Under  this  last  heading  are  included 
a  variety  of  accidents,  which  need  no  special  mention. 

It  would  be  interesting  to  know  the  exact  number  of  accidents 


712 


ORE  AND  STONE-MINING. 


FIG.  709. 


which  happen  at  open  works,  but  unfortunately  no  official  figures 
are  published  showing  death-rates  for  the  whole  Kingdom,  such 
as  are  calculated  in  the  case  of  true  underground  mining. 
Judging  by  certain  returns  lately  published,*  it  seems  that  some 
open  quarries  are  decidedly  more  dangerous  than  the  average  mine. 
Non-fatal  Accidents. — Statistics  concerning  non-fatal  acci- 
dents are  of  little  use  unless  the  extent  of  the  injury  is  indicated  in 
some  manner.  The  Mining  Acts  prescribe  that  all  serious  non- 
fatal  accidents,  and  all  accidents  causing  personal  injury  arising 
from  any  explosion  of  gas,  powder,  or  of  any  steam  boiler  shall 
be  reported  to  the  inspector.  In  France,  on  the  other  hand,  the 
official  statistics  f  do  not  include  non-fatal  accidents  which  have 
disabled  the  person  for  less  than  three  weeks. 

Mining  is  sometimes  a  source  of  risk  to  the  public  as  well  as  to 
the  actual  workers.  The  commonest  danger  arises  from  unfenced 
or  insecurely  fenced  shafts,  or,  what  are  worse,  shafts  which 
have  been  covered  with  timber  and  earth 
and  become  forgotten.  Every  now  and 
then  the  local  papers  of  mining  districts 
record  the  sudden  and  unexpected  giving 
way  of  a  rotten  "sollar,"  leaving  a 
yawning  crater  in  what  was  thought  to 
be  solid  ground.  Fatal  accidents  to  men 
and  beasts  have  taken  place  in  this 
manner,  to  say  nothing  of  many  very 
narrow  escapes. 

Ambulance  Training. — Though  pre- 
vention is  better  than  cure,  and  though 
the  number  of  casualties  may  be  reduced, 
it  cannot  be  expected  that  mining  will 
ever  be  quite  exempt  from  them.  Pro- 
vision should  therefore  be  made  .to  ren- 
der those  that  do  occur  as  little  harmful 
as  possible.  The  Coal  Mines  Act  of 
1887  compels  the  owners  of  mines  to 
keep  a  supply  of  splints  and  bandages 
ready,  and  many  miners  have  learnt  in 
the  school  of  actual  practice  how  best 
to  assist  their  injured  comrades  before 
the  arrival  of  a  doctor.  Nowadays  the 
establishment  of  classes  under  the  St. 

John  Ambulance  Association^:  has  given  the  men  the  opportunity 
of  acquiring  systematic  instruction  in  the  best  methods  of  ren- 

*  Report  to  Her  Majesty's  Principal  Secretary  of  State  for  the  Home 
Department  by  the  Quarry  Committee  of  Inquiry,  London,  1894,  Parlia- 
mentary Paper  [C. — 7237.] 

t  Statirtique  de  V  Industrie  Minefale  et  des  Appareils  a  vapeur  en  France  et 
en  Alg6rie,pour  VAnnee  1886,  Paris,  1888,  p.  95. 

t  St.  John's  Gate,  Clerkenwell,  London,  E.G. 


ACCIDENTS.  713 

dering  first  aid  to  the  injured,  and  of  moving  them  without 
aggravating  the  mischief  or  causing  needless  pain.  Miners 
all  over  the  world  have  reason  to  be  grateful  to  this  excellent 
Society.  Fig.  709  illustrates  the  "  Furley  "  pattern  stretcher,  as 


FIG.  710. 


supplied  by  the  St.  John  Ambulance  Association,  together  with 
the  "  Lowmoor  Jacket,"  by  means  of  which  an  injured  person 
can  safely  be  placed  at  any  angle.  Figs.  710  and  711  represent  the 
"  Ashford  Litter,"  a  two-wheeled  carriage  for  the  conveyance  of 
the  injured  person  along  roads.  The  former  shows  that  the 

FIG.  711. 


bearers  of  the  stretcher  can  pass  between  the  wheels,  by  stepping 
over  a  crank  axle,  and  so  avoid  lifting  the  heavy  weight  over  the 
wheels.  At  large  mines  there  should  be  a  horse  ambulance 
carriage  for  the  removal  of  sufferers. 

Regular  ambulance  corps  have  been  established  at  some  mines  ; 
probably  the  largest  in  the  United  Kingdom  belongs  to  Colonel 
Seely's  collieries,  already  notable  for  the  aid  given  to  sports  and 
pastimes.  The  corps  now  musters  some  400  men,  or  about  one- 


714  OKE  AND  STONE-MINING. 

tenth  of  the  total  number  of  employes  ;  the  members  wear  a  neat 
uniform  and  are  regularly  drilled.  Many  others  among  the 
workmen,  though  not  belonging  to  the  corps,  have  received 
instruction  in  the  ambulance  classes.  Incalculable  good  is  done 
by  trained  men  of  this  kind,  who  are  ready  on  the  spot  to  render 
first  aid  at  any  moment  to  an  injured  comrade  and  superintend 
his  removal  to  a  hospital ;  the  excellent  example  thus  set  might 
well  be  followed  in  all  mining  districts. 


INDEX. 


ABEL  and  Noble,  on  fired  gunpow- 
der, 209 
Aberllefenny,    method  of  working 

slate  at,  314 

Abyssinian  tube  wells,  137 
Acacia,  228 
Accident  club,  deduction  for,  639, 

690 

Accidents,  carriage  of  injured  per- 
sons, 713 

classification  of,  704 

death-rate  from,  698 

first  aid  in  case  of,  712 

from  explosives,  706 

from  falls  of  ground,  704 

from  underground  fires,  708,  709 

in  boring,  130 

in    coal    mines  and  in    metal 
mines,  700 

in  shafts,  705 

miscellaneous,  underground, 
708 

non-fatal,  712 

on  inclined  planes,  708 

on  the  surface,  711 

societies  for  relief  of  distress 
caused  by,  691 

statistics  of,  698,  703 
Acme  pick,  153 
Acts,  Alkali,  665 

Boiler  Explosion,  666 

Brine,  Pumping,  666 

Coal  Mines  Kegulation,  662 

Elementary  Education,  666 

Employers'  Liability,  666 

Explosives,  666 

Factory  and  Workshop,  667 

Metalliferous  Mines  Regulation, 
656 

Quarry  Fencing,  667 

Rating,  655 

relating  to  Derbyshire,  655 


Acts — continued. 

relating  to  Forest  of  Dean,  655 
Rivers     Pollution    Prevention. 

667 

Slate  Mines,  659 
Stannaries,  668 
Truck,  668 

Adelaide  drill,  195 

Adit,  Atlantic-Pacific,  437 

Blackett    level,    Northumber- 
land, 435 

Cornwall  County,  435 
drainage  by,  433 
Ernst  August  Stolln,  434 
Halkyn  tunnel,  435 
Kaiser  Josef  II.,  Pribram,  434 
Kaiser  Josef  Erbstolln,  434 
Mansfeld  copper  mines,  434 
Monteponi,  Sardinia,  435 
Rothschonberger  Stolln,  434 
Sutro  Tunnel,  Nevada,  436 
working  deposit  by,  308 

Advantages  of    steel   supports  for 
levels,  257 

Adventitious      finds    of     valuable 
minerals,  95 

Aerial  ropeways,  380 
incline,  406 

Agglomeration,      preparation      for 
market  by,  565 

Air,  causes  of  pollution  of,  480 
composition  of,  475 
evil  effects  of  dust  in,  685 
friction  of,  510 
measuring  velocity  of,  506, 

507 

testing  the  quality  of,  498 
Air-brake    for    self-acting    incline, 

Bilbao,  376 
Air-compressors,  164 
Angstrom's,  165 
Burckhardt  and  Weiss,  166 
dry,  1 66 
Hanarte's,  165 


7i6 


INDEX. 


A  ir-compressors — continued. 

Ingersoll-Sergeant,  167 

injection,  166 

water-column,  165 
Air-current,  resistance  to,  510-512 
Air-drying,  592 
Air-hose,  171 
Air-lock,  278 
Air-mains,  170 
Air-pipe    for     ventilating    shallow 

shafts,  488 
Air-reservoir,  168 

underground,     advantages    of, 

169 

Air-sollar,  486 

Air-space  required  per  man,  674,  676 
Alabaster,  occurrence  of,  in  Italy, 

51 

Algachi  silver  mines,  cold  at,  669 
Algeria,  discovery  of  phosphate  of 

lime  in,  96 

Alkali  Acts  as  affecting  mines,  665 
Alluvial  beds,  mode  of  working,  291 

diamond  deposits,  39 

gold-mining,  California,  318 

tin  ore  deposits,  85 

method  of  working,  316 
Almaden,       mercurial       poisoning 
among  miners,  687 

mine,  72 
Alta,  definition  of,  1 1 

in  quicksilver  mines,  73 
Altenberg,  calamine  deposit,  19 

Saxony,  tin  stockwork  at,  84 
Alum-stone,  20 
Alunite,  20 

Amalgam,  retorting  of,  598 
Amalgamation,  616 
Amber,  dressing  of,  618 

liquefaction  of,  598 

mode  of  occurrence,  21 

working  for,  304 
Ambulance  corps,  713 

training,  712 
American  phosphate  kiln,  594 

pitch  pine,  227 

system  of  boring,  137 
Ammonite,  215 
Ammeberg,  Sweden,  beds   of    zinc 

blende  at,  87 
Amorpha  canescens,  104 
Amygdaloid,      copper-bearing,      of 

Lake  Superior,  35 
Anaconda  Mine,  Montana,  37 

gozzan,  1 02 
Andreasberg,  St.,  man   engine  at, 

535 

Anemometers,  507 
Angers,  arc-lamp  at,  524 


Angers — continued. 

slate  mining,  314 
Angle  for  ladders,  530 
Angstrom's  air-compressor,  165 
Animals  as  indicators,  105 
Anomalies  in  mineral  repositories, 

17 

Anticlinals,  47,  48 
Antimony  ore,  liquation  of,  598 

mode  of  occurrence,  21 
Antiseptics  applied  to  timber,  230 
Anzin    collieries,   France,    shower- 
baths,  68 1 

steel  frames,  259 
Arc-lamp  at  Angers,  524 

Maros-Ujvar,  524 

Mechernich,  524 

Osceola  Co.  's  Mine,  525 

Kio  Tinto,  525 
Ardennes,  method  of  mining  slate, 

3H 

Arizona,  copper  in,  37 
Armstrong's  electric  signalling,  533 
Arrastra,  556,  618 
Arrault,  free-falling  tools,  129 

on  boring  rods,  125 
Arsenic,  preparation  of,  619 

flues,     clothing     worn     when 

clearing  out,  673 

Arsenical    minerals,   effects   of  in- 
haling dust  from,  686 
ores,  calcination  of,  611,  613 
mode  of  occurrence,  21 
sores,  686 

Arsenious  acid,  preparation  of,  619 
Artificial  ventilation,  490 
Aruba  Island,  origin  of  phosphate 

of  lime  at,  69 
Asbestos,  dressing  of,  619 

mode  of  occurrence,  21 
Ascensional  theory  of  formation  of 

mineral  veins,  15 
Ascent,  526 

Ashburner    on  the   occurrence    of 
natural  gas  in  the  United  States, 

59 

Aspen  case,  9 

Asphaline,  211 

Asphalt,  dressing  of,  619 
mode  of  occurrence,  22 
rock,  preparation  for  sale,  598 

Association  of  minerals,  97 

Atkinson,  Messrs.  L.  &  C.,  on  elec- 
tric transmission  of  power,  172 

Atlantic  Copper    Mine,    Lake   Su- 
perior, 37 

Atlantic-Pacific  Tunnel,  437 

Atlas  powder,  214 

Atmospheric  weathering,  610 


INDEX. 


717 


Attaching  hauling  rope  to  hanger, 

Otto  system,  382 
Attachment  of  rope  to  bucket,  cage, 

&c.,  402 
of  waggons    to    endless   rope, 

368,  379 
Auger,  113 

for  boring  holes   for   blasting, 

154 

stem,  139 
Australia,    candle-holder    used    in, 

515 

trees  used  for  mining  purposes, 

228 

Australian  puddling  machine,  539 
Austria,  graphite  in,  50 

slides  for  descent  used  in,  527 
Automatic  dumping  cage,  419 
skip,  412 

stopping  gear  to  prevent  over- 
winding, 424 
water  tank,  Bowden's,  440 

Galloway's,  438 
Axles,  attachment  of,  357 
lubrication  of,  358 


B 


BACK  of  lode,  106 

Backstay,  366,  396 

Bagnall's  sleeper,  352 

Bainbridge,    Emerson,  on    miners' 

cottages,  677 
on  steel  beams,  256 
Baird's  machine,  204 
Baku,  occurrence  of  petroleum  at, 

65 

Ballarat  "  indicators,"  13,  16 
Ball-grinders,  557 
Ball-Norton     magnetic     separator, 

603,  606 
Ball  stamp,  551 
Band- wheel,  138 
Banket,  or  auriferous  conglomerate, 

41 

Barber,  mine,  639 

Barracks  for  workmen,   Kimberley 
Diamond  Mines,  676 

Man sf eld,  674 

Mechernich,  674 

North  Wales,  676 
Barrow  drill,  183 
Barytes,  23 

bleaching  of,  609 

dressing  of,  619 

vein  in  Shropshire,  13 
Batea,  539 
Bath,  workings  for  freestone,  310 


Bath-stone,  41 

Bavaria,  graphite  in,  50 

Baxter's  stone  breaker,  547 

Bearer,  237 

Beaumont's     tunnelling     machine, 

206 

Becker  on  inflammable  gas  in  quick- 
silver mines,  478 
on  the  Comstock  lode,  76 
on    the    interstitial  space     in 

sandstone,  18 
on  the  quicksilver  deposits  of 

California,  71,  73 
on  the  quicksilver  deposits  of 

the  Pacific  slope,  16 
Bed    of    pyrites    at    Kammelsberg 

Mine,  Hartz,  32 
Bed-planks,  405 
Bed-rock,  318 
Beds,  5 

crumpling  of,  88 

faults  and  irregularities  in,  88 

occurrence  of  zinc-blende  in,  87 

recovery  of  faulted  portion,  89 

temporary  pillars,  315 

worked  with  permanent  pillars, 

309 
Bedson  on  the  fumes  produced  by 

roburite  and  tonite,  481 
Bell-box,  131 
Bellite,  215 

Bellom  on  loss  in  dressing,  630 
Bell  pits,  Koumania,  311 
Belt,  Brunton's  endless,  585 

Stem's  endless,  586 
Belts,  picking,  542 
Benching,  311 
Bendigo  gold-field,  47 
Benzine,  in  preparation  of  ozokerite, 

609 

Bertrand  Mill,  work  by  rolls  at,  556 
Bex,  Switzerland,  blower  of  marsh 

gas,  478 

use  of  bosseyeuse,  224 
workings  for  salt,  307 
Bilbao,  iron  ores  of,  102 
Biram's  anemometer,  507 
Bischoff,  Mount,  dressing  tin  ore  at, 

630 

Bishop's  head,  457 
Bismuth    ore,    magnetic    separator 

used  in  dressing  of,  606 
Bit  for  boring  by  hand,  157,  158 
Bits  for  machine  drills,  181 
Bituminous  limestone,  preparation 

of,  598 

Val  de  Travers,  22 

sandstone  in  California,  22 

treatment  of,  619 


LIBRA 
'S  CFTHE 

FT  TO"  T  TT  in  -r-i  ~  ,. 


7i8 


INDEX. 


Biwabik  iron  mines,  discovery  of, 

94 

Blackett  level,  Northumberland,  435 
Blackley,  Kev.  Canon,  on   old  age 

pensions,  694 
Blake's  stone-breaker,  546 
Blanchet,  pneumatic  hoisting  appa- 
ratus, 427 

Blanzy,  boring  ram  at,  187 
Blast,  large,  290,  291 
Blasting,  accidents  from,  706 

explosives  used  for,  209 

gases  produced  by,  48 1 

gelatine,  214 

Knox  system,  162 

laying  dust  produced  by,  685 

oil,  212 

safety  fuse  for,  217 

tools  for  charging  holes  for,  160 

under  water,  fuses  for,  217 

with  gunpowder,  217 

with  nitro-compounds,  218 
Bleaching  barytes,  609 
Blende,  dressing  of,  625,  630 

occurrence  of,  85 

separation  of,  from  iron  pyrites, 

607 

Blondin  for  raising  stone  from  quar- 
ries, 405 
Blount  on  liquid  carbonic  acid  in 

minerals,  476 
Blue-ground,  38 

method  of  working,  De  Beers 

mine,  341 

Bluestone  of  Anglesey,  33 
Boats,  conveyance  by,  372 
Bochkoltz  regenerator,  459 
Bohemia,  dressing  of  graphite  in, 

623 
Boiler  Explosion  Acts,  666 

explosions,  711 
Bolsover  collieries,  miner's  cottage, 

677 

Bonanza,  definition  of,  n 
Booming,  293 
Boots,  672 

worn    by  rockmen,    Festiniog, 

673 
Borax,  23 

lake,  California,  23 
preparation  of,  608 
treatment  of,  in  California,  620 
Bord,  315 

Bore-holes,  conveying  water  to  bot- 
tom of,  187 
deviation  of,  148 
extraction  of  minerals  by,  304 
for    extracting    salt,    Middles- 
brough, 305 


Bore-holes — continued. 
lining  for,  131,  140 
remedying  deviation  of,  130 
removal  of  debris  from,  118,  128, 

141 

surveying,  147 
triangular,  159 
uses  of,  113 
Borers,  157 
Boric  acid,  mode  of  occurrence,  25 

preparation  of,  620 
Boring,  accidents  to  rods,  &c.,  130 
ascertaining  dip  and  strike  of 

strata,  132 

at  Port  Clarence,  137,  142 
by  American  system,  cost   of 

142 
by  percussion  with  rods,  124 

with  rope,  137 
by  rotation,  113 
crown,Docwra's  diamond  setting 

for,  118 

double-handed,  158 
free-falling  tools,  Arrault,  129 

Kind,  130 
hand-power  diamond  drills  for, 

123 

hand  tools  for,  154 
head,  Mather's,  145 
holes  for  blasting,  prevention  of 

dust,  685 

holes  of  elongated  section,  162 
Mather  and  Platt's  system,  142 
method  of  sinking  shafts,  271 
Oeynhausen's  sliding  joint,  128 
pits  for  wire  saw,  205 
portable  set  of  tools  for  hand- 
power,  117 
process  of,  128 
ram  or  bosseyeuse,  186 
rods,  iron,  125 
single-handed,  158 
tools,  127 

with  diamond  drill,  cost  of,  122 
with  the  diamond  drill,  118 
with  wooden  rods,  134 
cost  of,  136 
speed  of,  136 
Boryslaw,  dressing  of  ozokerite  at, 

626 
mode  of  occurrence  of  ozokerite 

at,  64 
safety  gear  for    hauling  men, 

53i 
sinking  shafts  with  windlass, 

388 
steel  rings  for  supporting  shaft 

linings,  265 
Bosseyeuse,  186 


INDEX. 


719 


Bosseyeuse — continued. 

used  for  cutting  groove,  224 
Bower's  coal- cutting  machine,  206 
Bowie,  Hydraulic  Mining,  293 
Bowk,  408 

Brain's  high  tension  fuse,  220 
Brandt's  drill,  178 
Brattice,  487 
Breaker,  Baxter's  stone,  547 

Blake's  stone,  546 

Gates'  stone,  560 

Hall's  stone,  547 

Lester's  stone,  547 

Marsden's  stone,  547 
Breaking  ground,  151 

machines,  uses  of,  564 

up  minerals,  542 

use  of  holes  for,  207 
Breast  boards,  236 
Brick  linings  for  levels,  251 

for  shafts,  252,  267 
Bridge-rails  converted  into  sleepers, 

353 

Bridgman's  ore-sampler,  635 
Brine,  evaporation  of,  609 

Pumping  Act,  666 

wells,  306 

Briscale  (Sicily),  102 
Broach,  201 
Broken  Hill  mines,  78 

cost  of  boring  by  the  diamond 
drill  at,  122 

discovery  of,  96 

lead  poisoning  among  miners, 
687 

outcrop  of  lode,  98 

square  set  timbering,  249 
Brough,    on    concrete    linings    for 
shafts,  254 

on  searching  for  iron  ore  with 

the  magnetic  needle,  112 
Brown  coal  bed  at  Bruhl,  5 
Bruccioni,  100 
Bruckner  furnace,  613 
Bruhl,  bed  of  brown  coal  at,  5 
Brunton's  endless  belt,  585 

furnace,  596,  613 

sampling  machine,  635 

tunneller,  206 
Buchanan,      magnetic      separator, 

604 

Bucket  of  lifting  pump,  448 
Buckets,   for  descent    and   ascent, 

53i 

for  hoisting,  404 
Bucking,  545 
Buddies,  587 

Bulkhead  (hydraulic  mining),  295 
Bull,  158 


Bullahdelah      Mountain,      N.S.W., 
alunite  at,  20 

Bull  engine,  443 

Bullion  mine,  heat  at,  670 

Bullock    Manufacturing    Co.,    dia- 
mond drills,  119 

Bull- wheel,  139 

Bunch  of  ore,  definition  of,  1 1 

Bunning,  330 

Buntons,  237 

Burckhardt    and    Weiss     air-com- 
pressor, 1 66 

Burmah,  oil-fields  of,  65,  66 

working  without  Jight  in,  513 

Butterfly  valve,  453 


C 


CAE  COCH  Mine,  Carnarvonshire,  309 
mode  of  working,  309 
occurrence  of  pyrites,  83 
pumping  with  compressed  air, 

47i 

Cage,   advantages  of  winding  men 
in,  688 

Cam  Brea  mine,  533 

Comstock  lode,  418 

for  descent  and  ascent,  532 

Junge  hohe  Birke  mine,  533 

self -dumping,  419 
Calamine  deposit,  Altenberg,  19,  87 

pansy,  104 

roasting  at  Monteponi,  615 
Calcarone,  for  sulphur  rock,  599 
Calcination  of  arsenic  ores,  611,  613 

clay  ironstone,  6n,  612 

copper  ores,  612,  613 

gypsum,  611,  613 

limestone,  611,  613 

ores,  objects  of,  6n 

tin  ores,  612,  613 

zinc  ores,  612,  615 
Caliche,  62 

mode  of  working,  286 

preparation  of,  608 
California,    bituminous    sandstone 
of,  22 

borax  deposits  of,  23 

drift  mining,  318 

gold  in,  45 

hydraulic  mining  in,  302 

quicksilver  deposits  of,  73 

treatment  of  borax,  620 

and  Consolidated  mines,  heat 

at,  670 
Callon  on    working  salt  marls  of 

the  Salzkammergut,  307 
Calumet  and  Hecla  Mine,  36 


720 


INDEX. 


Calumet  and  Hecla  mine — continued. 

fire  at,  709 

shaft  timbering,  240 

stamps  at,  553 
Canada,  asbestos  in,  21 

nickel  ore  in,  61 
Canadian  system  of  boring,  134 
Cancer  of  lungs  among  miners,  686 
Candle  holders,  514,  515 

used  for  testing  quality  of  air, 

501 
Candles,  sperm  and  composite,  514 

tallow,  513 

Canton  Mine,  lode  at,  8 
Cap,  in  timbering,  232 

on  flame  of  alcohol  lamp,  500 
benzine  lamp,  499 
hydrogen  lamp,  500 
safety  lamp,  499 
Capell  fan,  495 
Capping  ropes,  402 
Capstan  for  hoisting,  388 

for  pumping  machinery,  461 
Caratal  gold-field,  44 

gold  diggings,  birds  at,  105 
Carbolineum,  231 
Carbonas,  84 

Carbonic    acid    gas    conveyed    by 
pipes,  374 

mode  of  occurrence,  25 

in  air,  an  index  of  its  impurity, 
480 

in  the  air  of  mines,  475,  501 

liquefaction  of,  600 

preparation  of,  620 

testing  for,  501 
Cariboo,  timbering  levels,  233 
Carnallite,  occurrence  of,  70 
Cam  Brea  Mine,  winding  men,  533 
Carne,  J.,   definition  of   a  mineral 

vein,  6 

Carrettand  Marshall's  machine,  199 
Carriage  of  injured  persons,  713 

minerals  by  persons,  349,  375 
Carriere,  definition  of,  I 
Carr's  disintegrators,  559 
Cars,  355 
Cartridges,  hydraulic,  208 

lime,  208 

Cartridge- stick,  161 
Casing  boards,  238 
Cassiterite,  minerals  associated 

with,  97 

Cast-iron  columns  used  at  Halkyn 
tunnel,  255 

lining  for  soft  strata,  268 

lining  for  tunnels,  263 

props,  265 

tubbing,  269 


Catches,  460 

Cementation,  616 

Cement  works   affected   by  Alkali 

Acts,  665 
Centrifugal  concentrator,  591 

grinders,56i 
Ceylon,  dressing  of  graphite  in,  623 

graphite  in,  50 
Chains,  401 
Chamberlain,  Mr.  Joseph,  on  State 

pensions,  694 

Chance  discoveries  of   mineral  de- 
posits, 93 

Changing  house,  679 
Channelling  machines,  201 
Chapeau  en  fer,  or  gozzan,  100 
Chapin  iron  mine,  Michigan,  54 
Charging-spoon,  161 
Chase,  magnetic  separator,  60 1 
Chateaugay  Co.,  dressing  magnetite, 

624 
Cheeks  or  walls  of  a  lode,  definition 

of,  10 

Chert,  dressing  of,  622 
Cheshire  mines,  preparation  of  salt, 
628 

jumper  used  at,  157 

salt  mines,  311 

salt  wells,  306 
Chesneau  on  testing  for  firedamp, 

500 

Chilian  mill,  557 

Chilled  cast-iron  shot,  use  of,  for 
boring,  124 

wheels,  357 

Chimney  built  over  shaft   for  ven- 
tilating, 484 
China-clay,  27 

discovery  of,  99 

dressing  of,  620 

drying  of,  592 

workings  in  Cornwall,  292 
Chlorate  mixtures,  211 
Chocks  or  cribs,  245 
Chollar-Potosi  mine,  heat  at.  670 
Chromic  iron  in  New  Caledonia,  28 
Churns,  Forest  of  Dean,  340 
Churprinz  mine,  Freiberg,  spherical 
dam  at,  432 

works,  loss  at,  631 
Chute  of  ore,  1 1 
Cinnabar,  occurrence  of,  71 
Circular  saw  groove-cutters,  202 

used  for  slate,  564 
Clack,  448,  453 

-piece,  448 

seat-piece,  448 
Clanny  lamp,  519 
Clarkson's  rapid  sampler,  634 


INDEX. 


721 


Clarkson  -  Stanfield      concentrator, 

59i 

Classification  of  dressing  processes, 

538 

mineral  deposits,  5 
rocks,  3,  4 

Clay,  26 

Claying  bar,  161 

Clay  ironstone,  calcination  of,  611, 

612 
weathering  of,  6n 

Clays,  dressing  of,  620 

Clay-slant,  222 

Cleaning-up,  hydraulic  mining,  299 

Cleavage  of  slate,  81 

Cleveland,  discovery  of  salt  bed  at, 

96 

district,  royalties  in,  654 
iron-mines,  jumper  used  at,  157 
ironstone,  method  of  working, 

315 
mode  of  occurrence  of,  51- 

Sorby    on    the    origin  of, 

18 

Clevis,  402 
Clifton,    tests    of    light    given    by 

Clanny  lamp,  520 
Davy  lamp,  519 
Climax  drill,  185 
Clinograph,  Macgeorge's,  147 
Clinostat  or  dip-recorder,  147 
Clogs,  672,  673 
Clothing    for    men    engaged    near 

machinery,  673 
of  miner,  669 
worn   when    cleaning    arsenic 

flues,  673 

Clowes  hydrogen  lamp,  500 
Club,  deductions  for  accident,  639 
Coal,  discovery  of,  in  south-east  of 

England,  97 

Coal  Mines  Kegulation  Act,  662 
accident  statistics  under,  700 
tools  for  charging  holes,  161 
Cobalt   mines,    Saxony,    cancer   of 

lungs  among  miners,  686 
ore  in  Flintshire,  discovery  of, 

93 

New  Caledonia,  28 
Ehyl,  Flintshire,  28 
Skutterud,  Norway,  27 
Cobbing,  544 
Coffering,  267 
Cold  at  mines,  669 
Colle  Croce  mines,  Lercara,  Sicily, 

thick  sulphur  seam,  321 
Collieries  affected   by  Alkali  Acts, 
665 


Collins  on  the  china  clay^pi 

wall,  27 
on  the  Great  Mother  Lode  of 

California,  46 

on  the  ores  of  Kio  Tinto,  33 
on    the    pyrites     deposits    of 

Huelva,  32 
Collom  jigs,  621 
Colorado,  lead  ores  of,  57 
lease  system,  647 
sampling  machines  used  in,  634 
tribute  system  in,  647 
Colorados,  100 
Colour  as  an  aid  to  the  prospector, 

99 
Comparative  mortality  figures,  683, 

684 
Compound  for  native  miners,  Kim- 

berley,  677 

engines  for  pumping,  443 
Compressed  air  cartridge,  208 
locomotives,  363 
loss  of  power  from  use  of,  164 
pipes,  170 

pumping  with,  470,  471 
reservoir  169 
sinking  by  aid  of,  277 
stamps,  551 
use    for  ventilating  workings, 

493 

Compressors,  air,  164 
Comstock  lode,  description  of,  76 

discovery  of,  95 

gases  met  with,  476 

gozzan,  i  oo 

heat  on  the,  670 

influence  of    heat  on    health, 
689 

lifting  pump  used  on,  449 

shaft  timbering,  238 

square-set  system  of  timbering, 
246 

timbering  for  levels,  233 
Concentrator,  centrifugal,  591 

Clarkson  and  Stanfield,  591 

Embrey,  586 

Woodbury,  586 
Concrete  blocks,  253 

used  for  lining  levels,  251 

shafts,  253 

Condition  of  miner,  669 
Congenial  beds,  13 
Conglomerate,  copper-bearing,  35 
Conical  grinders,  560 
Conkling  magnetic  separator,  60 1 
Convolvulus  althseoides,  104 
Cook's  Kitchen  mine,  heat  at,  670 
Co-operative  pumping,  474 

societies,  696 

2  Z 


722 


INDEX. 


Copper  at  Lake  Superior,  34 

extraction  of,  in  solution,  307 

precipitation  of,  616 
mines  affected  by  Alkali  Acts, 

665 
ore,    discovery  of    on  Yorke's 

peninsula,  93 
calcination  of,  612,  613 
dressing  of,  621 
in  Germany,  29 
in  Spain  and  Portugal,  31, 

34 

in  the  United  States,  34,  37 
occurrence  of,  28 
separation  from  tin  ore,  609 
Cores,  ascertaining  dip  from,  132 
cutting  out,  1 33 
extractor,  119 

Arrault's,  132 
Bullock's  improved,  121 
modes  of  obtaining,  132 
obtained    by  boring  with  flat 

rope,  147 

produced  in  boring  pits,  205 
tube  for  diamond  drill,  119 
Corf,  derivation  of  term,  405 
Cornish  "  dry  "  for  china  clay,  592 
miner's  boot,  672 

hat,  671 

pumping  engine,  443 
rolls,  553 
Cornwall,     annual     death-rate     of 

miners,  684 
county  adit,  308 
dressing  of  tin  ore  in,  629 
gozzans,  102 
mode  of  occurrence  of  tin  in, 

7,  19,  84 
royalties  in,  654 
tin  lodes  of,  7 
Corrosive  water,  pumps  for,  450 

valves  for,  453 
Cost  of  aerial  ropeway,  385 

antiseptic  treatment  of  timber, 

231 

barracks  for  workmen,  676 
coffering  shaft,  268 
co-operative  pumping,  474 
cottages,  677 
driving  level  at  Bex,  224 
electric  haulage,  372 
lodgings,     &c.,    for    workmen, 

Eisleben,  676 
sinking  through  watery  strata, 

271 
steel   supports  for  levels,  256, 

257 

transport  by   aerial    ropeway, 
386 


Cost  of — continued. 

working  Dolcoath  man-engine, 

working    gold-bearing    gravel, 

California,  320 

Counterbalancing  weight  of  pump- 
rods,  457 

rope  in  winding,  393 
Counterpoise    for    rods,    variable, 

460 
Country,  definition  of  term,  10 

influence  of,  on  lode,  12 
County  adit,  Cornwall,  435 
Course  of  ore,  definition  of,  1 1 
Cox,  S.  H.,  on  an  alunite  deposit  in 

N.S.W.,  20 

on  the  colour  of  vegetation,  104 
Creep,  309 
Crib,  or  curb,  252 
Cross-course,  or  fault,  91 
Crow's-foot,  130 
Crump    and     Brereton's    machine, 

202 
Crusher,  546 

Cornish,  553 
Dodge,  547 
Gates,  560 
Crushing  in   of  workings,   Sicilian 

sulphur  mines,  321 
Crystalline  schists,  3 
Crystallisation,  borax,  608 
nitrate  of  soda,  608 
potassium  salts,  608 
magnesium  chloride,  609 
Cundill,  on  explosives,  209 
Curb,  cast-iron,  267,  270 
Cuvelier's   lock    for  safety  lamps, 

522 
Cyclone  pulveriser,  563 


I) 


DAM,  temporary,  433 

Dams,  masonry,  433 

spherical  wooden,  431 
wooden,  430 

Darkness,  working  in,  513 

Darley,  on  boring  by  rotation,  117 

Darlington  drill,  195 

Daubree  on  the  artificial  formation 
of  minerals,  1 7 

Dauntless  diamond  drill,  119 

Davey's    differential    pumping  en- 
gine, 445,  466 

Davis'  self-timing  anemometer,  507 

Davy  lamp,  619 

Day  Dawn  mine,  pigsty  timbering, 
245 


INDEX. 


723 


Day  Dawn  mine — continued. 
shaft  timbering,  239 
timbering,  234 
Day-level,  433 
Daylight,  working  by  reflected,  in 

California  and  Japan,  513 
Death-rate    of    miners  from  acci- 
dents, 698 
Death-rates,    annual,    for    various 

trades,  684 
De  Beers  diamond  mine,  38 

endless  rope  haulage  at  surface, 

376 

head-gears,  397 
method  of  working,  341 
self  -  discharging     skips,     412, 

415 

washing  machine,  540 
Deep  leads  of  Australia,  85 
Deflection  magnetic  separator,  606 
Deposition  from  solution,  formation 

of  veins  by,  14 
Derbyshire,  Mining  Acts  relating  to, 

655 
Derrick  for  boring    by  percussion 

with  rods,  125,  136 
by  rotation,  117 
with  rope,  137 

Descent  and  ascent  of  miners,  526 
Desiccation  in  dressing,  592 
Detaching  hooks,  422 
Detonators,  216 

strength  of,  219 

Devonshire,  dressing  of  clay,  620 
manganese  ore,  625 
umber,  626 

Diamond,  substitutes  for,  for  drill- 
ing, 124 
Diamond-bearing    rock,  De  Beers, 

dressing  of,  621 
method  of  working,  341 
weathering  of,  610 
Diamond,   discovery    of,    in  South 

Africa,  93 
occurrence  of,  37 
washing  machine  for,  539 
Diamond  drill,  American  Diamond 
Kock  Boring  Company's,  izi_ 
boring  at  Johannesburg,  119 

Northampton,  118 
boring  with  the,  118 
Bullock    Manufacturing    Com- 
pany's, 119,  123 
core  extractor,  119 

Bullock's  improved,  121 
cost  of  boring  by,  122 
crown,  118 
"Dauntless,"  119 
"->/  differential  feed  gear,  119 


Diamond  drill — continued. 

for  boring  holes  for  blasting, 
179,  1 80 

Georgi's  electric,  124 

Little  Champion,  123 

prospecting,  123 

sediment  tube  for,  119 

Sullivan's  prospecting,  124 
»   Swedish  for  hand-power,  123 

thrust  register,  121 

Victorian  "  Giant  Drill,"  121 
Dickinson's  anemometer,  507 

water-gauge,  509 
Diepenlinchen,  pumping  engine  at, 

445 

working  zinc  ore  at,  345 
zinc  ore  stockwork,  87 
Diffusion  of  gases,  485 
Dig,  definition  of,  1 1 
Ding  Dong  mine,  fire-damp  in  level 

at,  477 
Dip,  definition,  5 

influence  of  change  of  on  veins, 

13 

Dipping  needle,  1 1 1 
Discovery  of  minerals,  93 
Diseases  caused  by  arsenical  mine- 
rals, 687 

inhalation  of  dust,  685 

ladder  climbing,  688 

lead  ores,  687 

quicksilver  ores,  687 
Disintegrators,  559 
Distillation,  of  rich  sulphur  rock,  600 

use  in  dressing,  600 
Dividings,  237 
Divining  rod,  1 1 1 
Doctor,  deduction  for,  639 
Docwra,  diamond  setting  for  boring 

crown,  118 
Dodge  Crusher,  547 
Dolcoath  Mine,  Cornwall,  328,  329. 

man- engine,   cost   of  working, 

535 

heat  at,  670 
Dolly,  or  swage,  181 
Dolly  tub,  or  keeve,  5-70 
Dorothea  mine,    Clausthal,   under- 
ground traffic  by  boats,  373 
Double-beat  valve,  454 
Douglas  spruce,  228 
Downcast  shaft,  484 
Downthrow,  91 
Dowsing  rod,  1 1 1 
Drainage,  429 

by  adit,  433 

by  pumps,  441 

by  siphon,  437 

by  winding  machinery,  437 


724 


INDEX. 


Drawing  lift,  448 
Dredges,  175 

grab,  176 

Kincaid  &  McQueen's,  175 

Priestman's  grab,  176 

suction,  177 
Dressing,  definition  of,  537 

amber,  618 

arsenic  ore,  619 

asbestos,  619 

asphalt,  619 

barytes,  619 

bituminous  rock,  598,  619 

blende,  625,  630 

borax,  620 

boric  acid,  620 

carbonic  acid,  620 

chert,  622 

china  clay,  620 

clays,  620 

copper  ore,  621 

diamond -bearing  rock,  621 

flint,  622,  629 

fuller's  earth,  620 

galena,  624,  625 

gold  ore,  622 

graphite,  623 

gypsum,  624 

haematite,  624 

iron  ore,  624 

lead  ore,  624 

loss  in,  630 

magnetite  (see  magnetic  sepa- 
rators), 624 

manganese  ore,  625 

mica,  625 

mispickel,  611,  612,  613,  619 

ochre,  626 

ozokerite,  626 

phosphate  of  lime,  626,  627 

potassium  salts,  627 

quicksilver  ore,  627 

salt,  628 

silver  ore,  628 

slate,  628 

stone,  628 

sulphur  rock,  629 

Trinidad  pitch,  619 

tin  ore,  629 

umber,  626 

zinc  ore,  625,  630 
Drill,  ratchet,  155 
Drilling  rig,-  138 

tools,  139 
Drills,  Adelaide,  195 

automatic  rotation  of,  194 

Barrow,  183 

Brandt's,  178 

classification  of,  183 


Drills — continued. 

Climax,  185 

Darlington,  195 

diamond,  179 

Eclipse,  187,  1 88 

electric  percussion,  198 

Elliott,  154,  155 

for  boring  by  hand,  157 

Franke,  189 

Hirnant,  192 

Ingersoll-Sergeant,  193 

Jarolimek,  179 

Marvin,  198 

Optimus,  189 

percussive,  181 

rotary,  177 

Sergeant,  193 

sharpening,  158,  182 

Steavenson,  180 

steel  for,  182 
Drive-pipe,  140 
Driving  levels,  221 

tunnels  in  soft  ground,  263 
Drums  for  winding,  391 

with  reserve  of  rope,  392 
Dry  compressors,  166 

for  China  clay,  592 

or  changing  house,  679 

rot,  prevention  of,  230 
Drying  of  minerals,  592 
Dubois  and  Francois  air-compressor, 
166 

boring-ram,  186 
Duck  machine,  493 
Ducktown  mine,  Tennessee,  108 

blower  of  sulphuretted  hydro- 
gen, 479 

Dudley,  workings  for  limestone,  311 
Dumb  fault,  87 
Dunbar  and  Euston's  steam  navvy, 

173 

Dust  in  mines,  evil  effects  on  health, 
685 

in  air  of  mines,  482 
Duty  of  the  miner's  inch,  301 

of  pumping-engines,  472 
Dykes,  definition  of,  14 
Dynamite,  213 

danger  from  exudation,  213 

pan  for  thawing  when  frozen, 
213 


E 


EADIE  &  SONS',  joint  for  lap-welded 

pipes,  171 
Eclipse  drill,  188 


INDEX. 


725 


Edge-runners,  556 
Edison's  deflection  magnetic  sepa- 
rator, 606 

second  magnetic  separator,  602 
Education  Acts',  Elementary,  666 

general  and  technical,  682 
Efficiency  of  ventilating  appliances, 

.509 
Eisdeben,    barracks    for    workmen, 

674 
Electric  drill,  Marvin,  198 

Steavenson,  180 

lamp,  Sussmann,  523 

light,  524 

percussion  drill,  198 

railways,  371 
Electricity,  firing  by,  220 

pumps  worked  by,  470 

transmission  of  power  by,  172 
Elementary  Education  Acts,  666 
Elephant  stamps,  551 
Elliot's  locked  coil  wire  rope,  400 
Elliott  drill,  155 

multiple  wedge,  208 
Elwen  on  the    resistance    to    air- 
currents,  511 

Embrey  concentrator,  586 
Emmons,  S.  T.,  on  the  geology  of 
the  Leadville  district,  57 

on    the    veins    in    the    Kocky 

Mountain  region,  7 
Employers'  Liability  Act,  666 
Ems,  loss  in  dressing  at,  631 
End,  ventilation  of  an,  485,  487, 492, 

493 

going  into,  after  blasting,  686 
Endless   chain  system  of  haulage, 

37i 

rope  system  of  haulage,  367 
advantages  of,  369 
attachment  of  waggons  to, 

368,  379 

De  Beers  mine,  378 
End-piece,  237 
Equilibrium  pipe,  274 
Erigonum  ovalifolium,  104 
Ernst  August  Stolln,  434 
Eucalyptus,  species  used  for  mining 

purposes,  229 
Eureka,  Nevada,  silver-lead  deposits 

of,  77 

square-set  timbering,  247 
Europe,  trees  used  for  mining  pur- 
poses, 227 
Eustice,  changing  house  at  Levant 

Mine,  Cornwall,  679 
Evans  and  Veitch,  pump  for  raising 

water  by  compressed  air,  471 
Evaporation  of  brine,  609 


Excavating  by  water,  226 

machinery,  173 

Excavation  of  minerals  underground, 
308 

under  water,  302 
Excavations,  supporting.  227 
Exploitation,  285 
Explosions  of  fire-damp,  476,  477 
Explosives,  accidents  from,  707 

strength  of,  216 

used  in  mining,  209 
Explosives  Act,  666 
Extraction  of  minerals  by  wells  and 
boreholes,  304 


F 


FACTORY  and  Workshop  Acts,  667 
Fahlbands  at  Kongsberg,   Norway, 

12 

Falls  of  ground,  accidents  from,  704 
Falun,  torches  used  at,  515 
Fans,  Capell,  495 
efficiency  of,  509 
Guibal,  496 
Schiele,  497 
use  of,  in  dressing,  590 
Waddle,  497 
Faults,  87 

length  of,  90 

measurement  of  throw  of,  89 
recovery  of  lost  part  of  bed,  89 
recovery  of  lost  part  of  lode  or 

vein,  91 
reversed,  90 
variations  of  throw  along  the 

strike,  90 
Feeders  or  droppers,  definition  of, 

12 

Fencing  Act,  Quarry,  667 
Fend-oft'  bob,  446 

Fernow  on  the   trees  available  for 
mining   purposes  in  the   United 
States,  228 
Festiniog,   boot  worn  by  rockman, 

673 

method  of  working  slate  at,  312 
preparation  of  slate  at,  628 
slate    mines,    charging    spoon 

used  at,  161 
drivages  at,  222 
jumper  used  at,  157 
tribute  system  at,  649,  651 
Field,  Mr.  Justice,  on  the  Kichmond 

v.  Eureka  case,  8 
Filling  up,  working  with  complete, 

322,  331,  335,  341,  343,  346 
Fir,  Scotch,  228 


726 


INDEX. 


Fire-clay,  26 

weathering  of,  611 
Fire-damp  found  in  ore  mines,  476 

testing  for,  498-501 
Fireless  locomotives,  363 
Fires,  accidents  from  underground, 
708,709 

in  sulphur  mines,  Sicily,  321 
Fire-setting,  225 
Firing  by  electricity,  220 

explosives,  218 
Firth's  pick  machine,  199 
Flare  lamp,  516 

Flat-rope,  winding  with  the,  393 
Flattened  strand  wire  rope,  400 
Flint,  dressing  of,  622 

mining  at  Brandon,  Suffolk,  41 
Flints,  shaping  of,  629 
Floating    reef    in    Kimberley    dia- 
mond mines,  38 

Flooded  workings,  breaking  into,  707 
Flookan,  explanation  of  term,  14 
Floor  of  a  bed,  definition  of,  5 

of  changing  house,  68 1 
Florida,  phosphates  of,  69 
Flume,  294 
Fluted  rolls,  556 
Foot-wall,  definition  of,  10 
Forest  of  Dean,  method  of  working 
haematite  masses,  340 

Mining  Acts  relating  to,  655 
Form  for  pump  bucket,  448 
Form  of  the  ground  indicating  de- 
posits, 98 

Formation  of  mineral  veins,  14 
Formations  or  classes  of  lodes,  17 
Foxdale  lead  mine,  carbonic  acid 
at,  475 

mode  of  working  lode,  335 

strike  of  lode,  14 
Frames,  579 

for  levels,  steel,  260 

wood,  233 

for  shafts,  236 
France,  underground  workings  for 

slate,  314 
Franke  drill,  189 
Franke's  mechanical  chisel,  199 
Free-falling  tools,  Arrault,  129 

Kind,  130 

Free-milling  ores,  101 
Freestone,  41 

mode  of  working,  310 
Freezing  method  of  sinking  shafts, 

278 

Freiberg,  formations  of  lodes  at,  17 
French  miner's  hat,  671 
Friability,  use  of  in  dressing,  607 
Friction  due  to  sides  of  airway,  510 


Frongoch  jigger,  573 

self-discharging  skip,  416 

separator,  576 
Frozen  dynamite,  213 
Frue  vanner,  585 

for  gold  ores,  622 
Fuller's  earth,  27 

dressing  of,  620 

kiln,  595 
Furnace,  Brunton's,  596,  613 

roasting,  611 

ventilation,  490 
Furness    district,    temporary    dam 

used  in,  433 
Fuse,  electric,  220 

for  blasting  purposes,  217 

for  simultaneous  blasting,  220 


GAD,  154 

Galena,  dressing  of,  624,  625 

Galicia,  Canadian  system  of  boring 

in,  134 
ozokerite  mines  of,  63 

Galloway  on  the  fire-damp  cap,  499 

Galloway's  automatic   water  tank, 

438 

double  walling  stage,  409 
method  of  guiding  kibble,  408 
pneumatic  water-barrel,  438 
steel  tram,  359 
winding  drum,  392 

Garfield  Mine,  California,  79 

Garland,  267 

Gamier,  discovery  of  nickel  ore  in 
New  Caledonia,  99 

Gas  for  underground  lighting,  522 

Gases  produced  by   decomposition 

of  gun-cotton,  215 
of  nitro-compounds,  212 
explosion  of  gunpowder,  210 
blasting,  481 

Gates  crusher,  560 

Gatzschmann,  on  animals  as  indica- 
tors, 105 

Gearing  pump-buckets,  448 

Geikie,  Sir  A.,  definition  of  a  mineral 
vein,  6 

Gelatine  dynamite,  214 

Gelignite,  214 

Geology  as  a  guide  to  minerals,  97 

German  miner's  hat,  672 

Germany,  amber  dredging,  304 
carbonic  acid  gas  in,  25 
copper  deposits  of,  29 
death-rate  from  accidents,  699 
Law  of  Insurance,  694 
occurrence  of  zinc  ore  in,  87 


INDEX. 


727 


Gerolstein,  borings  for  carbonic  acid 

gas  at,  25 
Giant  granite,  58 

mines,  290 

powder,  214 

Gillott  and  Copley's  machine,  203 
Gill's  furnace  for  sulphur  extraction, 

600 

Githens  system  of  boring,  162 
Gobert's  modification   of  Poetsch's 

freezing  process,  283 
Gold,  amalgamation  of,  616 

associated  minerals,  97 

in  gozzan,  100 

modes  of  occurrence,  4 1 

ores,  treatment  of,  622 

Run  Ditch  and  Mining  Co. ,  302 

worked  in  Alps  by  Romans,  618 
Gold-bearing     gravel,     method    of 
mining  in  California,  318 

prospecting  for  in  Siberia,  278 

working,  293 

yield  of,  302 

Good  conduct,  premiums  for,  652 
Gooseneck,  402 
Gouge,  definition  of,  n 
Gozzan,  99 

at  the  Anaconda  mine,  37 

at  Rio  Tinto,  33 

influence  of,  on  value  of  ore,  101 
Graphite,  50 

dressing  of,  623 

in  Bavaria,  607 
Gravitation  stamps,  548 
Great  Basin,  borax  deposits  of  the, 

23 

Greathead  shield,  263 
Great  Laxey  Mine,  locomotive,  363 

overshot  wheel,  442 
Great   Quartz  Vein    of    California, 

length  of,  1 1 
outcrop  of,  99 
Great    Western    quicksilver    mine, 

California,  74 
outcrop  of  lode,  98 
Greaves'      circular      slate-dressing 

machine,  565 
Grey  box,  229 
Griffith,  on  coffering,  268 
Grime's  graves  or  ancient  workings 

for  flint,  41 
Grimm,  definition  of  a  mineral  vein, 

6 

Grinders,  Grusonwerk  ball,  557 
ball,  557 
centrifugal,  561 
conical,  560 
Jordan's,  557 
/See  also  tinder  CEUSHEES 


Grizzly,  299 
Groove-cutters,  201 
Groove-cutting  machines,  199 
Grooves  cut  by  circular  saw,  202 

travelling  rock  drill  or  jumper, 
20 1 

made    by  endless    chain  with 
cutters,  204 

revolving  bar  with  cutters,  206 

wire  saw,  204 

Grusonwerk  ball  grinder,  557 
Gudgeon,  457 
Guibal  fan,  496 
Guides  for  shafts,  408 
Guillotine    slate-dressing    machine, 

5.65 

Guinotte,  pumping-engines  with  fly- 
wheel, 444 

Gun  for  clearing  bore-holes,  160 

Gun-cotton,  215 

products  of  decomposition,  212, 

215 
Gunpowder,  209 

charging  holes  with,  217 

products  of  explosion  of,  210 
Gunpowder  Act,  Slate  Mines,  659 
Gutta-percha  packing  for  pump, 

448 

Gympie  gold-field,  lodes  of,  13 
Gypsum,  50 

calcination  of,  611,  613 

discovery   of,    by  sub-wealden 
boring,  near  Battle,  96 

dressing  of,  624 

occurrence  of,  50 

quarries,  Paris,  309 


H 


HAASE  process  of  sinking  shafts,  283 
Habets  on  annual  death-rate  from 

accidents,  699 
Hade,  definition  of,  9 
Haematite  at  Iron  Mountain,  Mich- 
igan, 54 

deposits  of  the  Ulverston  dis- 
trict, 19 
dressing  of,  624 
method  of  working,  340,  343 
searching  for  by  piercing,  106 
veins   of    the    Lake    District, 

Kendall  on,  7 
Haeuser    process    for  sinking     in 

quicksand,  284 

Haggle's  patent  Protector  rope,  400 
Hake's  mouth  valve,  453 
Hale  and    Norcross  mine,  heat  at, 
670 


728 


INDEX. 


Half-moons,  448 

Halkyn  Drainage  Tunnel,  223,  435 

iron  supports,  255 

Halkyn  Mine,  Flintshire,  slickenside 
at,  10 

wooden  pulley-frame,  395 
Hallett,  Judge,  on  the  Aspen  Case, 

9 

Hall's  stone-breaker,  547 
Hammer,    of   Mansfeld,  on   lifting 
beam   of     pumping    engine, 
461 

on  the  friction  of    guides  for 

pump  rods  in  shaft,  473 
Hammers  for  boring  by  hand,  159 
Hanarte's  air-compressor,  165 
Hand-barrows,  375 
Hand- drilling,  157,  160 
Hand-picking,  541 
Hand-power  diamond  drill,  123 

rotary  drills,  155 
Hand-sampling,  632 
Hand-sieves,  566 
Hand-tools,  151 
Hang- fire,  217 

Hanging  wall,  definition  of,  10 
Haniel  and  Lueg's  keps,  419 
Hurting   and    Hesse,  on  cancer  of 

lungs  caused  by  dust,  686 
Hartz  blower,  493 

Ernest  Augustus  adit,  434 

foreman's  lamp,  516 

iron    rails    used    as    supports, 

..258 

Jig.  570 

miner's  lamp,  515 

timbering  chamber  for  water- 
wheel,  241 

timbering  for  shaft,  240 

use  of  water  power,  442 
Harvey  on   the  occurrence   of    ni- 
trate of  soda  in  Chili,  62 
Hat,  Cornish  miner's,  671 

French  miner's,  671 

German  miner's,  672 

ideal  miner's,  672 

ironstone  miner's,  671 

Mansfeld  miner's,  672 

Koumanian  miner's,  672 
Hatches,  389 
Haulage,  348 

electric  railways,  371 

endless  chain,  371,  379 

endless  rope,  367 

horses,  362 

locomotive,  363 

main  and  tail  rope,  366 

single-rope  system,  365 
Head-gear,  394 


Heat  at  mines,  670 

of  mines  on  Comstock  Lode,  76 
of     workings,     influence      on 

health,  689 

Heated  floors,  drying  on,  592 
Heave,  88 

of    vein    sideways    caused   by 

slip  along  line  of  dip,  91 
Heavy  spar,  bleaching  of,  609 

occurrence,  23 

Heights  (N.  Lancashire),  344 
Hepplewhite-Gray  lamp,  521 
Hercules  powder,  214 
Hesse's  method  of  testing  the  air, 

503»  505 

Himmelfahrt  works,  loss  at,  630 
Hirnant  drill,  192 
Hirt,  on  prevention  of  illness  from 

arsenic,  686 
Hitches,  154,  231 
Hockin   and   Oxland  calciner,  613, 

6i5 

Hoffman  magnetic  separator,  602 

Hofmann  kiln,  613 

Hoisting,  387 

Holes,  arrangement  of,  for  driving 
and  sinking,  222,  225 

Holway  Consols  mine,  explosion  of 
fire-damp,  476 

Honigmann,  soda  locomotive,  364 

Honningen,  carbonic  acid  gas  at,  25 

Hopper  of  hydraulic  elevator,  300 

Hoppet,  408 

Horned  sets,  233 

Horse  in  lode,  definition  of,  1 1 
-whim,  389 

Horses,    underground   hau-lage  by, 
362 

Hospitals,  695 

Hot  springs,  476 

Hottinguer  shaft,  Blanchet's  pneu- 
matic hoist  at,  428 

House,  changing,  679 

Housing  of  workmen,  673 

Howard's  steel  sleeper,  352 

Ho  well's  steel  tube  prop,  266 

H-piece,  451 

Huanchaca  silver  mines,  78 

Huelva,  port  of,  380 

Hund,  351 

Huntington  mill,  561 

Hurricane  lamp,  516 

Hurry,  344 

Husband's  stamps,  551 

Hushing,  106 

Hydraulic  cartridge,  208 
drill,  1 80 
elevator,  300 
lock  for  safety  lamps,  522 


INDEX. 


729 


Hydraulic— continued. 
mining,  226,  292 
power,  171 

for  breaking  ground,  163 
transmission  of  power,  469 
Hydrogen  flame  used  in  testing  for 
fire-damp,  500 


I 

ICE,  51 

Iceland,  mode  of  occurrence  of  sul- 
phur in,  82 
Idria,  occurrence  of  quicksilver  ore 

at,  72 
treatment  of  quicksilver  ores, 

627 

Illicit  Diamond  Act,  677 
Incandescent  lamps  in  shaft  sinking, 

524 

portable,  523 

Inclination  of  a  level,  effect  of,  on 
ventilation,  485 

of  underground  road,  355 
Incline,  natural  ventilation  of,  486 
Inclined  planes,  accidents  on,  708 

underground,  362 

shafts  sunk  on  lode,  225 
Inclines,  308 

self-acting,  376 
Indications  of  tire-damp,  498 
Indicative  plants,  103 
Indicator  for  winding  engines,  421 
Indicators  at  Ballarat,  13,  1 6 
Inflammable  gas,  59,  476 
Ingersoll  bar-channeller,  201 

-Sergeant  air-compressor,  167 
Injection  compressors,  166 

of  veins,  14 

Intersection  of  veins,  1 1 
Inversion  of  strata,  88 
Inverted  saddle-reefs  of   Victoria, 

47 
Iron  and  steel  supports  for  levels, 

255 

shafts,  263 
working  places,  265 
Iron-bark,  229 
Iron  hat,  or  gozzan,  100 
Iron  ladders,  529 
Iron  mines,  Forest  of  Dean,  method 

of  working,  340 

N.  Lancashire,  method  of  work- 
ing, 343 

Iron  ores,  dressing  of,  624 
occurrence  of,  51 
Northamptonshire   open  work- 
ings, 286 


Iron  pump-rods,  Shakemantle  mine, 

461 

Iron  pyrites,  Carnarvonshire,  83 
Iron  rails  used  for  supporting  roof 

of  level,  256,  259 
Iron    rings    for    supporting    shaft 

linings,  263 

Iron  rods  for  boring,  124 
Ironstone  blows  (Australia),  100 
Ironstone,   method  of  working  in 

Cleveland  district,  315 
miner's  cap,  671 

Irruptions  of  water  into  mines,  707 
Irving  on  the  copper  veins  of  Lake 

Superior,  36 
Itabirite,  40 
Italy,  alabaster  in,  51 
asbestos  mines  of,  21 
boric  acid  in,  25 
carbonic  acid  gas  in,  26 
marble  in,  58 
mining  law  in,  i,  2 
mode  of  occurrence  of  sulphur 
in,  82,  83 


JACK,  on  the  Mount  Morgan  gold 
deposits,  48 

on  the  outcrop  of  gold  veins  in 

Queensland,  98 
Jacobi's  stove,  597 
Jacomety   and    Lenicque's  separa- 
tors, 575 

table,  583 

trommel,  567 
Jacotinga,  44 
Jad,  310 

Jagersfontein  diamond  mines,  39 
Jan  Ham's  clack,  453 
Japan,  torches  used  in,  515 

working  by  reflected  daylight 

in.  5»3 

Jarolimek's  drill,  179 

Jarrah,  228 

Jars,  140 

Jaw-breakers,  546 

Jigger,  570 

pneumatic,  589 

Jiggers,  discharge  of,  572 

Jog,  237 

Johannesburg,  deep  boring  at,  119 
gold-bearing  rocks  of,  42 
thickness  of  beds  of  auriferous 
conglomerate,  5 

Joint  for  wooden  rods,  445 

Jordan's  grinder,  557 


730 


INDEX. 


Jumper,  157 

Jtmge  hohe  Birke  mine,   cage  at, 
533 


KAINITE,  occurrence  of,  70 
Kaiser   Josef    Erbstolln,    Hungary, 

434 

Kaiser  Josef  II.  adit,  Pribram,  434 
Kauri     gum,     searching     for      by 

piercing,  106 
pine,  229 

Keeve,  or  dolly-tub,  570 
Kendall  on  the  geology  of  the  Cleve- 
land district,  41 
on  the  hasmatite  veins  of  the 

Lake  District,  7 

Kennedy  on  the  efficiency  of  com- 
pressed air,  164 
Keps,  419 

Kessler,  magnetic  separator,  602 
Kibble,  404 
Kieselguhr,  213 
Kiln,  American  phosphate,  594 
fuller's  earth,  595 
Hofmann,  613 
Kilns  for  drying,  594 
Kimberley  diamond  district,  37 

mines,    compound    for    native 

workmen,  677 
method  of  working  at  De  Beers, 

Kincaid    and    McQueen's    bucket 

dredger,  175 
Kind,   free-falling  tool  for  boring, 

130 
-Chaudron  process    of   sinking 

shafts,  271 

recent  modifications,  276 
King  and  Humble's  detaching  hook, 

422 
King,ori  the  "indicators " at Ballarat, 

13 

on  the  Comstock  Lode,  76 
King-post,  457 
King's     magnetic     separator,     604, 

606 

Kitto,   Paul  and   Nancarrow,   self- 
discharging  skip,  416 
Knots    in    the   lead-bearing    sand- 
stone at  Mechernich,  55 
Knox  system   of   boring  holes  for 

rending  stone,  162 
of  charging  holes,  220 
Kongsberg  silver  mine,  fire-setting, 

225 

silver  veins  of,  12 
Korea,  fire-setting  in,  225 


Kreischer  and  Winkler  on  the  ap- 
pearance of  the  fire-damp  cap,  499 
Krom  rolls,  554 
Krom's  stove,  595 


LABOUR,  principles  of  employment 

of  mining,  637 
Ladder-climbing,  diseases  caused  by 

excessive,  688 
Ladders,  527 
iron,  529 
Lagging,  233 

Laidler's  sector  wire  rope,  401 
Lake  Superior,  copper-bearing  dis- 
trict of,  34 
iron  ores  of,  54 

mines,  stamps  used  at,  551,  553 
treatment  of  copper  ore  at,  621 
La  Louvifcre  mine,  Belgium,  467 
Lamm  and  Franck's  fireless  locomo- 
tive, 363 

Lamp,  electric,  523 
flare,  516 

Hartz  foreman's,  516 
Hartz  miner's,  515 
Hurricane,  516 
magnesium  ribbon,  517 
Mansfeld,  516 
safety,  518 
Saxon  miner's,  516 
Scotch,  516 
Sicilian,  515 
United  States,  516 
Lander,  410 
Lang's  wire  rope,  400 
Larch  for  timbering  excavations,  227 
Lashings,  237 
Latch    and    Batchelor's    flattened 

strand  wire  rope,  400 
Lateral  secretion  theory  of  forma- 
tion of  mineral  veins,  15 
Laths,  243 
Lawn,  on   searching  for  haematite 

in  the  Furness  district,  106 
on  working  haematite  in  North 

Lancashire,  343 

Laxey  mine,  locomotive  at,  363 
man-engine  at,  535 
strike  of  lode  at,  14 
Lead  lode  at  Wheal  Mary  Ann,  6 
ores,  dressing  of,  624 
modes  of  occurrence,  55 
state  of  in  gozzan,  101 
plant,  104 
poisoning,  687 

prevention  of,  687 
rivet  for  safety  lamps,  522 


INDEX. 


Lead-bearing    sandstone,    Mecher- 

nich,  1 8 

Lead,  mode  of  working,  320 
Leadville,  Colorado,  mode  of  occur- 
rence of  lead  ores  at,  55,  57 
Lease  system  in  Colorado,  647 
Leather  packing  for  pumps,  448 
Leats,  293 
Leavitt  stamp,  553 
Legal  definition  of  the  term  lode,  8 
Legislation     affecting    mines    and 

quarries,  653 
Leg,  or  side-prop,  232 
Legrand's  steel  sleeper,  352 
Lenneschiefer,  Liiderich  mine,  85 
Lesley  on  the  composition  of  natural 

gas,  59 

Lester's  stone-breaker,  547 
Levant  Mine,  changing  house  at,  679 
Level,  natural  ventilation  of  end  of, 

485 
use  of  air-sollar  in  ventilating 

end,  487 
Levels,  driving,  222 

iron  and  steel  supports  for,  255- 

263 

lined  with  masonry,  250 
methods  of  timbering,  232 
ventilating  lower,  489 
Liability  Act,  Employers',  666 
Lid,  244 

Lievin  Company,  shaft  sunk  by,  277 
Lifts  (Cleveland),  316 
Lighting  workings,  513 
Lime  cartridge,  208 
Limestone,     bituminous,     Val     de 

Travers,  22 
burning  of,  611,  613 
Lime-water  test  for  the  air  of  mines, 

502,  503 

Lindemann's  apparatus,  506 
Lining  boards,  445 
bore-holes,  131 
tube,  boring  by  revolving  the, 

117 

tube  for  brine  well,  305 
Linkenbach,  stationary  table  of,  581 
Liquefaction  of  carbonic  acid,  600 

use  of,  in  dressing,  597 
Listings,  237 
Lithofracteur,  214 
Liveing's  indicator  for    fire-damp, 

500 
Llanbradach     Colliery,     automatic 

water-tank  at,  437 
sinking  arrangements  at,  408 
steel  trams  at,  359 
Loading  kibble,  405 

skip  in  shaft,  410,  412 


Learning  (Australia),  106 
Lochs,  definition  of,  6 
Locked  coil  wire  rope,  382,  400 

socket  for,  403 

Lockhart's  gem  separator,  577 
Locks  for  safety  lamps,  522 
Locomotives  for  underground  use, 

363 

for  use  at  the  surface,  378 
Lode  at  Wheal  Mary  Ann,  6 
definitions  of,  5,  6 
legal  definition  of,  9 
modes  of  working,  325,  340 
narrow,  mode  of  working,  330 
wide,  with  weak  sides,  mode  of 

working,  331 
worked  away  in  slices  parallel 

to  dip,  335 
Lode-lights,  107 

Lodes,  conditions  affecting  produc- 
tiveness of,  1 1 
length  of,  along  strike,  1 1 
formed  by  alteration  of  the  en- 
closing rock,  7 
wide,  worked  with  pillars  and 

chambers,  338 
Lofting,  256 
Longwall  workings  for  copper-shale 

at  Mansfeld,  322 

Loose  ground,  supporting  excava- 
tions in,  242 
timbering  levels  in,  236 
Lorraine,  iron  ores  of,  53 
Loss  in  dressing  at  Churprinz  works, 

631 

at  Ems,  631 

at  Himmelfahrt  works,  630 
at  Pestarena,  631 
cause  of,  630 
slate,  631 
Lovett-Finney  magnetic  separator, 

603 

Lowmoor  jacket,  713 
Lubrication  of  mine  waggons,  358 
Luderich  zinc  mine,  85 
Lunge's  apparatus  for  testing  the 
air  of  mines,  503,  505 


M 


MACGEOKGE  on  deviation  of  bore- 
holes, 148 
Machine  drills,  181 

sieves,  566 
Machinery,  accidents  from,  711 

clothing  for  men  engaged  near, 

673 
Magnesium  ribbon  lamp,  517 


732 


INDEX. 


Magnetic  lock  for  safety  lamps,  522 
separation,  600 

bismuth  ore  with  magnet- 
ite, 606 

Namaqua  Copper  Co.,  606 
objects  of,  600 
Queensland,  606 
separators,  600 

Ball-Norton,  603,  606 
Buchanan,  604 
Chase,  60 1 
Conkling,  601 
Edison,  deflection,  606 

second,  602 
Hoffman,  602 
Kessler,  602 
King,  604,  606 
Lovett-Finney,  603 
Wenstrom,  605 
Magnetite,  dressing  of,  600 

jigging,  624 

Main  and  tail  rope  system  of  haul- 
age, 366 
Majendie,  Colonel,  on  the  effect  of 

oil  on  safety  fuse,  217 
Malay  Peninsula,  tin-bearing  alluvia 

of,  85 
Mallard  and  Le  Chatelier  on  testing 

for  fire-damp,  500 
Mallet,  or  sledge,  154,  159 
Man-engine,  534 

accidents  on,  705 
Manganese  ore,  dressing  of,  625 

occurrence  of,  57 
Mansfeld  copper-mines,  29 
adit  at,  434 

barracks  for  workmen,  674 
compound      pumping     engine, 

Ernst  IV.  shaft,  443 
compound      pumping     engine, 

Otto  IV.  shaft,  444 
cross-cut  lined  with   concrete, 

251 

descent  and  ascent  of  men,  532 

employes  living  in  own  houses, 
679 

hydraulic  counterpoise  to  pump 
rods,  458 

lamp  used  at,  516 

man-engine  at,  536 

method  of  working  copper- 
shale,  322,  325 

miner's  hat,  672 

pick  used  at,  153 

Kittinger  pump  at,  456 

thickness  of  bed  of  copper- 
shale,  5 

treatment  of  copper  ore  at, 
621 


Mansfeld  copper-mines — continued. 

underground  air  reservoirs  at, 
169 

underground  pumping  engines 

at,  467 
Marble,  58 

Maros-Ujvar,  arc-lamp  at,  524 
Marsaut  lamp,  521 
Marsden's  pulveriser,  547 

stone-breaker,  547 
Marshall,    discovery     of     gold     in 

California  by,  94 
Marsh-gas,  found  in  mines,  476 
Marston  Hall  mine,  311 
Marvin  drill,  198 
Masonry,  for  lining  levels,  249 

shafts,  252 

dam  in  shafts,  433 
Masses,  or  non-tabular  deposits  of 
minerals,  18 

methods  of  working,  340 
Matai  wood,  229 
Mather  and  Platt's  system  of  boring, 

142 

Mathet,  joint  for  air-mains,  170 
Matrix,  definition  or',  1 1 
Maul,  141 
Measure,  payment  by,  638,  639,  640 

and  time,  payment  by,  641 
Measuring  the  quantity  and  press- 
ure of  air  in  mines,  506,  512 

staff,  231 
Meat  earth,  286 
Mechanical  picks.  199 

processes  of  dressing,  538 

ventilation,  491 
Mechernich,  arc-lamp  at,  524 

barracks  for  miners,  674 

dressing  lead  ore  at,  625 

friability  of  ore,  607 

jumper  used  at,  157 

lead-bearing    sandstone    of,   5, 

method  of  working  lead-bearing 

sandstone,  320 
opencast,  289 
pumping  engines  at,  467 
siphon  separator  used  at,  579 
Medical  attendance,  deduction  for, 

639 

Medium  fan,  498 
Mercurial  poisoning,  symptoms  of, 

688 
vapour    in    quicksilver    mines, 

480 

Metales    frios,  or    unchanged    sul- 
phides, 1 01 

Metallic  supports  for  excavations, 
255 


INDEX. 


733 


Metalliferous  Mines  Regulation  Acts, 

656 

accident  statistics,  700,  701 
Mica,  dressing  of,  625 

mode  of  occurrence  of,  58 
Middlesbrough,   extraction   of  salt 

by  bore-holes,  305 
marsh-gas  with  brine,  476 
Mill,  Chilian,  557 
Huntington,  561 
Sturtevant,  563 
Close  lead    mine,    Derbyshire, 

explosion  of  fire-damp,  476 
Mills  for  grinding,  556 

or  passes,  330 
Mine,  atmosphere  of,  475 
definition  of,  i 
derivation  of  word,  i 
Miner,  clothing  of,  669 
condition  of,  669 
regulations  for  benefit  of,  655 
Minera  zinc  mine,  Wrexham,  86 
Mineral  deposits,  classification  of,  3 
repositories,  anomalies  in,  17 
veins,  connection  of,  with  faults, 

89 

formation  of,  14 
Minerals,  ownership  of,  653 
Minero  bird  at  Caratal,  105 
Miners'  cottages,  677 
housing,  673 
inch,  definition  of,  301 
Minette,  53 

Minieres,  definition  of,  i 
Mining,  comparative  healthiness  of, 

683 

definition  of,  i 

labour,   principles   of    employ- 
ment of,  637 
law,  in  France,  i 
in  Italy,  i,  2 

in  the  United  Kingdom,  i 
in  the  United  States,  8,  9 
statutes,  656 

relating  to  Derbyshire,  655 
to  Forest  of  Dean,  655 
subdivision  of  the  subject,  2 
Miscellaneous  pulverisers,  563 
Mispickel,  treatment   of,   611,   612, 

613,  619 
Miss-fire,  217 

danger  from,  213 
Moil,  231 
Molinello,  618 
Mona  and  Parys  mines,  cobbing  at, 

545 
Monier  system   of  using  concrete, 

254 
Monitor,  296 


Montana,  copper  deposits  of,  37 
Monte  Catini,  flora  of,  104 
Monteponi,  Sardinia,  adit  at,  435 

roasting  calamine  at,  615 
Moore,  pumps  worked  underground 

by  hydraulic  power,  469 
Moravia,   dressing  of  graphite   in, 

623 
Mortality,  comparative  figures,  683, 

684 

Moss-box,  273 
Mother    Lode    or    "  Great    Quartz 

Vein,"  California,  45 
Motion  of  particles  in  water,  568 
Mount  Bischoff,  dressing  tin  ore  at, 

630 

Morgan  gold  mine,  48,  97 
Mountfield  gypsum   mine,   Sussex, 

437 

Mueseler's  lamp,  520 

Mulberry  mine,  near  Bodmin,  19 
mode  of  working,  290 

Murgue,  on   the  resistance  to  air- 
current  due  to  sides  of  airway, 


NAMAQUA  COPPEE  Co.,   magnetic 

separator  used  by,  606 
Names      of     places,      information 

afforded  by,  no 
Natural  gas,   conveyance  by  pipes, 

373 

occurrence  of,  59 
Natural  ventilation,  482 
Needle,  161 

Neu-Stassfurt    mine,   electric  rail- 
way, 371 
Nevada,  Comstock  lode,  76 

mineral   deposits  at  Steamboat 

Springs,  75 
New  Almaden,  California,  73 

Brunswick,  antimony  ore  in,  21 
Caledonia,  cobalt  ore  in,  28 

nickel  ore  in,  60 
Idria,  working  by  reflected  day- 
light at,  513 
South  Wales,  alunite  in,  20 

tin-bearing  alluvia  of,  85 
Zealand,  trees  used  for  mining 

purposes,  229 
Nickel  ore,    discovery  of,  in  New 

Caledonia,  99 

ores,  mode  of  occurrence  of,  60 
Nitrate  of  soda,  mode  of  occurrence 

of,  62 

mode  of  working,  286 
preparation  of,  608 


or  THE 


734 


INDEX. 


Nitrate  mixtures  (explosives),  210 
Nitro-cellulose,  215 
Nitrogen  in  mines,  479 
Nitro-glycerine,  211 

products  of  explosion  of,  212 
Noble  and  Abel,  on  fired  gunpowder, 

209 
Noetling,  on  the   oil-fields  of  Bur- 

mah,  66 
Nog,  232 

Nolten,  on  finding  deviation  of  bore- 
holes, 148 

Northampton,  deep  boring  at,  118 
Northamptonshire,  mode  of  working 

iron  ore,  286 

North  Lancashire,   dressing  haema- 
tite in,  624 

working  hsematite  deposits,  343 
royalties  in,  654 
North  Wales,  iron  pyrites,  83 
slate  mines,  312 
washing  pit  used  in,  539 
North wich,  salt  beds  of,  75 
Nunnery  Colliery,  steel  beams,  256 
Nystagmus,  688,  689 


0 


OAK  for  timbering  excavations,  227 
Ochre  at  Parys  mine,  616 

dressing  of,  626 

Ochsenius,   on    the    origin    of   the 
nitrate  deposits  of  South  America, 

63 

Oeynhausen's  sliding  joint,  128 
Ogle,  Dr.,  on  annual  death-rates  in 

various  trades,  683,  684 
Ohio,  mode  of  occurrence  of  natural 

gas  in,  59 

Oil,  effect  of  on  safety  fuse,  217 
fields  of  Baku,  65 
of  Burmah,  65 
of  the  United  States,  67 
Oil-wells,  gases  met  with  in  sinking, 

477 

Oils  used  in  lamps,  515,  516,  519 
Olaf  Terp,  use  of  emery  for  boring, 

124 

Open-fire  drying,  592 
Open  works,  285 
Optimus  drill,  189 
Ormerod's  detaching  link,  416 
Osceola  Co.'s  mine,  arc-lamp  at,  525 
Otago,  New  Zealand,  lodes  of,  8 
Otto's    system    of    aerial  ropeway, 

382 

Outcrop  of  lodes,  98 
Overburden,  286 


Overhand  stoping,  329 

advantages  of,  331 
Overlap  fault,  90 
Overwinding,  422 
Ovuli,  51 

Ownership  of  minerals,  653 
Oxygen,  absorption  of,  480 

determination   of,   in  the    air, 
506 

necessity  for  a  large  proportion 

of,  505 
Ozokerite,  dressing  of.  626 

extraction  of,  by  benzine,  609 

mines,    Boryslaw,    inflammable 
gases  at,  477 

mode  of  occurrence  of,  63 

purification  of,  598 


PACKING  plunger  pump,  452 

pump  bucket,  448 
Pacos  (S.  America),  100 
Pan,  for  amalgamating  gold  ores, 
622 

for  grinding  and  amalgamating, 
556 

for  prospecting,  538 
Paragenesis  of  minerals,  97 
Parian  cement,  613 

preparation  of,  624 
Parodi  on  the  Sicilian  sulphur  beds, 

83 
Parys  mine,  extraction  of  copper  by 

solution,  307 
precipitation  at,  616 
Pass,  332 

best  form  of,  348,  349 
Patterson's  stamps,  551 
Paxman's     roller     for    Huntington 

mill,  561 
Pay-bill  for  payment  by  measure, 

638 

value  of  product,  642 
weight,  640 
Pay-lead,  318 

Payment  by  measure,  638,  639.  640 
time,  637 

time  and  measure,  641 
value  of  product,  641 
weight,  639 

Pearce,   on  the  tin-lodes    of   Corn- 
wall, 7 
Peeker,  222 

Penhall's  mine,    Cornwall,    succes- 
sion of  faults  at,  92 
Penrhyn  slate  quarry,  288 
Pensions,  693 


INDEX. 


735 


Percolation  of  surface  water  into 

workings,  429 
Percussion  tables,  584,  589 
Perpendicular     shafts,    advantages 

of,  325 

Pestarena,  loss  of  gold  at,  631 
Petroleum,  65,  66 

conveyance  by  pipes,  374 
extraction  by  wells,  304 
Petroleum  engine,  163 
for  pumping,  445 
for  working  drill,  180 
Pettenkof  er,  on  the  limit  of  carbonic 

acid  in  air,  502 

Phenolphtbalein,  use    of,   in    lime- 
water  test,  502 
Phillips,    on     the    mica    of   North 

Carolina,  58 

Phosphate  kiln,  American,  594 
Phosphate  of  lime,  67,  69 

discovery  of,  at  Beauval,  France, 

94 
in  South  Carolina  and  Florida, 

68,  69 

search  for,  by  piercing,  107 
treatment  of,  626 
weathering  of,  611 
Photometric  tests  of  light  given  by 

safety  lamps,  519,  520 
Physical   properties,   dressing  pro- 
cesses depending  on,  568 
Pick  and  gad  work,  154 

handles,  153 
Picking  by  hand,  541 
Picks,  152 

mechanical,  199 
sharpening,  153 
with  separate  blades,  153 
Picric  acid,   explosives  containing, 

215 
Pieler  lamp,  499 

testing    for    fire  -  damp     with 

hydrogen  flame,  500 
Piercing,  106 
Pigsty  timbering,  245 
for  levels,  234 
for  shafts,  239 
Pilar,  on  Franke's  mechanical  chisel, 

199 
Pillaring  of  slate,  81 

plane,  314 
Pillars  and  chambers,  working  wide 

lodes  with,  338 

left  as  permanent  supports,  309 
worked  away,  315 
Pine,    varieties    used    for    mining 

purposes,  227,  228 
Pipe- lines,  374 
Pipes,  conveyance  of  minerals  by,  349 


Pipes — continued. 

for  compressed  air,  170 

for  conveying  water,  295 

for  pump  column,  450 

wooden,  450 
Pitch  lake  of  Trinidad,  22 

of  a  shoot  of  ore,  definition  of, 
ii 

purification  of,  598 

pine,  227 

Pit-head  frame,  394 
Plane  tables,  579 
Planing  machines,  565 
Plank  tubbing  for  shafts,  266 
Plants,     indications     of     minerals 

afforded  by,  103 
Plaster  of  Paris,  613 

preparation  of,  624 
Plat,  405 

Plug  and  feathers,  208 
Plumbism,  687 
Plunger  pump,  451 
Plutonic  rocks,  3 
Pneumatic  hoisting,  427 

jig,  589 

Poetsch's  freezing  process,  281 
Pohle  pump,  470 
Points  and  crossings,  underground, 

354 

Poling,  236 
Pollution    Prevention  Act,   Eivers, 

667 
Pontgibaud    lead    mines,   carbonic 

acid  at,  475 
Poppet  heads,  394 
Post,  237 
Potassium  salts,  deposits  at  Stass- 

furt,  70 
discovery     of,    at      Stassfurt, 

96 

method  of  mining,  315 
treatment  of,  627 
Potosi,  78 
Precipitation,  616 
Premiums  for  good  conduct,  652 
Preparation  of  ores.— See  DRESSING, 

Preservation  of  timber,  229 
Pressure  of  air,  influence  on  health, 
689 

box,  295 
Pricker,  161 
Piibram,  deep  shafts  at,  404 

underground  fire  at,  708 
Priestman's  grab  dredger,  176 
Principles  of  employment  of  mining 

labour,  637 
Prop,  244 
Props,  iron  and  steel,  265 


736 


INDEX. 


Prospecting,  or  search  for  minerals, 

93 

by  the  diamond  drill,  119,  123 
by  the  diamond  drill,  cost  of, 

122 

Prospector,  qualifications  of,  112 
Provident  societies,  690 
Prussia,  accidents  from  man-engines, 

705 

Puddling  machine,  Australia,  539 
Pulley-frame,  394 
Pulleys,  397 
Pulsator,  622 
Pulsometer,  468 
Pulveriser,  Cyclone,  563 

Marsden's,  547 
Pulverisers,  miscellaneous,  563 

pneumatic,  563 
Pump  column,  450 

for  extracting  brine  from  bore- 
hole, 306 

lifting,  448 

plunger,  451 

plunger,  advantages  of,  452 

Pohle,  470 

pulsometer,  468 

Biedler,  467 

Rittinger,  454 

rods,  445 

counterbalancing,  457 
iron,  461 

valves,  453 
Pumping  engines,  compound,  443- 

445 

duty  of,  472 

placed  underground,  466 

single  acting,  443 

machinery,  moving  heavy  parts 
of,  461 

plant,  Shakemantle  mine,  461 
Pumps,  drainage  by,  441 

driven  compressed  air  or  elec- 
tricity, 470 

drowning  of,  450,  446,  467 

wooden,  450 

worked    by    hydraulic    power, 

469 
Purifying     water     from     dressing 

works,  667 
Pyrites,  Carnarvonshire,  83 

mode    of    working    in     North 
Wales,  309 

worked    opencast,    Rio    Tinto, 
289 


Q 


QUAEEIES,  definition  of,  I 

raising  stone  from  open,  406 


Quarries — continued. 

slate,  North  Wales,  312 
underground    sJate,    Ardennes, 

3H 

stone,  Bath,  310 
Quarry  Fencing  Act,  667 
Quartering,  sampling  by,  633 
Quenast  quarries,  premiums  for  good 

conduct,  652 
Quicksand,  Haase  process  of  sinking 

in,  283 
Poetsch  process  of  sinking  in, 

283 
Triger's  process  of  sinking  in, 

277 
Quicksilver,  chance  discovery  of,  in 

California,  94 
mines  of  California  and  Nevada, 

Becker  on,  16 

mines,  unhealthiness  of,  687 
ore,  occurrence  of,  71 
ore,  treatment  of,  627 
rock,  74,  103 


II 


RACK-A-EOCK,  211 
Ragging,  544 
Rails,  351 

Railways,  electric,  371 
surface,  376 
underground,  351 
Rammelsberg  Mine,  Hartz,  pyrites 

deposit,  32 

Rand,  gold  output,  43 
Ratchet  drill,  155 
Rating  Act,  655 

Raymond,  on  indicative  plants,  104 
Recreation,  696 

Red  clay  of  New  Caledonia,  28,  60 
Red  bar  (Johannesburg),  103 
Redonda,  phosphate  of  alumina  at, 

69 

Red  River,  tin  ore  got  from,  630 
Reflected    daylight,     working    by, 

5J3 

Regulations  for  mines,  working,  655 
Regulations. — See  ACTS,  656 
Reservoirs  for  compressed  air,  168 
for  hydraulic  mining  purposes, 

293 

Resistance  to  air-current,  510-512 
Restronguet  creek,  dressing  of  tin 

ore  at,  629 
method  of  working  tin-bearing 

gravel,  316 
occurrence  of  tin- ore  in  alluvium 

of,  85 
shaft- sinking  at,  268 


INDEX. 


737 


Reticulated  masses,  19 
Retorting  amalgam,  600 

sulphur  ores,  600 
Returning  charges,  642 
Reumaux's  automatic  speed  checker, 

425 

Revolving  round  table,  583 
Reversed  fault,  90 
Rewarewa,  229 

Rhosesmor  mine,  Flintshire,  435 
Rice's  clutch,  369 

Richness  of  lodes,  conditions  affect- 
ing, ii 

Richmond  v.  Eureka  case,  8 
Rickard,  on  Mount   Morgan  mine, 

Queensland,  49 
on  the  saddle-reefs  of  the  Ben- 

digo  gold-field,  47 
Riebeck's  stove,  595 
Riedler  pumps,  467 
Riffles,  299 
Rigg    and    Meiklejohn's    machine, 

203 

Rinchiusu,  475 
Rio  Tinto,  arc-lamp  at,  525 
character  of  ore  at,  33 
geology  of  the  district,  31 
gozzan,  33 
lodes  at,  32 
mines,   shipping  arrangements 

at  Huelva,  380 
opencast,  289 
pillar  and   chamber  workings, 

338 

precipitation  at,  616 
timbering  for  levels,  233 
treatment    of    copper    ore   at, 

621 
Rise,  difficulty  of  ventilating,  486 

mode  of  ventilating,  488 
Rises,  method  of  timbering,  344 
Rittinger,  fall  of  spheres  in  water, 

568 

Rittinger  pump,  445,  454 
Rittinger's  percussion  table,  584 
Rivers    Pollution    Prevention    Act, 

667 
Rivers,  sinking  shafts  in,  by  freezing, 

280 

Roasting,  611,  613 
Roberts,  C.  Warren,  sleeper,  353 
Roburite,  215 

fumes  from  explosion  of,  481 
Rock-boring  competition,  159 
Rock-drills,  177 
Rock-salt  at  Stassfurt,  70 
Rods  for  man-engines,  535 

for  pumps,  445 
Rolland's  tireless  locomotive,  363 


Rolls,  Cornish,  553,  554 

Krom,  554 
Roof  of  a  bed,  definition  of,  5 

slate  mining,  312,  313 
Root's  blower,  494 
Rope  haulage,  365 

preventing  shock  to,  in  winding, 

427 

socket,  139,  140 
Ropes  for  winding,  steel,  399 
modes  of  capping,  402 
testing,  427 

Rossigneux  system  of  counterbalanc- 
ing, 459 
Rotary  machine  drills,  178 

washing  machine  for  diamonds, 

540 
Rothliegendes  in  Mansfeld  district, 

29 

Rothschonberger  Stalin,  434 
Rou mania,  salt  mines,  312 
Roumanian  miner's  hat,  672 
Round  tables  for  picking,  542 

for  sluices,  581 
Rowoldt's  stove,  597 
Royalties,  654 

sliding  scale  for,  654 
Ruelle's  stove,  596 
Ruins,  indications  afforded  by,  109 
Running  loop,  447, 
Russia,  manganese  ores  of,  57 

occurrence  of    quicksilver  in, 

73 
Ry land's  glass-lined  pipe,  171 


S 


SABOT,  673 

Saddle  reefs,  Victoria,  47 

Safety  catches,  426 

on  cage,  418 
fuse,  217 
gear  for  hauling  men  at  Bory- 

slaw,  531 

lamp,  used  for  testing  for  fire- 
damp, 499 
lamps,  518 

St.  Agnes,  Cornwall,  tin  lodes  of,  84 
St.  Day  mines,  heat  at,  670 
Saint-Etienne,    mine-waggon    used 

at,  358 

St.  Just,  strike  of  lodes  at,  14 
Salisbury  Mine,  Johannesburg,  42 
Salt,    discovery    of    in    Cleveland 

district,  96 

excavating  by  water,  226 
extraction  by  wells  and  bore- 
holes, 304 

3  A 


INDEX.' 


Salt — continued. 

minerals  associated  with,  97 
mines,  Cheshire,  311 
Roumania,  312 
occurrence  of,  75 
preparation  of,  628 
workings  for  at  Bex,  307 
works  affected  by  Alkali  Acts, 

665 
Salzkammergut,   mode  of  working 

salt-marl,  307 
Sampling  by  hand,  632 
quartering,  633 
taking  out  small  lots,  632 
trenching,  632 
object  of,  632 
machine,  Bridgman's,  635 
Brunton's,  635 
Clarkson's,  634 
Colorado,  used  in,  634 
shovel,  633 
Sandals,  673 
San  Domingos,  34 
Sand-pump,  140 
Sand-reel,  139 
Sandstone,   bituminous,  California, 

22 

interstitial  space  in,  18 
lead-bearing,  Mechernich,  5,  18 
silver-bearing  of  Utah,  18 
Sarrau  and  Vieille,  on  the  decompo- 
sition of  certain  explosives,  212 
Savage  mine,  heat  at,  670 
Sawing  machines  for  stone,  564 
Saws,  circular,  use  for  undercutting, 

202 

for  cutting  stone,  154 
timbermen's,  231 
used  in  getting  freestone,  310 
wire,  204 

Sawyer  on  underset  of  props  in  in- 
clined beds,  244 
Saxon  gad,  154 

miner's  lamp,  516 
Schaffer    and    Budenberg's    speed 

indicator,  533 
Schiele  fan,  497 
Schools,  682 
Schrader  on  Franke's   mechanical 

chisel,  199 
Schulz's  stove,  597 
Scotch  fir,  228 
lamp,  516 

Scotchman's    United    mine,    bore- 
hole at,  148 
Scraper,  160 
Screening,  566 
Screw-conveyors,  375 
Seams,  18 
Seasoning  of  timber,  230 


Sector  wire  rope,  401 

Securite,  215 

Sediment-tube    for    diamond  drill, 

119 
Self -discharging  skips,  412 

advantages  of,  417 
Self -oiling  pedestals,  361 
Selvage,  definition  of,  1 1 
Separator,  Frongoch,  576 

Jacomety  and  Lenicque's,  575 
Lockhart's  gem,  577 
siphon,  577,  579 

Separators,  upward  current,  574 
Sergeant  drill,  193 

groove-cutter,  199 
Serpentine,  occurrence  of  asbestos 

in,  21 

occurrence  of  nickel  in,  61 
Sets  or  frames,  234,  236 
Seyssel,  France,   bituminous  lime- 
stone of,  22 
treatment  of  asphalt  rock  of. 

598 
Shaft  accidents,  705 

arrangement  of  pumps  in,  451, 

461,  464,  465 
linings  of  iron,  263 
natural  ventilation  of,  486 
rolls,  446 
use  of  air-pipe  for  ventilating, 

488 
Shafts,  cost  of  sinking  in  watery 

strata,  271 
crooked,  arrangement  of  pump 

rods  in,  446 
deep,  at  Pfibram,  404 
freezing    process    of    sinking, 

278 

for  working  mineral  deposits,3o8 
for  working  veins,  325 
Kind-Chaudron      process       of 

sinking,  271 

lined  with  concrete,  253 
lined  with  masonry,  252 
natural  ventilation  by  two, 

483 
Poetsch's  freezing  process  for 

sinking,  281 
sunk  by  boring  process,  time 

required,  277 
timbering  of,  236 
Shaft-sinking,  225 

by  incandescent  lamps,  524 
through  bed  of  river,  268 
Shakemantle  Mine,  pumping  plant 

at,  461 
Shanks'  system  of  treating  caliche, 

608 

Shaw's    apparatus    for  testing  for 
fire-damp,  501 


INDEX. 


739 


Sheba  Mine,  Barber  ton,  44 

Gold  Mine,  aerial  ropeway  at, 

384 

Shell  pump,  128 
Shipping    ores,   arrangements    for, 

380 

Sheading,  105 
Shoad-stones,  106 
Shoe  of  stamps,  549 

wooden,  673 

Shoot  of  ore,  definition  of,  1 1 
Shoots,  348,  373 

mouth     for     regulating      dis- 
charge of,  413 
Shovel,  151 
Shower-bath    for    miners,     Anzin, 

68 1 
Siberia,  freezing  method  of  sinking 

pits,  278 

Sicilian  miner's  lamp,  515 
Sicilian  mines,  steps  for  descent  or 

ascent,  527 

Sicily,  modes  of  working  sulphur- 
bearing  limestone,  321 

occurrence  of  sulphur  in,  82 
Sickness,  683 
Side  holes,  310 

Sidings,  endless  rope  system,  370 
Sieves,  566 
Signalling,  420 

from  cage,  533 
Sill,  233 

Silver,  chance  discoveries  of,  95 
Silver  ores,  occurrence  of,  76 

Broken  Hill,  N.S.W.,  78 

Calico,  California,  79 

Comstock  Lode,  Nevada,  76 

Eureka  Richmond,  Nevada,  76 

Huanchaca,  Bolivia,  78 

Kongsberg,  Norway,  12 

Stormont,  Utah,  79 

treatment  of,  628 
Silver-bearing  sandstone,  Utah,  18 
Simultaneous  fuse,  220 
Single-rope  haulage,  365 
Sink,  222 
Sinker-bar,  139 

Sinking  by  compressed  air  method, 
influence  on  health,  689 

Kind-Chaudron  method,  271 

Poetsch,   or   freezing    method, 
281 

shafts,  225 

through  watery  strata,  cost  of, 
271 

Triger's  method,  277 
Siphon,  draining  mines  by,  437 
Siphon  separator,  577 
Skertchly  on  the  mining  and  knap- 
ping of  flint,  41 


Skip,  404,  410 

loading  in  shaft,  410,  412 

self -discharging,  De  Beers  in- 
clined shaft,  412 

for  perpendicular  shaft,  415 
Skutterud,  cobalt  ore,  27 
Slag-heaps,  indications  afforded  by, 

1 08 
Slate,  charging  holes  forrending,  219 

circular  saws  used  for,  564 

dressing  machines,  565 

loss  in  dressing,  631 

loss  in  mining,  314 

methods  of  working,  312-315 

Mines  (Gunpowder)  Act,  659 

occurrence  of,  79 

planing  machines  for,  565 

preparation  of,  628 

splitting  of,  545 
Sledges,  350,  375 
Sleepers,  steel,  352 
Slickensides,  10,  89 
Slide,  88 

Slides  for  descent,  527 
Sliding  joint,  Oeynhausen's,  128 
Sliding  scale  for  royalties,  654 

Slip,  473 
Slopes,  308 
Sludger,  128 
Sluices,  297 

Smith,  Dr.  Augus,  on  the  candle- 
test,  501 
on  the  pollution  of  the  air  in 

mines,  480 
on  the  proportion  of  oxygen  in 

respirable  air,  506 
process  of  testing  air,  502 
Richard,   on  the    gold-bearing 
conglomerate  of  the  Trans- 
vaal, 42 

Snell,  on  miners'  nystagmus,  689 
Snore-piece,  448 

Snow,  disappearance  of,  from  out- 
crop of  lode,  1 08 
Societies,  provident,  690 
Sockets,  joining  two  ropes  by,  494 
Solepiece,  233 
Solfatara  of  Pozzuoli,  sulphur  from, 

82 
Solution,  extraction  of  minerals  by, 

305 

preparation  of  borax  by,  608 
nitrate  of  soda  by,  608 
potassium  chloride  by,  608 
Somme  department,  occurrence  of 
phosphate  of  lime  in,  68 
treatment  in,  627 
Somorrostro,  endless  chain  haulage, 

379 
self-acting  incline,  376 


740 


INDEX. 


Sorby,  on  the  origin  of  the  Cleve- 
land ironstone,  18,  53 
Sores  produced  by  arsenious  acid, 

686 

Sough,  433 

Sounding,  testing  ground  by,  705 
Sources  of  mineral  supply  in  British 

Isles,  655 
South  Africa,  discovery  of  diamonds 

in,  93 

dressing  of  diamonds,  621 
gold  ore  deposits,  41 
South  Carolina,  phosphate  beds,  68 
treatment  of  phosphate  of  lime 

in,  627 
South  Staffordshire  Mines  Drainage 

Commission,  474 
Space  required  per  head,  in  rooms, 

676 
Spain,  cupreous  pyrites  deposits  of, 

3J-34 

occurrence  of  quicksilver  in,  72 
Spalling,  544 

Spathose  ore,  calcination  of,  612 
Spear-rod,  445 
Speed  indicator  for  winding  engine, 

533 

Spider  (candle-holder),  515 
Spiles,  345 

Spilling,  or  spiling,  236,  242 
Spiral  drum,  393 
Splitting  air- current,  510 

slate,  545 

Sprague  electric  diamond  drill,  180 
Sprengel  type  of  explosives,  215 
Spring  stamps,  551 
Spruce  fir,  228 

Square-set  system  of  timbering,  246 
Squib,  218 
Stalls,  309 
Stamps,  gravitation,  548 

pneumatic,  551 

spring,  551 

steam-hammer,  551 
Standards  for  wire  ropeways,  382 
Stanley's  tunneller,  207 
Stannaries  Act,  668 
Stapff,    on    prospecting   for    phos- 
phorite, 104 

Stassfurt,    discovery  of  potassium 
salts  at,  96 

occurrence  of  potassium  salts 
at,  70 

preparation  of  salts  at,  608 

salt  mines,  sulphuretted  hydro- 
gen at,  479 

treatment  of  potassium  salts,627 

workings  for  carnallite,  315 
Stationary  engines  for  haulage,  364 

table  of  Linkenbach,  581 


Statutes  affecting  mines  or  quarries, 
656,  659,  662,  665 

Mining,  656 

See  ACTS  OP  PABLIAMBNT,  655 
Steamboat  springs,  Nevada,  75 
Steam  digger,  173 

engines  for  winding,  390 

hammer  stamps,  551 

jet  for  ventilating,  492 

process  for  sulphur,  600 

shovel,  173 

stove,  597 
Steavenson  twist    drill    driven    by 

power,  1 80 

Steel    beams  used  for  supporting 
levels,  256,  258 

car  wheels,  357 

frames  for  levels,  259 
shafts,  263 

mine-waggons,  356,  360 

props  for  working  places,  266 

pump  rods,  445 

sleepers,  352 

wire-ropes,  399 
Stein's  endless  belt,  586 
Stelzner,  on    the  lateral   secretion 

theory,  15 
Stempels,  240,  329 
Step-fault,  88 
Steps  for  descent  and  ascent,  526 

or  stopes  in  open  works,  width 

of,  286,  288,  289 
Stockworks,  19 

quicksilver  ore,  73 

silver  ore,  79 

tin  ore,  19,  84 

zinc  ore,  87 
Stokes'  alcohol-reservoir  for  safety 

lamp,  500 
Stone,  preparation  of,  628 

breakers,  546 
Stoping,  overhaud,  329 

underhand,  327 
Stoves,  for  drying,  594 

Jacobi's,  597 

Krom's,  595 

Eiebeck's,  595 

Rowoldt's,  597 

Ruelle's,  596 

Schulz's,  597 

steam,  597 

Strapping  plates,  445 
Stratified  deposits,  4 
Straw  for  firing  shots,  218 
Stream  works,  tin  ore,  85 
Strength  of  explosives,  216 
Stretcher-bar,  197 
Stretchers,  713 
Strike,  definition  of,  5 

influence  of  change  of,  on  veins,  1 3 


INDEX. 


741 


Stringy  bark,  229 
Struve's  ventilator,  494 
Studdles,  237,  243 
Stull,  327 

Sturgeon  on  the  efficiency  of  com- 
pressed air,  164 
Sturtevant  Mill,  563 
Styria,  graphite  in,  50 
Sublimation,  formation  of  veins  by, 

Sub-Wealden  boring  near  Battle,  96 
Suction  dredge,  177 

pipe  for  brine  well,  306 

pumps,  448 
Sudbury,  discovery  of  nickel  ore  at, 

94 

nickel  ores  of,  61 
Suffocation  by  gases,  707,  710 
Sulphate  of  iron  used  for  preserving 

timber,  231 

Sulphur,  distillation  of,  600 
liquation  of,  598 
mode  of  occurrence  of,  81 
preparation  of,  629 
rock,  Sicily,  fire-damp   emitted 

by,  478 
Bank  Mine,  California,  74 

discovery  of  quicksilver  at, 

96 

gas  from  hot  springs,  476 
bearing    limestone    in    Sicily, 

82 

mode  of  working,  321 
seams,  outcrop  of,  102 
Sulphuretted  hydrogen    in    mines, 

479 

Sulphurous  acid  in  mines,  479 
Sump,  326 

Supporting  excavations,  227 
Surface  accidents,  711 
drainage,  429 

indications  guiding   the   pros- 
pector, 97 

Surveying  bore-holes,  147 
Surveys,   danger   from  inaccurate, 

707 
Sussex,    preparation     of     gypsum, 

624 

Sussmann  electric  lamp,  523 
Sutro  Tunnel,  Nevada,  436 
Swab-stick,  160 
Swage,  181 
Sweden,  iron  ores  of,  54 

occurrence  of  zinc  ore  in,  87 
searching  for  iron  ore  with  the 

magnetic  needle,  112 
Switzerland,     workings     for     salt, 

307 

Sword,  448 
Synclinals,  47,  87 


TABLES,  Jacomety  and  Lenicque's, 
583 

Linkenbach's,  581 

percussion,  584,  589 

picking,  542 

plane,  579 

revolving  round,  583 

Kittinger's  percussion,  584 

round,  581 
Tabular  deposits,  5 
Tachometer,  533 
Taeglichsbeck's  report  on  housing 

of  miners,  674,  679 
Tagieff' s  spouting  oil-well,  Baku,  65 
Tailings,  243,  588 

Tamarack  copper  mine,  Lake  Supe- 
rior, 36,  37 
Tamping  bar,  160 

charge,  217 
Tapering  ropes,  404 
Taxation  of  mines,  625 
Tasmania,  dressing  tin  ore  in,  630 
Teague's  aspirator,  493 

noiseless  valve,  453 
Teel's  Marsh,  borax  deposit,  23 
Telephones   used  for  signalling  in 

mines,  421 
Temper  screw,  140 
Temporary  dam,  433 
Testing  air  of  mines,  498-510 

ropes,  427 

Thames  gold-field,  New  Zealand,  13 
Tharsis,  pyrites  mines,  34 
Thawing  dynamite,  213 
Thickness  of  bed,  measurement  of,  5 
Thrift,  690 
Throw,  or  heave,  88 
Throw  of  a  fault,  definition  of,  89 

mode   of  determining   amount 

of,  89 

Timber,  decaying,  affects  air  of  mine, 
480 

kinds  used  underground,  227 

preservation  of,  229 

seasoning,  230 

supports  compared  with  steel, 
257 

used  in  Australia,  228 
in  England,  227 
in  United  States,  228 

withdrawing,     from     rubbish, 

Foxdale,  338 
Timbering  in  loose  ground,  242 

levels,  232 

pigsty  system,  234,  239,  245 

shafts,  236 

special  excavations,  Hartz,  241 

square-set,  246 

working  places,  244 


742 


INDEX. 


Time    occupied    in     descent    and 
ascent  at  Mansfeld,  532 

payment  by,  637 

and  measure,  payment  by,  641 
Tin    ore,  alluvial    deposit    at  Re- 
st ronguet  Creek,  316 

calcination  of,  612,  613 

dressing  of,  629 

lodes  in  granite,  7 

mines  affected  by  Alkali  Acts, 
665 

mode  of  occurrence  of,  83 

separation  from  copper  ore,  609 

stockwork,  Mulberry  mine,  near 

Bodmin,  19 
Toadstone,  influence  on  lead  veins 

in  Derbyshire,  13 
Tonite,  215 

fumes  from  explosion  of,  481 
Tools  used  for  working  timber,  231 
Toothed  rolls,  556 
Torches,  515 
Torpedo,  304 

Transmission  of  power,  163 
Transport  above  ground,  373 

underground,  348 
Trays,  349 

Treadwell  Mine,  Alaska,  47 
Treatment  of  ores. — See  DRESSING, 

Trelease's  valve,  453 
Trenching,  sampling  by,  632 
Tribute,  641 

advantages  of  working  on,  643, 
646 

disadvantages  of  working  on, 
644,  645 

system  in  Colorado,  647 

at  Festiniog,  649,  651 
Triger's  method  of  sinking,  277 
Trimming  stone  by  hand,  546 
Trinidad,  Pitch  Lake  of,  22 

dressing  of,  619 

purification  of,  598 
Tripoli,  occurrence  of  beds  of,   in 

Sicily,  82 

Trommels,  566,  567 
Trouve",   apparatus  for    examining 

bore-holes,  150 
Trubi,  82 
Truck  Acts,  668 
Tubbing  for  shafts,  cast -iron,  268 

wood,  266 

Tunnelling  machines,  206 
Turbine,  used  for  hoisting.  389 
Turgu-Ocna  mine,  312 
Turn  plates,  354 
Tuscany,  occurrence  of  boric  acid,  25 

preparation  of  boric  acid,  620 
Tutwork,  638,  639 


r 


ULVERSTON,  haematite  deposits  of, 

19 

Umber,  dressing  of,  626 

searching  for  by  piercing,  106 
Undercurrents,  299 
Undercutting  machines,  199,  202 
Underground  pumping  engines,  466 

workings,  308 
Underhand  stoping,  327 
Underlie  or  underlay,  definition  of,  9 
United  Kingdom,  death-rate   from 

accidents,  700 

United  States,  candle-holder  used 
in,  514 

gathering  of  natural  ice,  5 1 

lamp  used  in,  516 

legal  definition  of  lode  in,  9 

occurrence  of  copper  in,  34 

gold  ore,  45 

iron  ore,  54 

lead  ore,  55 

natural  gas,  59 

petroleum,  67 

phosphate  of  lime,  68 

quicksilver  ore,  7  r 

silver  ore,  76 

trees  used  for  rnmine;  purposes. 

228 

Universal  pick,  153 
Unstratified  deposits,  4 
Upcast  shaft,  484 
Uppers,  dust  from  boring,  685 
Upthrow,  91 

Upward-current  separators,  574 
Utah,  silver-bearing  sandstone,  79 


VAL-DE-TRAVERS,  Switzerland,  bi- 
tuminous limestone  of,  22 
Value  of  product,  payment  by,  641 
Valve,  butterfly,  453' 

double-beat,  454 

Jan  Ham's,  453 

Hake's  mouth,  453 

ordinary  leather,  448 

Teague's  noiseless,  454 

Trelease's,  453 
Van  den  Broeck  and  Rutot,  portable 

boring  outfit,  117 
Van  lode,  length  of,  1 1 
Van  mine,  fire-damp  at,  476 

method   of  working    the  wide 

lode,  331 

Vanner,  Frue,  585 
V-bob,  446 
Vegetation  on  outcrop  of  lodes,  107 


INDEX. 


743 


Veins,  definition  of  term,  5 

heave  sideways  caused  by  slip 

along  line  of  dip,  91 
influence  of  change  of  strike  on, 

13 

of  enclosing  rock  on,  12,  13 
intersections  of,  12 
mechanical  filling  of,  14 
modes  of  working,  325-340 
name  applied  to  slate  beds  in 

North  Wales,  81 
origin  of,  14 
varying  width  of,  16 
Zimmermann's  rule  for  finding 

faulted  portion  of,  91 
Veinstone,  definition  of,  1 1 
Velocity  of    air-current,    measure- 
ment of,  506,  507 
Venezuela,  discovery  of  gold  in  by 

Plassard,  94 

occurrence  of  gold  in,  44 
Ventilating    appliances,    efficiency 

of,  509 
Ventilation,  475 

compressed  air,  492 
fans,  494 
furnace,  490 
steam  jet,  492 
water  blast,  492 

falling  down  shaft,  486 
effect  of,  on  timber,  230 
measurement  of  amount  of  air 

passing,  506 
natural,  482 

Victoria,  gold-fields  of,  46 
Villiers'  stopping  gear,  425 
Viola  calaminaria,  104 
Volcanic  emanations,sulphurfrom,8 1 

rocks,  3 

Vom  Kath   on  the  outcrop  of  the 

silver  veins  of  Butte,  Montana,  98 

Von  Cotta,  definition  of  a  mineral 

vein,  6 

on  the  Zwitter  of  Altenberg,  84 
Von     Groddeck,    definition     of    a 

mineral  vein,  6 
Von    Sandberger,    definition    of    a 

mineral  vein,  6 

on  the  lateral  secretion  theory,  15 
Vugs,  definition  of,  6 
Vulcano,  sulphur  from,  82 

W 

WADDLE  fan,  497 

Waggons  for  underground  use,  350, 

35S-36o 

points  to  be  considered  in  de- 
signing, 361 


Wales,  barracks  for  workmen,  676 

manganese  ore  in,  58 

lead  ore  in,  331 

slate  in,  79 

underground  workings  for  slate, 

312 
Walker's  circular  saw,  203,  204 

detaching  hook,  423 

shutter  for  Guibal  fan,  496 
Wallace  on  emanations  of  carbonic 

acid  at  Alston  Moor,  475 
Wallaroo  lode,  discovery  of,  93 
Walling,  249 

Walling  stage,  Galloway's,  409 
Wall-plate,  236 
Wall-posts,  240 
Walls,  Cleveland,  315 

Festiniog,  312 

of  a  lode,  definition  of,  10 
Walton  Brown  on  the  resistance  to 

air-currents,  511 

Wardwell    stone-channelling     ma- 
chine, 202 

Warming  pan  for  dynamite,  213 
Warocquere,  706 
Washer,  Australian,  539 

De  Beers,  540 

revolving  drum,  541 
Washing  ores,  &c.,  538 
Wash-out  fault,  87 
Washing-pit  used  in  North  Wales, 

539 

Water,    amount    used    by    siphon 

separator,  579 

amount  used  in  stamping,  551 
barrel  for  winding,  437 
column  compressors,  165 
excavating  by,  226,  292 
from  dressing  works,  purifica- 
tion of,  667 
gauge,  508 

irruptions  of,  into  mines,  707 
jet  ventilating  apparatus,  492 
motion  of  particles  in,  568 
power  used  for  working  pumps, 

442 

spray  for  laying  dust,  685 
tanks,  automatic,  438 
used  for  rending  rocks,  208 
wheel  used  for  hoisting,  389 

Watertight  linings  for  shafts,  266 

Weathering      of     diamond-bearing 

rock,  610 
fire-clay,  611 
ironstone,  611 
phosphate  of  lime,  61 1 

Wedge,  154,  208 

Elliott  multiple,  208 

Wedging-crib,  267,  270 

Weight,  payment  by,  639 


744 


INDEX. 


Wells,  304 

boring  by  rotation,  117 
driven,  137 
Wells  light,  516 
Welsh  barracks,  676 

manganese  ore,  occurrence  of, 

58 

dressing  of,  625 
lead  ore,  331 
miner's  clogs,  672 
slate  mines,  79,  312 
Wenstrom  magnetic  separator,  605 
Werner,    definition    of    a    mineral 

vein,  6 

Wery's  stopping  gear,  425 
West    and     Darlington,    hydraulic 

counterpoise,  458 
hydraulic  plungers  for  working 

inclined  rods,  447 
Wheal  Mary  Ann,   section  of  lode 

at,  6 

Wheelbarrow,  350 
Wheels  for  mine-waggons,  357 
Whipsiderry,  388 
White's  sleeper,  353 
Whitney,    on    the    "  Great   Quartz 

Vein  "  of  California,  45 
Wicks,  candle,  513 
Wide    veins,  method  of  working, 

331 
Wieliczka  salt  mines,  315 

timber  chocks,  245 
Wind-bore,  448 
Winding,  387 

drum,  391 

engines,  390 

men  at  Cam  Brea  mine,  533 

pulleys,  397 

removing  water  by,  437 
Windlass,  388 
Windmills  used  for  working  pumps, 

442 

Winstanley's  machine,  204 
Winze,  326 
Winzes,  use  of  for  ventilating,  489, 

490 
Wire  saw,  204 


Witwatersrand,  41 

Wolf's    magnetic    lock   for    safety 

lamps,  522 

Woodbury  ore  concentrator,  586 
Wooden  pipes,  450 

plugs   used  for  rending  rocks, 

208 

pulley  frame,  395 
Working  barrel  of  pump,  448 

in   constrained  position,  effect 

on  men,  688 

masses    by     horizontal    slices, 
ascending,  345 
descending,  341 
mineral  deposits,   methods   of, 

285 
places,  iron  and  steel  supports. 

265 

supported  by  masonry,  254 
timbering,  244 
regulations  for  mines,  655 
Workings,  carbonic  acid  in  old,  501 

laying  out  open,  288 
Workmen,  housing,  673 
Wotherton  mine,  Shropshire,  13 
Wrist,  310 
Wrysgan  mine,  314 


YELLOW  Jacket  mine,  heat  at,  670 


ZIMMEKMAN'S  rule  fo'r  finding  lost 

part  of  a  vein,  91 
Zinc    blende,    minerals  associated 

with,  97 
Diepenlinchen,       method       of 

working,  346 

ores,  calcination  of,  612,  615 
dressing  of,  625,  630 
occurrence  of,  85,  86 
Z  witter,  or  tin-bearing  rock  at  Alten- 
berg,  84 


Printed  by  BALLANTYNE,  HANSON  <S~  Co. 
London  and  Edinburgh. 


RETURN 


LOAN  PERIOD  1 

2 

3 

4 

5 

6 

ALL  BOOKS  MAY  BE  RECALLED  AFTER  7  DAYS 


DUE  AS  STAMPED  BELOW 

DMENRIF 

PER  24  1985 

RECCIRFEB  26  19J 

5 

UNIVERSITY  OF  CALIFORNIA,  BERKELEY 
FORM  NO.  DDO,  5m,  12/80          BERKELEY,  CA  94720 


?  ?•  V  r 


m. 


*  V 


r 


-:• 


